Education & Training

  • Ph.D. 2019

    Physics

    Bangladesh University of Engineering and Technology

  • M. Phil. 2015

    Physics

    Bangladesh University of Engineering and Technology

  • M. S. 2010

    Physics

    University of Dhaka

  • B. Sc. (Hons.) 2009

    Physics

    University of Dhaka

  • Introductory Training Course in Nanofabrication Technologies 10 - 28 September, 2018

    Nanofabrication Technologies

    Centre for Nano Science and Engineering, IISc, Bengaluru, India

Honors, Awards and Grants

  • 2018
    Bangabandhu Science and Technology Fellowship 2017-2018 for Ph. D. program
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    Awarded by Bangabandhu Science and Technology Fellowship Trust. 

  • 2006
    Scholarship for securing First Class in B. Sc. (Hons.)
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    Awarded by University of Dhaka.

  • 2002
    Scholarship for securing First division with star mark in H. S. C.
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    General grade scholarship awarded by Board of Intermediate and Secondary Education, Rajshahi.

  • 2000
    Scholarship for securing First division with star mark in S. S. C.
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    General grade scholarship awarded by Board of Intermediate and Secondary Education, Rajshahi.

  • 1997
    Government Junior Scholarship
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    Talent pool scholarship, Santahar Harvey Girls High School, Thana: Adamdighi, District: Bogra, Division: Rajshahi

  • 1994
    Government Primary Scholarship
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    Talent pool scholarship, S.M. I Academy, Thana: Adamdighi, District: Bogra, Divsion: Rajshahi.

  • 10-12 March, 2016, Atomic Energy Center, Dhaka-1000, Bangladesh
    Best Poster Presentation Award for 2 Posters
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    International conference on Physics-2016 organized by Bangladesh Physical Society

  • 10 - 14 July, 202310 - 14 July, 2023
    8th ICWIP-2023 Accessibility Grant8th ICWIP-2023 Accessibility Grant
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    8th International Women in Physics Conference (ICWIP) 2023 organized by International Union of Pure and Applied Physics (IUPAP), 10 - 14 July, 2023.

  • 1 - 3 March, 2018, Dhaka, Bangladesh
    The best poster paper award
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    4th International Conference on STRUCTURE, PROCESSING AND PROPERTIES OF MATERIALS 2018

  • 09 - 11 March 2023
    Best Oral Presentation Award
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    Awarded as the best oral presentation in the "Thin Films" session of "National Conference on Physics-2023" organized by Bangladesh Physical Society

  • 08-09 December 2022, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh
    Best poster award
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    7th Conference of Bangladesh Crystallographic Association organized by Bangladesh Crystallographic Association

  • 07-09 February 2019; University of Dhaka, Dhaka-1000, Bangladesh
    Best Poster Award for 2 posters
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    National Conference on Physics – 2019 organized by Bangladesh Physical Society

  • 05-07 March, 2020 Atomic Energy Centre, Dhaka-1000, Bangladesh
    Best oral presentation award in Thin Film Session
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    International Conference on Physics - 2020 organized by Bangladesh Physical Society

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SUBSTRATE TEMPERATURE DEPENDENCE OF SURFACE MORPHOLOGY AND STRUCTURE OF N-TYPE Fe2O3 THIN FILMS WITH ENHANCED TRANSPARENCY

MEHNAZ SHARMIN, JIBAN PODDER AND KHANDKER SAADAT HOSSAIN

Abstract

This work reports the effect of substrate temperature (TS) on the structure, surface morphology, optical, and electrical properties of iron (III) oxide (Fe2O3) thin films. Fe2O3 thin films were deposited from the aqueous solution of ferric chloride hexahydrate at various TS between 573 and 773 K using the spray pyrolysis technique. In field emission scanning electron and atomic force microscopic analysis, the surface of Fe2O3 films comprised nanoparticle clusters. In X-ray diffraction analysis, Fe2O3 thin films showed a rhombohedral-hexagonal structure with the predominant orientation along (104) crystallographic plane. Crystallite size reduced from 28 to 13 nm with the increase of TS between 573 and 773 K. In UV-vis- NIR spectroscopy, the highest transmittance was found to be 76% for the film deposited at the TS of 673 K. Band gap of the film was obtained between 2.05 - 2.09 eV. The electrical resistivity of the films ranged from 2.2  105 to 9.0  105 Ω-cm. The films contained n-type majority carriers with carrier concentration in the order of 1018 cm-3. Fe2O3 thin films with wide band gap, high transparency, and n-type conductivity indicate that the films are suitable for Fe2O3 in optoelectronic applications.

Role of female physicists during the COVID-19 pandemic in Bangladesh and their career challenges and opportunities

S. K. Choudhury, K. H. Maria, M. A. Bhuiyan, Mehnaz Sharmin

Abstract

The status of Bangladeshi women in physics in terms of enrollment, academia, and research remains the same
as was previously reported [1]. Because of the COVID-19 pandemic, all academic institutions in the country have been
closed since March 2020. Online classes have been held; however, lab classes have not been possible. Other important
issues, such as financial support for students who had been supporting themselves through home tutoring, were addressed
by female physicists through the Annesha Science Society. Most funds come from donations, mainly from teachers,
scientists, and other philanthropists. Along with financial support, female physicists are regularly providing mental support
to undergraduate and postgraduate students to keep the students mentally strong during pandemic conditions. Female
physicists have been active in holding Zoom meetings featuring doctors and scientists, participating virtually from home
and abroad, discussing COVID-19 issues and remedies. In addition, female physicists participated as invited speakers at
home and abroad virtually in international events. Furthermore, they continued their research work by analyzing previously
acquired data, advancing new theoretical modelling and simulation, and organizing online meetings and discussions among
group members and collaborators, which has led to many publications in internationally reputable journals. The challenges
faced by female physicists in Bangladesh are mainly family commitments, lack of funds, and discrimination. Opportunities
for female physicists are less than those available to their male counterparts for various reasons, including social attitudes.
Data are presented for postgraduate students who were in physics and building their careers prior to the onset of the
pandemic.

Enhancement of the structural, morphological, optical, and electrical properties of Mn doped CuO thin films via spray pyrolysis

P. DATTA, M. SHARMIN, J. PODDER3, S. CHOUDHURY

Abstract

Manganese (Mn) doped copper (II) oxide (CuO) thin films with 0 to 6 at% Mn doping were prepared onto the glass substrates at a temperature of 523 K using spray pyrolysis technique. The CuO and Mn doped CuO films showed monoclinic structure with the preferential orientation along (1̅11) and (111) planes after being annealed at 723 K in air for 60 min. The film surface was observed to be comprised of agglomerated nanoparticles under Scanning Electron Microscopy. Elemental composition of the films was confirmed by Energy Dispersive X-ray analysis. Optical transmittance and band gap of CuO thin film increased with Mn doping up to 4 at% in the visible-infrared region of light. Electrical resistivity of the samples decreased from 2.69×103 to 1.62×103 Ω-m with the increase of Mn doping. Activation energy of the films varied from 0.08 to 0.29 eV in the temperature region 323 - 383 K, whereas it varied from 0.29 to 0.40 eV in the temperature region 383 - 423 K.

