Intrinsic defects in CdSeTe and their impact on group-V doping

This work evaluates the intrinsic defect properties of CdSeXTe(1-X) (CST) absorbers through evaluation of optoelectronic properties of various CST devices. By comparing devices with extrinsic p-type doping (As or P) to those with extrinsic n-type doping (Al or In), in addition to non-intentionally doped CST, we aim to understand the roles played by impurities in CdTe (dopants, Se, and Cl). We find that CST films are intrinsically n-type, as confirmed by Kelvin Probe Force Microscopy (KPFM) and reinforced with quantum efficiency (QE) measurements under different excitation incidences. The concentration and distribution of Se through CST has the most significant impact on formation of donor defects and subsequent device performance. This reinforces the importance of tailoring the Se profile and its potential role in compensating group-V dopants.