Effects of sulfur substitution in amorphous InGaZnO4: optical properties and first-principles calculations

Abstract

Amorphous InGaZnO4-xSx thin films were fabricated using a polycrystalline InGaZnO4 target by pulsed laser deposition in an H2S gas flow. The optical band gap first decreased from 3.05 to 1.65 eV as x increased from 0 to 1.5, and then increased to 2.6 eV at larger x, showing a bandgap bowing behavior. All the sulfur-containing films have high resistance beyond our measurement limit. Film density of the a-InGaZnS4 film was decreased by similar to 40% from that of a-InGaZnO4. Density functional theory calculations were performed to explain these results. (C) 2015 The Ceramic Society of Japan. All rights reserved.