Band gap tuning and p to n-type transition in Mn-doped CuO nanostructured thin films

R. Rahaman , M. Sharmin and J. Podder

Abstract

Here we discuss the synthesis of copper (II) oxide (CuO) and manganese (Mn)-doped CuO thin films varying with 0 to 8 at% Mn using the spray pyrolysis technique. As-deposited film surfaces comprised of agglomerated spherical nanoparticles and a semi-spongy porous structure for 4 at% Mn doping. Energy dispersive analysis of X-rays confirmed the chemical composition of the films. X-ray diffraction spectra showed a polycrystalline monoclinic structure with the predominance of the ( 11) peak. Optical band gap energy for direct and indirect transitions was estimated in the ranges from 2.67–2.90 eV and 0.11–1.73 eV, respectively. Refractive index and static dielectric constants were computed from the optical spectra. Electrical resistivity of CuO and Mn-doped CuO (Mn:CuO) thin films was found in the range from 10.5 to 28.6 Ω·cm. The tiniest electron effective mass was calculated for 4 at% Mn:CuO thin films. P to n-type transition was observed for 4 at% Mn doping in CuO films. Carrier concentration and mobility were found in the orders of 1017 cm–3 and 10–1 cm2 /(V·s), respectively. The Hall coefficient was found to be between 9.9 and 29.8 cm3 /C. The above results suggest the suitability of Mn:CuO thin films in optoelectronic applications.

Influence of Ni doping on the morphological, structural, optical and electrical properties of CuO thin films deposited via a spray pyrolysis

Join Uddin, Mehnaz Sharmin, Mohammed Nasim Hasan, Jiban Podder

Abstract

Nanostructured copper oxide (CuO) and Nickel (Ni)-doped CuO thin films with different concentrations of Ni ranging from 2 to 8 at.% were synthesized onto a plain glass substrate at the substrate temperature, 350 ◦C by a thermal spray pyrolysis technique. Field emission scanning electron microscopy (FESEM) analysis of CuO and Nidoped CuO thin films detected the closely spaced rock-like nanostructures, evenly distributed on the film surfaces. The average particle sizes of CuO and Ni-doped CuO thin films were calculated from the FESEM and found between 260 and 63 nm. Energy-dispersive X-ray analysis revealed that CuO and Ni-doped CuO thin films were stoichiometric and typically comprised of Cu, O, and Ni. X-ray diffraction analysis showed the monoclinic
structure of the films with the most preferred orientation plane (111) along with the (111), (202) and (022) crystalline planes. The maximum crystallite size was found at about 81 nm for 6 at% Ni-doped CuO thin film. CuO film showed an optical transmittance of about 33% in the visible-NIR region. Ni-doping enhanced the absorbing nature of CuO thin films in the vis-NIR region of light. With the rise of Ni content in CuO thin films, the optical bandgap gradually increased from 2.28 to 2.78 eV. Resistivity raised from 9.28 × 103 to 49.01 × 103 Ω-cm with the increase of the amount of Ni.

Bandgap tuning in ZnO thin films and enhanced n-type properties through Mn doping synthesized by a simple spray pyrolysis

Md. Khorshed Alam, Mehnaz Sharmin, Jiban Podder

Abstract

Undoped and manganese (Mn)-doped zinc oxide (ZnO) thin films have been deposited onto glass substrates at 300 C using a low cost spray pyrolysis technique. Structural, optical and electrical properties of the as-deposited films have been investigated. Scanning electron microscopy images show the existence of clusters with well-defined nucleation centers consisting of highly dense ganglia-like fibers over a large area around the nucleation center. Chemical compositions of the ZnO and Mn-doped ZnO thin films are studied by using energy dispersive X-ray (EDX) analysis. X-ray diffraction spectra depict that the films have polycrystalline wurtzite structure. The average crystallite sizes are calculated in the range of 8 -16 nm by Williamson–Hall method and found in good agreement with Scherer method. Optical transmittance of the films is about 80% in the visible region. Bandgap energy is tuned to 2.83 eV from 3.10 eV with increasing Mn doping. Electrical resistivity at room-temperature decreases significantly with increasing Mn doping as well as increasing temperature from 300–440 K. The activation energies in the temperature ranges 300–350 K and 350 - 440 K are found to be in the range of 0.25–0.16 eV and 0.35–0.59 eV, respectively. Hall Effect measurements show that the thin films have negative Hall co-efficient indicating nn-type conductivity at room-temperature. Carrier concentration is found to be of the order of 1018 cm−3.

Effect of M (Ni, Cu, Zn) doping on the structural, electronic, optical, and thermal properties of CdI2: DFT based theoretical studies

Md. Abdul Momin, Md. Aminul Islam, Meherun Nesa, Mehnaz Sharmin, Mohammad Jellur Rahman and A. H. Bhuiyan

Abstract

Structural, electronic, optical, and thermal properties of undoped and metal,M(Ni, Cu, and Zn), doped cadmium iodide (CdI2) were studied using a generalized gradient approximation of density functional theory. Lattice constants found from the theoretical studies of the structure of the undoped and doped CdI2 are in good agreement with those found in the available experimental and theoretical investigations. A strong mixing of I 5p and M 3d states is found after the doping of 3d M in CdI2, which alters the bandgap from positive to negative. Among all M (Ni, Cu, and Zn), Ni doped CdI2 with a narrow negative bandgap evolve the quantum dot level. Due to interactions between the Cd 4d and M 3d states, the measured optical and thermal properties of the doped system assessed with pure CdI2 indicate unusual behaviors, which suggest that the material can be used in different nano-electronic and electrochemical applications and in biological levels such as detection
of COVID-19 pathogens.

Influence of substrate temperature on the morphological, structural, optical and electrical properties of nanostructured CuO thin films synthesized by spray pyrolysis technique

P. Datta, M. Sahrmin, J. Podder, S. Choudhury

Abstract

Nanostructured copper oxide (CuO) thin films have been synthesized onto the glass substrates from aqueous solutions of copper (II) acetate monohydrate precursor salt by a cost effective spray pyrolysis technique at various substrate temperatures between 473 and 673 K. The effects of varying substrate temperature on the structure, surface morphology, optical and electrical properties of the synthesized CuO thin films were studied. Scanning Electron Microscopic (SEM) images revealed agglomerated nanoparticles on the surface of CuO thin films. X-Ray Diffraction (XRD) analysis revealed monoclinic structure with the predominant (̅111) orientation of the synthesized films. Crystallite size increased (9.15 to 10.29 nm) with the increase of substrate temperature. In UV-vis-NIR spectroscopy, CuO thin films showed higher transparency in the NIR region. An optical band gap of CuO thin film was found in the range of 2.04 - 2.49 eV. Transmittance and band gap decreased with the increase of substrate temperature up to 573 K and found to increase at 673 K. On the other hand, extinction coefficient and refractive index increased with the increase of substrate temperature up to 573 K and decreased afterwards. Electrical resistivity of CuO thin films was found in the range 1.16 ×103 - 4.61 ×103 Ω-m and decreased with the increment of the substrate temperature up to 573 K. Activation energies of CuO thin film were found in the range 0.08 - 0.57 eV. Hence, we report the influence of substrate temperature for the synthesis of nanostructured CuO thin films, best fit for optoelectronic applications.

