Numerical optimization of absorber and CdS buffer layers in CIGS solar cells using SCAPS

Abstract

In this study, numerical optimization and analysis utilizing SCAPS-1D software package of CIGS solar cell structure are presented. The electrical properties and the photovoltaic performance parameters of CIGS thin film solar cells with Molybdenum as a back contact have been investigated. The possible effects of absorber CIGS and CdS buffer layers thickness, doping level and band gap energy on solar cell performance parameters are addressed. The conversion efficiency of the solar cell has been found to increase significantly with the doping concentration in the range from 10 14 to 10 18 cm -3 and absorber thickness ranging from 500 nm to 4000 nm. An optimum conversion efficiency of 21.35 % to 24.21 % has been obtained with thinner absorber thicknesses ranging from 1500 nm to 2500 nm at band gap energy of 1.15 eV and doping concentration of about 10 17 cm -3 . Moreover, the thickness of CdS buffer layer should be greater than 40 nm and less than 60 nm to maintain the remarkable overall solar cell performance. These results are very promising for future potential applications in thin and high performance CIGS solar cells technology.