Abdus Sobhan Bhuiyan

Bio: Abdus Sobhan Bhuiyan is an academic researcher from University of Chittagong. The author has contributed to research in topics: Latitude & Transmittance. The author has an hindex of 2, co-authored 2 publications receiving 6 citations.

Studies on optical characteristics of CuInSe2 thin films

Abstract: CuInSe2 is considered as a striking semiconductor for second generation solar cells. An investigation of optical properties of CuInSe2 thin films is essential to evaluate its perfectibility as high efficiency solar cells. The films were fabricated by thermal co-evaporation technique. For this experiment, a shimadzu spectrophotometer of model number 1201 is used. The optical properties of these films are determined for the wavelength range 350 nm–1100 nm. From the experiment it is evident that the reflectance and transmittance of the films are negligible in comparison to the absorption of these films. The high absorption coefficient of the order of 104/cm of the film material also supports this. The band gap of the CuInSe2 films was evaluated to be 1.1 eV. From XRD and EDAX analysis it is evident that CuInSe2 films are polycrystalline in nature having ideal stoichiometric composition.

Emperical Computation of Solar Radiation and Determination of Regression Coefficients for Khulna City

Abstract: This study is accomplished to calculate global, diffuse and direct solar radiation empirically on a horizontal surface for the divisional district “Khulna” in Bangladesh (latitude 22o47΄N and longitude 89o34΄E) as well as to predict correlations for it by using several meteorological data for 32 years between 1980 and 2012. The global radiation is found to be maximum in the month of April and minimum in the month of December here. The estimated values of the Angstrom’s regression constants a and b are 0.2388 and 0.5228 respectively. The other regression constants were also computed and the correlations proposed for Khulna can be used in future for the estimation of global, diffuse and direct solar radiation if the meteorological parameters remain available.

Chalcogenide compounds for solar cells

Abstract: Chalcogenides are one of the main compounds applied as absorbers of highly efficient photovoltaic devices based on thin-film technology. This chapter focuses on the concepts, structure, preparation, and the main advances on the photovoltaic properties of chalcogenide-based solar cells. The architecture of devices based on cadmium telluride, copper indium gallium diselenide, copper zinc tin sulfide, and their variations are discussed in detail. Furthermore a brief review of emerging technologies based on chalcogenides is also presented, discussing new tendencies for their use in photovoltaics.

Preparation and Characterization of Electron-Beam Evaporated Cu-lnSe Thin Films Using Two Stage Processes

Abstract: CIS (Cu-InSe) thin films were prepared onto glass substrate by the two stage process—generally called bilayer process. At first, Cu layer was deposited onto glass substrate by electron beam evaporation technique and then InSe single layer was deposited on the resulting Cu layer to produce CIS thin film. XRD (X-ray diffraction) analysis revealed that deposited film has an amorphous nature. Electrical resistivity measurements were carried out as a function of temperature during heating and cooling cycles in air. The heating and cooling cycles of the sample are almost reversible after successive heat-treatment in air. In order to consider the influence of the InSe upper layer on the optical properties, the thickness of the InSe upper layer in the CIS films was varied from 50 to 150 nm. Analysis of the transmittance and reflectance spectra, recorded in the wavelength range of 400-1,100 nm, revealed that the CIS films have high absorption coefficient of ~10 cm. The direct band gap varies from 1.40 to 1.22 eV. The refractive index, the extinction coefficient and the dielectric constant of the CIS films depend on the film thickness.

Se-loss-induced CIS Thin Films in RTA Process after Co-sputtering Using CuSe2 and InSe2 Targets

Abstract: Chalcopyrite CuInSe2 (CIS) thin films were prepared without Se- / S-containing gas by co-sputtering using CuSe2 and InSe2 selenide-targets and rapid thermal annealing. The grain size increased to a maximum of 54.68 nm with a predominant (112) plane. The tetragonal distortion parameter η decreased and the inter-planar spacing d(112) increased in the RTA-treated CIS thin films annealed at a 400°C, which indicates better crystal quality. The increased carrier concentration of RTA-treated p-type CIS thin films led to a decrease in resistivity due to an increase in Cu composition at annealing temperatures ≥ 350°C. The optical band gap energy (Eg) of CIS thin films decreased to 1.127 eV in RTA-treated CIS thin films annealed at 400°C due to the improved crystallinity, elevated carrier concentration and decreased In composition.