Role of Zn dopants on the surface morphology, chemical structure and DC electrical transport properties of nanostructured p-type CuO thin films

Meherun Nesa, Mehnaz Sharmin, A.H. Bhuiyan

Abstract

This paper is based on the studies of surface morphology, chemical structure and DC electrical transport properties of zinc (Zn) doped copper oxide (CuO:Zn) thin films synthesized by spray pyrolysis technique. CuO and CuO:Zn thin films were deposited onto ultrasonically cleaned microscope glass substrates at the substrate temperature 423 K. Zn concentration (conc.) in CuO:Zn thin films was varied from 1 to 6 at%. In field emission scanning electron microscopic images of CuO:Zn thin films nanostructures are observed around the nucleation center. The maximum average particle size is found about 18 nm for 5 at% Zn doped CuO:Zn thin film. X-ray photoelectron spectroscopy confirms the chemical structure and composition of the films. Activation energy of CuO:Zn thin films in the temperature range 350 - 423 K increases from 0.17 - 0.39 eV with the rise of Zn conc. in the range of 2 - 6 at%. DC electrical resistivity of CuO:Zn thin films is found in the order of 104 Ω-cm. Hall effect measurements confirms the p-type conductivity of CuO:Zn thin films with the carrier conc. in the order of 1018 cm-3. Carrier mobility of 5 at% CuO:Zn thin film is as high as 84.83 cm2 V-1 s-1.

p to n-type transition with wide blue shift optical band gap of spray synthesized Cd doped CuO thin films for optoelectronic device applications

M. H. Babu, J. Podder B. C. Dev, M. Sharmin

Abstract

CuO thin film has a wide variety of potential applications due to distinctive optical properties and native p-type electrical conductivity. The weak p-type electrical conductivity of CuO thin film can be modified via doping suitable elements into it. In this work, we acquired n-type electrical conductivity in the CuO thin film by cadmium (Cd) doping for the first time. Pristine and Cd doped CuO thin films are fabricated at 325 ºC using a simple spray pyrolysis technique with different doping concentrations (i.e x = 0.00, 0.02, 0.04, 0.06 and 0.08). X-ray diffraction (XRD) spectra of Cd doped CuO thin films match to the polycrystalline with a monoclinic structure and no peak corresponding to Cd impurity or non-stoichiometric phases are found in the XRD pattern. Based on the XRD patterns, the average crystallite size is obtained from 15.12 to 30.53 nm. Furthermore, a closely-spaced nanoparticle is confirmed by the field emission scanning electron microscopes (FESEM). The energy dispersive analysis X-ray spectra (EDAX) demonstrate the effect of substitutions of Cu2+ ions by Cd2+ ions in the pristine CuO lattice network. Hall Effect measurements reveal that the p-type conductivity of CuO thin films alters to n-type as a result of Cd doping. The electrical resistivity of Cd doped CuO thin films upraise with the reduction of carrier concentration and increment of carrier mobility with the increase of Cd concentration in the films. An increment of transmittance and broadening of the blue shift optical band gap is possessed in CuO thin films via Cd doping and found as a promising material for a wide range of optoelectronic device applications.

Band Gap Tuning, n-type to p-type Transition and Ferrimagnetic Properties of Mg Doped α-Fe2O3 Nanostructured Thin Films

Mehnaz Sharmin and Jiban Podder

Abstract

Fe2O3 thin films have a wide range of applications in gas sensing, biosensing, optoelectronics, spintronics, etc. In this paper, pure and Mg doped Fe2O3 thin films are prepared onto glass substrates by a simple chemical spray pyrolysis technique. Cubic and rectangular cuboid shaped nanocrystals are observed in the FESEM images of the films up to 6 at% Mg concentration. XRD patterns of Mg doped Fe2O3 thin films match with the corundum structure showing the predominance of (104) orientation. Crystallite size increases from 29 to 87 nm with the increase of Mg concentration in the films. Raman spectroscopy indicates that Mg doped Fe2O3 thin films consist of only pure hematite or α-Fe2O3 phases. Chemical composition of the films are confirmed by energy dispersive X-ray analysis. Optical transmittance and band gap rise with the uplift of Mg concentrations. The maximum transmittance is found to be 83% for 10 at% Mg doped Fe2O3 thin film. In the photoluminescence spectroscopy, green emission is dominant up to 6 at% Mg doping and dominance of blue emission is observed in the 8 and 10 at% Mg doped Fe2O3 thin films. The n-type electrical conductivity of Fe2O3 changed into p-type for 6, 8 and 10 at% Mg doping. Electrical resistivity is found in the order of 105 Ω-cm which rises with Mg concentration. Pure Fe2O3 thin film shows ferromagnetic nature, whereas Mg doped Fe2O3 thin films show ferrimagnetic nature at room temperature. Mg doped Fe2O3 thin films may be suitable for sensing purposes and high power devices.

Structural, optical and electronic properties of CuO and Zn doped CuO: DFT based First-principles calculations

Meherun Nesa, Md. Abdul Momin, Mehnaz Sharmin, A.H. Bhuiyan

Abstract

Density functional theory based First-principles calculations have been performed to investigate the structural, optical and electronic properties of CuO and Zn doped CuO and compared with experimental results. Calculations are demonstrated by Cambridge Serial Total Energy Package. Calculated values of lattice parameters matched 80% with experimental data of CuO and for Zn doped CuO, there was a 55% match. Figures of electronic band structure, TDOS and PDOS have been computed from the electronic structure of CuO and Zn doped CuO. Significant transition occurs in band gap after Zn doping. Optical properties showed that CuO and Zn doped CuO were transparent, having a small energy gap and maximum reflectivity at infrared region. The real part of refractive index was higher at lower energy region and imaginary part of refractive index was zero at 28 eV photon energy. The calculated value of band gap was in good agreement with the experimental value.

Influence of Al Doping on the Structure and Properties of Fe2O3 Thin Films: High Transparency, Wide Band Gap, Ferromagnetic Behavior

Mehnaz Sharmin and Jiban Podder

Abstract

This paper is based on detailed study of structural, morphological, optical, transport and magnetic properties of aluminum (Al) doped ferric oxide (Fe2O3) thin films deposited onto glass substrates at 350 ºC by spray pyrolysis technique. Al concentration was varied from 0 to 10 atomic percentages (at%). The X-ray diffraction patterns of Al doped Fe2O3 thin films showed the corundum structure with the predominant (104) peak. In scanning electron micrographs, the surfaces of the Al doped Fe2O3 thin films were observed to be formed of nanoparticles. Al doped Fe2O3 thin films were transparent in visible to near infrared region. Transmittance and optical band gap of Al doped Fe2O3 thin films increased with the rise of Al concentration up to 6 at% and then decreased for the 8 and 10 at% Al concentrations. Al doped Fe2O3 thin films showed n-type electrical conductivity with high mobility and Hall coefficient. Electrical resistivity of Al doped Fe2O3 thin films varied from 5.67  105 to 8.92  105 Ω-cm and carrier concentration was found between 1.56  1017 and 8.64  1017 cm-3. Hysteresis loops of Al doped Fe2O3 thin films recorded at room temperature matched the nature of soft ferromagnetic materials and the saturation magnetization decreased with Al concentration in Fe2O3 thin films.

