Study of heterostructures of Cu_3BiS_3-buffer layer measured by Kelvin probe force microscopy measurements (KPFM)

摘要

The interface formed between Cu_3BiS_3 thin films and the buffer layer is a potentially limiting factor to the performance of solar cells based on Al/Cu_3BiS_3/buffer heterojunctions. The buffer layers of ZnS and In_2S_3 were grown by co-evaporation, and tested as an alternative to the traditional CdS deposited by chemical bath deposition. From the Kelvin probe force microscopy measurements, we found the values of the work function of ZnS, In_2S_3, and CdS, layers deposited into Cu_3BiS_3. Additionally, different electronic activity was found for different grain boundaries (GBs), from studies under illumination, we also found the net doping concentration and the density of charged GB states for Cu_3BiS_3 and Cu_3BiS_3/CdS.