Electrical and Electronic Engineering

Cu2ZnSnS4 (CZTS) absorber layer research shows extensive influential factors to replace expensive Copper Indium Gallium
Selenide (CIGS) absorber layer due to its high efficiency, low-cost, non-radioactive and environmental friendly behavior.
Potential buffer layers for CZTS solar cells like ZnO, ZnS, In2S3 and ZnSe along with conventional CdS buffer layer are
numerically analyzed. Among these structures, ZnS/CZTS structure shows an optimum efficiency of 26.82% (with Voc = 0.724 V,
Jsc = 53.312 mA/cm2 and fill factor = 69.44 %).This paper explicitly reveals the most favorable CZTS layer thickness around 2.5
μm, whereas buffer layer thickness lies just below 50 nm. Absorber carrier density has its effect on Voc and Jsc and so on
efficiency. With increasing carrier density Jsc decreases while Voc increases. An optimum density of 5×1017 cm-3 to 1×1018 cm-3
shows a great result. The achieved results can lead to the development of higher efficiency CZTS thin film solar cells.
(Avoid the words in abstract Ex. Recently in this work research)

Thin film CdS/CdTe solar cells has become one of the leading technologies for providing high power conversion efficiency at comparatively low manufacturing cost. We have done modeling and simulation of thin film CdS/CdTe solar cell and then used nanowire CdS layer instead of planar CdS layer using SCAPS-1D to demonstrate the fact that the use of CdS nanowires enhances the efficiency of the CdS/CdTe solar cells by ~3%. The scattering cross section of CdS nanowire was observed using Lumerical FDTD solutions to determine the preferable diameter for CdS nanowires. For thin film CdS/CdTe solar cell the open circuit voltage was 0.69V and efficiency was 15.42%. For nanowire CdS/CdTe solar cell model the open circuit voltage was 0.82V and efficiency was 18.30%. Device parameters such as: temperature, parasitic series and shunt resistance interface state density, density of states, electron and hole mobility and metal work function were studied which can affect the efficiency of the nanowire-CdS/CdTe solar cell. The rollover effect on nanowire CdS/CdTe solar cell was explained by varying the majority carrier barrier height of back contact from 0.4 to 0.7 eV. This indicates that when the barrier height is increased, a roll over effect occurs and the efficiency decreases.

Absorption and Scattering cross section of Au/AlGaAs/GaAs single core-multishell nanowire has been analyzed using the Finite-Difference Time-Domain (FDTD) simulation. The source used in the simulation is a Total-Field Scattered-Field (TFSF) which ranged from 300-900 nm. Strong scattering cross section (σ_scat)  is observed from the σ_scat versus wavelength (λ) curve. Increase in absorption cross section is also observed due to Gallium Arsenide (GaAs) and Aluminium Gallium Arsenide (AlGaAs) having direct bandgaps. For core radii of 25 nm, 35 nm and 45 nm σ_scat increases respectively. The increase in thickness of AlGaAs layer elevated the scattering cross section far greater than the increase in thickness of the Au layer and the joint increase in thickness of the Au/AlGaAs layer increases the spectral linewidth. Shifts in wavelength (λ) is also observed as the radius of the core-multishell NW increases. Such high optical scattering properties can be used in infra-red lasing operations. Since there is a surface passivation of AlGaAs, the core multi-shell NW is also useful as photodetectors.

– Absorption and Scattering cross section of Au/AlGaAs/GaAs single core-multishell nanowire has been analyzed using the Finite-Difference Time-Domain (FDTD) simulation. The source used in the simulation is a Total-Field Scattered-Field (TFSF) which ranged from 300-900 nm. Strong scattering cross section is observed from the versus wavelength (λ) curve. Increase in absorption cross section is also observed due to GaAs and AlGaAs having direct bandgaps. For core radii of 25 nm, 35 nm and 45 nm increases respectively. The increase in thickness of AlGaAs layer elevated the scattering cross section far greater than the increase in thickness of the Au layer and the joint increase in thickness of the Au/AlGaAs layer increases the spectral linewidth. Shifts in wavelength (λ) is also observed as the radius of the core-multishell NW increases. Such high optical scattering properties can be used in infra-red lasing operations. Since there is a surface passivation of AlGaAs, the core multi-shell NW is also useful as photodetectors

Simulation has been done using SCAPS-1D to examine the efficiency of CH 3 NH 3 SnI 3-based solar cells including various HTM layers such as spiro-OMeTAD, Cu 2 O, and CuSCN. ZnO nanorod array has been considered as an ETM layer. Device parameters such as thickness of the CH 3 NH 3 SnI 3 layer, defect density of interfaces, density of states, and metal work function were studied. For optimum parameters of all three structures, efficiency of 20.21%, 20.23%, and 18.34% has been achieved for spiro-OMeTAD, Cu 2 O, and CuSCN, respectively. From the simulations, an alternative lead-free perovskite solar cell is introduced with the CH 3 NH 3 SnI 3 absorber layer, ZnO nanorod ETM layer, and Cu 2 O HTM layer.