Modifications in structure, surface morphology, optical and electrical properties of ZnO thin films with low boron doping

Mehnaz Sharmin & A. H. Bhuiyan

Abstract

Boron doped zinc oxide (ZnO:B) thin films with low B concentration, varied between 0.50 and 1.50 atomic percentages (at%) are prepared at substrate temperatures (TS) between 300 and 450 °C using spray pyrolysis technique. Polycrystalline wurtzite structure is observed in the X-ray diffraction patterns of ZnO:B thin films, where (002) is the predominant peak. Texture coefficient corresponding to (002) peak increases with B concentration from 0.50 to 1.00 at%. Crystallite size is found between 22 and 64 nm. Nanofibrous surface morphology is observed in the field emission scanning electron microscopic images of ZnO:B thin films. The average nanofiber thickness value varies from 198 to 498 nm. Atomic force microscopic images show the nanotip-like topology of ZnO:B thin films. The average surface roughnesses of the films are found in the range of 2.99–12.45 nm. ZnO:B thin films are found to be highly transparent between visible to near infrared region of the electromagnetic spectrum. The highest transmittance of 87% is noticed for the 1.00 at% ZnO:B thin film prepared at the TS of 450 °C. Optical band gaps of ZnO:B thin films vary between 3.15 and 3.31 eV. 1.00 at% ZnO:B thin films prepared at various TS show lower values of the band gap, refractive index and extinction coefficient at the photon wavelength of 750 nm. Electrical resistivity of ZnO:B thin films are found to be between 0.25 × 104 and 1.39 × 104 Ω m. 1.00 at% ZnO:B thin films prepared at various TS show less electrical resistivity. Arrhenius plots of ZnO:B thin films prepared at various TS show two conduction regions and activation energies of ZnO:B thin films are higher for the films deposited at lower TS. ZnO:B thin films show n-type conductivity and carrier concentration increases with the increase of B concentration.

Influence of Substrate Temperature on the Properties of Spray Deposited Nanofibrous Zinc Oxide Thin Films

Mehnaz Sharmin & A. H. Bhuiyan

Abstract

Zinc oxide (ZnO) thin films were deposited onto glass substrates by a spray pyrolysis technique at the substrate temperatures (T S) between 250 and 500 °C. T S was observed to be one of the key parameters to influence the structural, surface morphological, optical and transport properties of ZnO thin films. X-ray diffraction patterns of the ZnO thin films showed polycrystalline hexagonal wurtzite structure and the preferred orientation was along (002) plane which got more prominent with the increase of T S. Field emission scanning electron microscopy of ZnO thin films showed the existence of nanofibers in the films with the average thickness ranging from 308 to 540 nm. Atomic force microscopy revealed that roughness of the ZnO thin film increased at higher T S. ZnO thin films were highly transparent in the visible to near infrared region with the maximum transmittance of 89% and the optical band gap was found from 3.23 to 3.31 eV. ZnO thin films showed n-type conductivity with the carrier concentrations ranging between 1019 and 1020 cm− 3. ZnO thin film deposited at the T S of 400 °C showed the highest mobility, highest carrier concentration and less resistivity.

Structural, Morphological, Optical and Electrical Properties of Spray Deposited Zinc Doped Copper Oxide Thin Films

Meherun Nesa, Mehnaz Sharmin, K. S. Hossain & A. H. Bhuiyan

Abstract

Nanostructured spray deposited zinc (Zn) doped copper oxide (CuO) thin films were characterized by employing X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy. XRD patterns of CuO and Zn doped CuO thin films indicated monoclinic structure with the preferred orientation along (1¯11)(1¯11) plane. Maximum value of crystallite size is found about 28.24 nm for 5 at% Zn doped CuO thin film. In FESEM images, nanoparticles were observed around the nucleation center. EDX analysis confirms the presence of all component elements in CuO and Zn doped CuO thin films. Analysis by AFM of CuO and Zn doped CuO thin films figured out decrease of surface roughness due to Zn doping. UV–Vis–NIR spectroscopy showed that CuO and Zn doped CuO thin films are highly transparent in the NIR region. Optical band gap of CuO thin films decreased with substrate temperature and that of Zn doped CuO thin films increased with Zn concentration. Refractive index of CuO and Zn doped CuO thin films raised with photon wavelength and became constant in the NIR region. 5 at% Zn doped CuO thin film showed the highest optical conductivity and the lowest electrical resistivity at room temperature.

Effect of Doping Concentration on the Optical Properties of Indium-Doped Gallium Arsenide Thin Films

Md. Saiful Islam, Chitra Das, Mehnaz Sharmin, Kazi Md. Amzad Hussain & Shamima Choudhury

Abstract

Effects of indium doping (concentration 0.2, 0.3 and 0.4%) on the optical properties of GaAs thin films were studied. Thin films of 600 nm were grown onto chemically and ultrasonically cleaned glass substrate by thermal evaporation method in high vacuum (~10-4 Pa) at 50°C fixed substrate temperature. The samples were annealed for 15 minutes at a fixed temperature of 200°C. The thicknesses of films were being measured in situ by a quartz crystal thickness monitor during deposition. The transmittance and reflectance data were found using UV-VIS-NIR spectrophotometer in the photon wavelength range of 310 ~ 2500 nm. These data were utilized to compute the absorption coefficient, refractive index, extinction co-efficient and band gap energy of the studied films. Here transmittance was found 78 for 0.2% indium doping concentration. The band gap energy decreased with the increase of doping concentration.

Structure, Morphology and Opto-Electrical Properties of Nanostructured Indium Doped SnO2 Thin Films Deposited by Thermal Evaporation

Md. Mahafuzur Rahaman, Kazi Md. Amjad Hussain, Mehnaz Sharmin, Chitra Das & Shamima Choudhury

Abstract

Indium doped Tin oxide (SnO2: In) thin films of various thicknesses (200-600 nm) with fixed 2% indium (In) concentration were prepared by thermal evaporation method onto glass substrates under high vacuum (10-6 Torr). As deposited films were vacuum annealed at 200o C for 60 minutes. The structure, optical, electrical and morphology properties of SnO2: In thin films were investigated as a function of film thickness. The XRD analysis revealed that films were polycrystalline in nature with a tetragonal structure having (110) plane as the preferred orientation. The average crystalline size increased from 34.8 to 51.25 nm with increase of film thicknesses. The surface morphology of the doped films was obtained by Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM). Optical transmittance was obtained from a double beam UV-Vis- NIR spectrophotometer. Maximum transmittance varied from 65-76% in the visible range of the spectrum. Optical band gap (Eg) varied between 2.89 and 3.20 eV. The resistivity of SnO2: In thin films was as high as 105 Ω-cm. Activation energy of the films were found to be 0.18 to 0.47 eV for 300-600 nm film thicknesses. Due to high optical band gap and high electrical resistivity, these nanostructured films can be used in optoelectronic devices especially as opto-insulator.

