Redirecting focus in CuInSe2 research towards selenium-related defects

Abstract

Density-functional-theory calculations have often been used to interpret experimental observations of defects in CuInSe2 (CIS). In this work, we bring back under scrutiny conclusions drawn from earlier calculations employing the (semi)local-density approximation. We present hybrid-functional results showing that copper- or indium-related defects such as VCu or InCu do not create charge transition levels within the band gap in CIS. Instead, deep levels in CIS can only arise from selenium-related defects, which act as recombination centers in this material.