Simulation and Performance Study of Nanowire CdS/CdTe Solar Cell

Abstract

Thin film CdS/CdTe solar cell is 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 that diameter of 40-60nm is preferable for CdS nanowires for using as window layer of CdS/CdTe solar cell. 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, 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. Effects of the parameters mentioned above were observed in order to ensure high efficiency performance from nanowire CdS/CdTe solar cell.