Structural and Optical Characterization of Magnesium Doped Zinc Oxide Thin Films Deposited by Spray Pyrolysis

Mitali Biswas, Mehnaz Sharmin, Chitra Das, Shamima Choudhury & Jiban Poddar

Abstract

Pure and magnesium (Mg) doped zinc oxide (ZnO) thin films were prepared onto clean glass substrate by spray pyrolysis (SP) technique at the
substrate temperature of 300°C. Various optical parameters such as absorption co-efficient, band gap energy, refractive index, extinction coefficient
of the thin films were studied using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300-2500 nm. Optical band
gap increased from 3.24 to 3.46 eV with the increase of Mg concentration from 0 to 40%. Transmittance and refractive index of the Mg doped
ZnO thin films decreased due to the increase of Mg concentration. The EDX spectra confirmed the increase of Mg and consequent reduction in
Zn content in the Mg doped ZnO thin films. Pure and Mg- doped ZnO films were annealed at 425°C for 1 hour. X-ray diffraction (XRD) study
of the annealed films showed hexagonal type of polycry-stalline structure with the preferred orientation along (101) plane with some other
peaks (100), (002), (102), (110), (103) and (112). From the XRD patterns it was found that grain size decreased from 63.45 to 36.56 nm, lattice
constant  and c remained almost constant with Mg doping concentration.

Optical and Structural Properties of p-Type Silicon

Mehnaz Sharmin, Shamima Choudhury & Tahmina Begum

Abstract

Electrical, optical and structural properties of p-type single crystal silicon were investigated in this work. Electrical conductivity of p-type silicon was measured in the temperature ranges 190 - 300 K. The acceptor ionization energy (􀀀E A) was between 0.047 - 0.051 eV.
Photoconductivity of the material was investigated by varying sample current, light intensity and temperature at a constant chopping frequency of 45.60 Hz. Absorption co-efficient (􀀀) of the material was calculated from optical transmittance and reflectance measurements
at room temperature (300 K) in the wavelength range of 300 -2500 nm. The direct optical band gap energy was found between 2.10 - 2.20 eV and the indirect optical band gap energy was found between 0.95 – 1.0 eV. The lattice parameter (a) was found to be 5.419Å from X-ray diffraction method (XRD).

STRUCTURAL AND OPTICAL CHARACTERIZATION OF VACUUM EVAPORATED ZINC SELENIDE THIN FILMS

Andalipa Islam, Chitra Das, Shamima Choudhury, Mehnaz Sharmin & Tahmina Begum

Abstract

Optical and structural characterization of Zinc Selenide (ZnSe) thin films (thickness ranging between 200 - 500 nm) prepared by vacuum (~10-6 Torr) evaporation method were investigated. The thin films were deposited with varying substrate temperature in the range 373 - 573K. Optical measurements were carried out with UV-VIS-NIR spectrophotometer with photon wavelength ranging between 300-2500 nm. The absorption coefficient, energy band gap, refractive index and extinction coefficient were determined using transmission and reflection spectra at the same wavelength range. The dependence of absorption coefficient in the photon energy had been determined. Analysis showed that direct transition occured with band gap energies ranges from 2.6 eV to 2.9 eV. Refractive indices and extinction coefficients were evaluated in the above spectral range. For structural properties, 300nm films were deposited with varying substrate temperatures and were vacuum annealed in situ at 373 K for one hour. The X- ray diffraction (XRD) patterns showed polycrystalline nature of films having cubic (Zinc blende) structure. The most preferential orientation is along [111] direction for all deposited films together with other abundant planes [220] and [311]. Structural parameters such as lattice constant, grain size, internal stress, microstrain, dislocation density were calculated. The value of lattice constant was estimated to be5.660 Å to 5.761 Å.. The grain sizes were calculated to be which ranges between 266 Å to 384 Å. With the increase of substrate temperature the average grain size of the ZnSe films increases, asrevealed from the XRD studies.

OPTICAL AND TRANSPORT PROPERTIES OF p-TYPE GaAs

Mehnaz Sharmin, Shamima Choudhury, Nasrin Akhtar & Tahmina Begum

Abstract

Electrical properties such as electrical resistivity, Hall coefficient, Hall mobility, carrier concentration of p-type GaAs samples were studied at room temperature (300 K). Resistivity was found to be of the order of 5.6 × 10-3Ω-cm. The Hall coefficient (RH) was calculated to be 7.69 × 10-1cm3/C and Hall mobility (μH) was found to be 131cm2/V-s at room temperature from Hall effect measurements. Carrier concentration was estimated to be 8.12 × 1018/cm3 and the Fermi level was calculated directly from carrier density data which was 0.33 eV. Photoconductivity measurements were carried on by varying sample current, light intensity and temperature at constant chopping frequency 45.60 Hz in all the cases mentioned above. It was observed that within the range of sample current 0.1 - 0.25mA photoconductivity remains almost constant at room temperature 300K and it was found to be varying non-linearly with light intensity within the range 37 - 12780 lux. Photoconductivity was observed to be increasing linearly with temperature between 308 and 428 K. Absorption coefficient (α) of the samples has been studied with variation of wavelength (300 - 2500 nm). The value of optical band gap energy was calculated between 1.34 and 1.41eV for the material from the graph of (αhν) 2 plotted against photon energy. The value of lattice parameter (a) was found to be 5.651Å by implying X-ray diffraction method (XRD).

Structural, morphological, optical and electrical properties of Co doped CuO thin films

R. Rahaman , M. Sharmin and J. Podder

Abstract

Copper (II) oxide (CuO) is a semiconductor with p-type conductivity and monoclinic structure. Availability in nature, environment friendly behavior, band gap in the visible region of light and ability to form porous microstructure has made CuO an interesting material to the researchers. In recent years, transition metal-doped CuO thin films have been prepared using several deposition techniques and the properties of the films have been studied by the scientific community for device applications. In this work, cobalt (Co)-doped CuO thin films have been synthesized using a simple and low-cost spray pyrolysis technique. CuO films have been prepared with the Co concentrations 0, 2, 4, 6 and 8 at%. Field emission scanning electron microscopic images of Co-doped CuO thin films, show the aggregations of nanoparticles on the film surfaces. For 6 at% Co doping, the surface morphology of CuO turns into porous and sponge-like nanostructures. In X-ray diffraction analysis, CuO film shows monoclinic structure with the preferential orientation along (11) direction. No other peak corresponding to Co impurity or any other crystalline phase of copper oxide are found up to 4 at% of Co doping. The (11) peak loses its predominance with the appearance of the (311) peak corresponding to Co3O4 and (200) peak related to Cu2O upon 6 and 8 at% Co doping. The crystallite size decreases from 11 to 5 nm with Co doping. In UV-visible spectroscopy, the optical transmittance of Co-doped CuO films increases with wavelength and saturates in the near-infrared light region. The highest transmittance of about 96% is found for the 6 at% Co- doped CuO film. The optical band gap of the films increases from 2.14 to 2.91 eV with Co doping. Refractive index, dielectric constants, and electron effective mass reduces with Co doping. Electrical resistivity of the films decreases with Co doping. The films shows p-type conductivity up to 2 at% Co doping, then for further doping the conductivity changes into n-type with the reduction of Hall coefficient and carrier mobility. Remarkable changes occur in the structural, morphological, optical and electrical properties of CuO thin films because of Co doping. It may be said that Co-doped CuO thin films can be used for optoelectronic applications.

