Lifetime, quasi-Fermi level splitting and doping concentration of Cu-rich CuInS₂ absorbers

Abstract Cu(In,Ga)S2–based solar cells have been shown by Hiroi et al (Hiroi 2015 IEEE Journal of Photovoltaics 6 309–312) to achieve higher efficiencies with absorbers processed at high deposition temperatures. Additionally, it is known for CuInS 2 that the main improvement from temperatures reduction in density deep defects and increased quasi-Fermi level splitting. The splitting could result a rate recombination or an increase doping concentration. To investigate which effect dominant one, we perform time-resolved photoluminescence measurements estimate concentration carrier lifetime We find no changes effective lifetime, range 200 ps. increases 10 16 cm −3 17 . Our study shows not due non-radiative but