DFT exploration of p-type conductivity and fully visible light transparency in chalcopyrite AgMCh2 (M=Al, Ga; Ch=S, Se, Te)

Abstract

Transparent conducting materials (TCMs) are essential in the modern optoelectronic field. Currently, the commercially and extensively used TCMs are dominated by n-type candidates, while the high-performance p-type counterparts are rare. Through theoretical calculations, we find that among the chalcopyrite AgMCh2 series (M=Al, Ga; Ch=S, Se, Te), only AgAlS2 meet the ductile, visible-light transparent, and p-type electrical candidate requirements. When samples' thickness reaches 100.0 nm, AgAlS2 preserves the high visible light transmittance (above 80.0% along x(y)-direction). Defect analysis confirms the p-type electrical conductivity is dominated by intrinsic defect Ag vacancy (VAg). As an exceptional p-type electrical conducting candidate, the hole mobility can reach 20.7 cm2/V·s, and its p-type electrical conductivity (room temperature) attains 103 S/m with hole density of 1019 cm-3. Considering the limitations of equilibrium preparation scheme, the nonequilibrium preparation strategies are essential to fabricate the intrinsic defects in AgAlS2. This work provides a key insight into the properties and expands the applications of AgAlS2, and pave new way for design and exploration of the fully visual light transparent and p-type electrical conducting systems.