Structural, Morphological, Optical, and Electrical analysis of Mn-doped NiO Thin films

S. A. Lucky, M. Sharmin, H. Das, M. S. Bashar and J. Podder

Abstract

Nickel oxide (NiO) is a semiconductor with face-centered cubic (fcc) crystal structure. Because of the wide band gap, high transparency, and porous surface morphology of NiO, it shows high-performance in various electronic and optoelectronic devices. For this reason, recently metal doped NiO thin films has drawn the attention of the researchers. In this work, NiO and manganese (Mn) doped NiO thin films have been deposited onto glass substrates at 723 K temperature using a simple and low-cost spray pyrolysis technique. The amount of Mn doping is varied from 0 to 4 at% at the step of 1 at% in NiO films. Structure, morphology, chemical composition as well as the optical and electrical properties of the deposited films are studied. X-ray diffraction analysis shows that NiO and Mn-doped NiO films has fcc structure with the predominance of (111) peak. Crystallite size decreases from 31 to 22 nm with Mn doping. Surface morphology was investigated by a scanning electron microscope (SEM). In SEM images all the samples show uniform distribution of particles with porous structure. Chemical composition and stoichiometry the deposited thin films have been confirmed by Energy dispersive X-ray spectroscopy. The optical transmittance is measured in the wavelength range 200 - 1100 nm using an UV-Visible spectrophotometer. Highest transparency around 90% and band gap of 4.03 eV is obtained for 2 at% Mn-doped NiO thin film. Extinction coefficient and dielectric loss tangent in the visible-NIR region of light reduce with Mn doping. 1 at% Mn doped NiO film shows the highest optical conductivity and refractive index in the visible light. The room temperature resistivity increases with Mn-doping up to 2 at%. Investigation of the temperature dependent electrical conductivity reveals that almost all the films show three regions of conduction except the 2 at% Mn-doped film. Two regions of conductivity are found for 2 at% Mn-doped NiO thin film. The activation energies are calculated in the temperature range of 300 - 373 K. All the samples show low activation energy at the higher temperature regions. Formation of transparent and crystalline NiO thin films with porous surface morphology, wide band gap, high resistivity and low activation energy via Mn-doping indicated the suitability of this material in fabrication of sensors and high-power devices.    

Structural and optical properties of manganese doped nickel oxide thin films

Selina Akter Lucky, Mehnaz Sharmin, Harinarayan Das and Jiban Podder

Abstract

Nickel oxide (NiO) is a p-type metal oxide semiconductor with a band gap in the range of 3.60 – 4.00 eV. In this work, a simple and low-cost spray pyrolysis technique was used for the deposition of NiO thin films with 0, 1, 2, 3, and 4 at% manganese (Mn) concentrations. In the X-ray diffraction (XRD) analysis of the films, peaks correspond to (002), (111), (200), (220), (311) and (222) crystalline planes appeared. The films exhibited face-centered cubic (fcc) structure with the predominance of (111) peak. The intensity of (111) peak maximized for 1 at% Mn doping in NiO indicating improvement in crystallinity in comparison with NiO film. No other peaks corresponding to Mn impurities were found in the XRD analysis. No further improvement was found in crystalline structure upon 4 at% Mn doping. The optical properties of the deposited films were studied in the spectral range 300 – 1100 nm using a UV-vis spectrophotometer. NiO and Mn-doped NiO films were transparent in the visible and near infrared region. The transmittance of the film increased significantly with Mn doping. The transmittance of 2 at% Mn doped NiO film reached a maximum of about 87%, which is much higher than the maximum transmittance of NiO film. The optical band gap of the films was in the range of 3.17- 4.03 eV. The maximum band gap was found for 2 at% Mn doped NiO thin film. The increase of transparency and optical band gap indicates the applicability of this material in the field of optoelectronics devices.

Investigation of structural, optical and electrical properties of calcium substituted barium titanate thin films for various optoelectronic applications

A. Barik, A. Ahad, M.H. Babu, J. Podder and M. Sharmin

Abstract

Thin films of Ba1-xCaxTiO3 with various calcium (Ca) contents (x = 0, 2, 4, 6, and 8 at.%) were successfully synthesized onto the glass substrate by a thermal spray pyrolysis technique. Field emission scanning electron microscopy images revealed that the average grain size varies from 1.38 to 4.95 μm. The presence of all the elements was confirmed by energy dispersive X-ray analysis. The X-ray diffraction analysis confirmed the formation of the hexagonal phase of as-deposited samples. The crystallite sizes were found to reduce from 189 to 116 nm as a result of Ca doping. Atomic force microscopy indicated surface roughness varies from 86 to 187 nm. The 2 at.% Ca doped thin films exhibited transparency of about 47%. From the UV-visible spectra, an increment of optical conductivity is calculated from 2.9 to 7.3 s-1. The optical band gap varies from 3.90 to 3.80 eV with the increase of Ca substitution. The electrical resistivity of the films decreased from 11.95×103 to 7.54×103 Ωm with increasing Ca content. Nanostructured thin films with uniform surfaces and well-distributed grains are grown in the present research. The results obtained from Ba1-xCaxTiO3 thin films could be useful for various optoelectronic applications.  

Abstract

Zinc oxide (ZnO) and boron (B) doped ZnO thin films were deposited onto microscope glass slides by spray pyrolysis technique. The amount of B doping was varied between 1 and 5 at% in ZnO thin films. An evolution in surface morphology from nanofibrous to nanoflakes pattern has been observed in B doped ZnO thin films by field emission scanning electron and atomic force microscopies images. The chemical structure and composition of the films are confirmed by Energy dispersive X-ray and X-ray photoelectron spectroscopy analyses. The films show a polycrystalline wurtzite structure with the preferential (002) orientation in X-ray diffraction analysis. Crystallite size is found in the range of 18 to 32 nm. The films are transparent in the Vis-NIR region and the optical band gap is found between 3.20 and 3.29 eV. Direct current electrical resistivity and carrier concentration of B doped ZnO thin films are found in the order 10-2 Ω-cm and 1020 cm-3, respectively. The films show a change of majority charge carriers from n-type to p-type for 5 at% B doping. The highest carrier mobility is found to be 1.44 cm2V-1s-1 for 1 at% B doped ZnO thin film. The results of various investigations presented in the paper suggest the suitability of B doped ZnO thin films in optoelectronic applications. 

