Effects Of The Cigs/Buffer Region On Device Performance

Device simulation is employed to investigate how the electronic properties of the Cu-poor region at the CIGS/buffer interface affect the performance of CIGS devices. Features including the thickness, band gap, band off-sets, doping, and defect concentration are considered. Single versus double band gap grading of the absorber is also studied. Although, practically, the Cu-poor region reduces interface defects and shunting, its direct electronic properties do not serve to improve efficiency. Strategies that avoid Cu-poor fabrication while still realizing its secondary benefits may be warranted. Power conversion efficiency could also be improved by using an optimized single graded CIGS band gap.