Device modeling and simulation of CIS-based solar cells

A comprehensive device modeling and numerical simulation of the performance of Cu(In,Ga)Se/sub 2/ (CIGS) solar cells with an emphasis on band-gap engineering of the CIGS absorber layers has been carried out using the AMPS-1D device simulation program. A variety of graded band-gap structures including back surface grading and double grading of the CIGS absorber layers are examined. The device physics and performance parameters of the absorber layer structures with different band-gap profiles are analyzed. Based on the simulation results, an optimal graded band-gap structure for the CIGS cell is proposed. Additionally, the dependence of performance parameters for the CIGS cells on the existence, carrier mobility, carrier density, and thickness of the Cu-poor surface defect layer on the CIGS absorber layers are also investigated.