Modifications in structure and optical-electrical properties of cupric oxide thin films doped with manganese

P. Datta, M. Sahrmin, J. Podder, S. Choudhury

Abstract

Cupric oxide (CuO), an environment friendly p-type transition metal oxide was studied in undoped and doped nanostructured forms by researchers for several potential applications such as solar cells, transistors, gas sensors, etc. In this work, manganese (Mn) doped CuO thin films were prepared onto glass substrates at the substrate temperature of 523 K using spray pyrolysis technique. The amount of Mn concentration was varied from 0 to 6 at% in CuO thin films. The prepared samples were annealed at 723 K in the air for 1 hour. The film surface was observed to be comprised of aggregations of nanoparticles in the Scanning Electron Microscopic images. Elemental composition of the films was confirmed by Energy Dispersive X-ray analysis. The as-deposited films showed amorphous structure, whereas the annealed films showed monoclinic structure with the preferential orientation along ( 1 11) and (111) planes. Crystallite size was found between 10 and 19 nm. Optical properties were measured using a UV-vis spectrophotometer. Transmittance of CuO thin film increased with Mn concentration in the visible-infrared region of light. Optical band gap of the films broadened from 2.09 to 2.45 eV with increase in Mn doping. Electrical resistivity of the samples raised from 0.64×103 to 1.62×103 Ω-m with the increase of Mn doping. The films showed two regions of electrical conduction in the temperature ranges 383 - 423 K and 323 - 383 K, respectively. Activation energy varied from 0.08 to 0.29 eV in the temperature ranges 323 - 383 K, whereas it varied from 0.29 to 0.40 eV in the temperature ranges 383 - 423 K. The results suggest that Mn doped CuO thin films can be suitable for optoelectronic devices.

Studies on the Topographical and Photoluminescence Properties of Mg Doped Fe2O3 Thin Films

M. Sharmin, J. Podder and K. S. Hossain

Abstract

Magnesium (Mg) doped Ferric oxide (Fe2O3) thin films were synthesized onto soda lime glass substrates at the temperature of 350 ℃ by the thermal spray pyrolysis technique. Mg doped Fe2O3 thin films were prepared with 0, 2, 4, 6, 8 and 10 at% Mg concentrations. Mg doped Fe2O3 thin films are found to have porous surface with uniform distribution of peaks and valleys in atomic force microscopy images. The average roughness of Mg doped Fe2O3 thin films increases in the range 11 to 66 nm with Mg concentration. X-ray diffraction spectra of Mg doped Fe2O3 thin films show that the films have corundum structure with preferential (104) peak. Mg doping causes shifting and splitting of (104) peak due to the generation of lattice asymmetry in Fe2O3 structure. Raman spectroscopy of Mg doped Fe2O3 thin films shows the presence of hematite phases in the range of wavenumber 200 - 1320 cm-1. The optical band gap widens from 2.11 - 2.75 eV with the increase of Mg concentration. Refractive index and extinction coefficient at the wavelength 750 nm decreases with Mg concentration. Photoluminescence (PL) property of Fe2O3 thin film is enhanced via Mg doping and that promotes the blue emission in Fe2O3 thin films. Band gap widening is also evident from the PL spectra. The exclusive topographical features, improved crystalline structure, broadened band gap and enriched PL behavior of Mg doped Fe2O3 thin films suggest its suitability in the fabrication of optoelectronic devices.

Structural, Morphological, Optical and Electrical Properties of ZnO/SnO2 Thin Films Synthesized by Thermal Spray Pyrolysis Technique for Optoelectronic Applications

W. B. Tarique, Mehnaz Sharmin and J. Podder

Abstract

Influence of Mg doping on The Electrical Transport Mechanism, Optical and Magnetic Properties of Fe2O3 Thin Films

Mehnaz Sharmin & Jiban Podder

Abstract

Ferric oxide (Fe2O3) is an intrinsic n-type semiconductor having a wide band gap and environment friendly nature. Magnesium (Mg) is one of the p-type dopants used to enhance electrical conductivity of Fe2O3. In this work, Mg doped Fe2O3 thin films were synthesized with 0, 2, 4, 6, 8 and 10 at% Mg concentrations by a simple spray pyrolysis technique. The surface of the films comprised of uniformly distributed nanoparticles along with some cubic shaped nanocrystals, which were found up to 6 at% Mg doping. Corundum structure with the favored orientation along (104) plane is found in the X-ray diffraction patterns of Mg doped Fe2O3 thin films. Raman spectra of Fe2O3 thin films showed the existence of pure α-Fe2O3 or hematite phases in the film, which mostly disappeared after 10 at% Mg doping. Transmittance of Mg doped Fe2O3 thin films increased with the rise of Mg concentration. The maximum transmittance was about 83 %, found in 10 at% Mg doped Fe2O3 thin films. The optical band gap widened from 2.14 to 2.75 eV with the increment of Mg concentration up to 8 at%. The room temperature electrical resistivity of Mg doped Fe2O3 thin films increased from 4.9 × 105 - 12.2 × 105 Ω-cm with the increase of Mg concentration. The n-type conductivity of Fe2O3 thin film is changed to p-type above 6 at% Mg doping and carrier mobility decreased with the raise of Mg concentration. The hysteresis loop of Mg doped Fe2O3 thin films recommended that Mg doping softened the ferromagnetic properties of Fe2O3. The unique surface morphology, better crystallinity, high transparency, wide band gap, p-type conductivity and ferromagnetic behavior of Mg doped Fe2O3 thin films recommended its versatile use in manufacturing optoelectronic devices.

The Effect of Al on the Structural, Morphological, Topological, Optical, Transport and Magnetic Properties of Fe2O3 Thin Films

Mehnaz Sharmin, Jiban Podder and K. S. Hossain

Abstract

Ferric oxide (Fe2O3) is a large band gap material having the versatility of applications in various devices. Aluminum (Al) is a popular dopant used for Fe2O3 to modify the structure and properties of the material. In this work, Al doped Fe2O3 thin films were prepared onto clean glass substrates at the substrate temperature of 350 °C with 0, 2, 4, 6, 8 and 10 at% Al concentration by spray pyrolysis technique. Field emission scanning electron microscopy and atomic force microscopy images showed the presence of nanoparticle agglomerates and regular distribution of pores covering the scanned areas of Al doped Fe2O3 thin films. X-ray diffraction patterns of Al doped Fe2O3 thin films showed polycrystalline Corundum structure with a predominant orientation along (104) plane, which disappeared at 10 at% Al doping. Raman spectroscopy of Fe2O3 thin films suggested the presence of pure α-Fe2O3 or hematite phases in the film. Optical transmittance of Al doped Fe2O3 thin films increased with the rise of Al concentration up to 6 at% and the maximum transmittance was found to be 87 %. The optical band gap increased from 2.19 to 2.98 eV with the increment of Al concentration up to 6 at%. The room temperature electrical resistivity of Al doped Fe2O3 thin films was found between 5.90 x 105 and 8.92 x 105 Ω-cm. Al doped Fe2O3 thin films showed n-type electrical conductivity and carrier concentration in the order of ~ 1017 cm-3 in Hall effect measurements. Ferromagnetic properties of Fe2O3 thin films were softened upon Al doping. Homogeneous surface, regular distribution of pores, better crystalline structure, high transparency, wide band gap, n-type conductivity and ferromagnetic behavior of Al doped Fe2O3 thin films recommends its suitability in optoelectronic devices.

