Comparative Study of Structural and Electronic Properties of Cu-based Multinary Semiconductors

TL;DR

This study systematically compares the structural and electronic properties of Cu-based multinary semiconductors using first-principles calculations, highlighting the importance of Cu d electrons and improving accuracy with advanced functionals.

Contribution

It provides a detailed comparison of computational methods and predicts quasiparticle band gaps for Cu-based semiconductors, aligning well with experimental data.

Findings

HSE06 functional improves anion displacement calculations

Quasiparticle band gaps match experimental values

Predicted band gaps for Cu2ZnSnS4 phases are 1.65 eV and 1.40 eV

Abstract

We present a systematic and comparative study of the structural and electronic properties of Cu-based ternary and quaternary semiconductors using first-principles electronic structure approaches. The important role that Cu d electrons play in determining their properties is illustrated by comparing results calculated with different exchange correlation energy functionals. We show that systematic improvement of the calculated anion displacement can be achieved by using the Heyd-Scuseria-Ernzerhof (HSE06) functional compared with the Perdew-Burke-Ernzerhof (PBE) functional. Quasiparticle band structures are then calculated within the G0W0 approximation using the crystal structures optimized within the HSE06 functional and starting from the PBE+U mean-field solution. Both the calculated quasiparticle band gaps and their systematic variation with chemical constituents agree very well with experiments. We also predict that the quasiparticle band gaps of the prototypical semiconductor Cu2ZnSnS4 in the kesterite (KS) phase is 1.65 eV and that of the stannite (ST) phase is 1.40 eV. These results are also consistent with available experimental values which vary from 1.45 to 1.6 eV.