Electronic and optical structure of wurtzite CuInS2

We present a theoretical study of the electronic structure ofthe wurtzite CuInS2 material. To address reliably some material properties ofthis new phase we use hybrid density functional theory. Among possiblewurtzite polymorphs, we have determined the most stable phase on the basisof total energy minimization. The minimum energy structure exhibits asemiconducting ground state with a band gap of ∼1.3 eV in excellentagreement with experimental data. We use time-dependent densityfunctional theory to compare the optical response of the chalcopyrite andwurtzite phases and to identify the nature of the optically active transitions inthe vicinity of the absorption edge. Our analysis indicates that the wurtzite CuInS2 structure is a suitable material for photovoltaicapplications