Structural, Morphological, Optical and Electrical Properties of Al:Fe2O3 Nanoparticle Thin Films Synthesized for Gas Sensing Applications,

Mehnaz Sharmin & Jiban Podder

Abstract

Effect of Mg Incorporation on the Structural, Morphological, Optical, Electrical and Magnetic Properties of Ferric Oxide Nanoparticle Thin  Films

Mehnaz Sharmin & Jiban Podder

Abstract

Wide Band Gap and High Optical Transparency in Mg Doped Fe2O3 Thin Films: A Suitable Candidate for Optoelectronic Devices

Mehnaz Sharmin & Jiban Podder

Abstract

Versatility of Spray Pyrolysis Technique for Synthesis of Multilayer Metal Oxide Thin Films

W. B. Tarique, Mehnaz Sharmin and J. Podder

Abstract

Sol-gel Spin Coating: A Promising Technique for Preparation of Multilayer Metal Oxide Thin Films for Optoelectronic Applications

N. Biswas, Mehnaz Sharmin and J. Podder

Abstract

Nanostructure and Opto-electrical Properties of Temperature Dependent Indium Doped Tin Oxide Thin Films

M.M. Rahaman, K.M.A. Hussain, Mehnaz Sharmin and S. Choudhury

Abstract

The Influence of Al Doping on the Physical Properties of Fe2O3 Nanoparticle Synthesized by Chemical Spray Pyrolysis for Optoelectronic Applications

Mehnaz Sharmin & Jiban Podder

Abstract

Investigation of Structural, Morphological, Optical and Electrical Properties of Spray Synthesized Fe2O3 Thin Films for Optoelectronic Applications

Mehnaz Sharmin, M Zahan and J Podder

Abstract

Effect of Al Doping on Physical Properties of Sprayed α-Fe2O3 Nanoparticle Thin Films Synthesized for Optoelectronic Applications

Mehnaz Sharmin & Jiban Podder

Abstract

Investigation of Structure, Morphology, Optical and Electrical Properties of Sprayed ZnO Thin Films Deposited at Various Substrate Temperatures

Mehnaz Sharmin & A. H. Bhuiyan

Abstract

Characterization of Spray Pyrolized CuO Thin Films Depostied at Various Substrate Temperatures

Meherun Nesa, Mehnaz Sharmin, K. S. Hossain & A. H. Bhuiyan

Abstract

Role of Substrate Temperature on the Opto-electrical Properties of Indium Doped Tin Oxide Thin Films

Md. Mahafuzur Rahaman, Kazi Md. Amjad Hussain, Mehnaz Sharmin, Chitra Das & Shamima Choudhury

Abstract

Structural and Surface Morphological Properties of Spray Deposited CuO and Zinc Doped CuO Thin Films

Meherun Nesa, Mehnaz Sharmin, K. S. Hossain, & A. H. Bhuiyan

Abstract

Opto-Electrical Properties of Nanostructured Indium Doped Tin Oxide Vacuum Evaporated Thin Films

Md. Mahafuzur Rahaman,Kazi Md. Amjad Hussain, Mehnaz Sharmin, Chitra Das & Shamima Choudhury

Abstract

Effect of Substrate Temperature on Structural, Optical and Electrical Properties of Vacuum Evaporated Indium Doped Tin Oxide Thin Films

Md. Mahafuzur Rahaman, K. M. A. Hussain, Mehnaz Sharmin & Shamima Choudhury

Abstract

Effect of Zinc Doping on Structure and Properties of CuO Thin Films Synthesized by Spray Pyrolysis Technique

Meherun Nesa, Mehnaz Sharmin & A. H. Bhuiyan

Abstract

Influence of Boron Doping on The Structural Properties of ZnO Thin Films Deposited by Spray Pyrolysis Technique

Mehnaz Sharmin & A. H. Bhuiyan

Abstract

Electrical, Optical and Structural Properties of p-Type Silicon

Mehnaz Sharmin, Shamima Choudhury & Tahmina Begum

Abstract

Substrate Temperature Dependent Structural Properties of Thermal Evaporated ZnSe Thin Films

A.Islam, S.Choudhury, Mehnaz Sharmin, J. Begum & T. Begum

Abstract

Effect of Substrate Temperature on the Optical Properties of Vacuum Evaporated CdTe Thin Films

Mousumi Mandal, Shamima Choudhury, Chitra Das, Mehnaz Sharmin & Tahmina Begum

Abstract

Electrical and Optical Properties of p-Type GaAs 

Mehnaz Sharmin, Tahmina Begum, Nasrin Akhtar & Shamima Karim Choudhury

Abstract

Electrical conductivity of p-type single crystal Gallium Arsenide was measured in the temperature ranges 170K-300K. It was found that electrical conductivity decreases with the increase of temperature. The logarithmic graph of conductivity (lnσ) versus the inverse of temperature (in K-1) was found to be almost linear in ranges 185K-195K (below room temperature). The acceptor ionization energy (ΔE‪A) obtained from the graphs was 0.0308 eV. Photoconductivity of the same samples was also measured under different conditions. The effect of varying sample current (I), light intensity (IL) and temperature (T in K) on photoconductivity at a constant chopping frequency 45.60 Hz were investigated. It has been seen that photoconductivity increases nonlinearly with light intensity and it increases linearly with temperature. Absorption coefficient (α) of the same samples was also measured at the room temperature within the wavelength range 300 nm-2500 nm and the optical band gap energy was calculated to be 1.425 eV from the plot of (αhν) 2 versus photon energy (E).

Laboratory Personel

Dr. Mehnaz Sharmin is an active member of Prof. Dr. Jiban Podder's lab: Crystal Growth, Spray Pyrolysis & Optical Microscopy

Research Projects

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    Synthesis of Nanostructured Metal Oxide Thin Films and Construction of a Cost Effective Gas Sensitivity Testing Unit for Environmental Applications

    Co-investigator

    Synthesis of Nanostructured Metal Oxide Thin Films and Construction of a Cost Effective Gas Sensitivity Testing Unit for Environmental Applications

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    Green Synthesis and Investigation of Metal-Polymer Nanocomposites for Biomedical and Nonlinear Optical Applications

    Funding organization: Ministry of Science and Technology, Government of the People’s Republic of Bangladesh

    Project No.: 604 Phv's          

    Amount: BDT. 3,00,000/- (Three Lac Taka Only) 

    Project duration: One year. (Financial Year: 2021-2022)

    Project No.: SRG-226631     

    Amount: BDT. 4,00,000/- (Four Lac Taka Only) 

    Project duration: One year. (Financial Year: 2022-2023)

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    Green Synthesis and Investigation of Metal-Polymer Nanocomposites for Biomedical and Nonlinear Optical Applications

    Co-investigator, Funding organization: Ministry of Science and Technology, Government of the People’s Republic of Bangladesh

    Project No.

    Amount (BDT)

    Duration

    Financial Year

    604 Phv's

    3 lac

    1 year

    2021-2022

    SRG-226631

    4 lac

    1 year

    2022-2023

    SRG-236626

    2.5 lac

    1 year

    2023-2024

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