Light emission, structure-phase evolution, and photocatalytic behavior in full-series multilayered GaTe1−xSx (0 ≤ x ≤ 1) with direct-transition edge

Abstract

The crystal structures and optical properties of full-series multilayered GaTe1−xSx (0 ≤ x ≤ 1) are examined. The results reveal that the monoclinic (M) phase dominates for 0 ≤ x ≤ 0.4, and the hexagonal (H) phase dominates for 0.425 ≤ x ≤ 1. The full-series multilayer GaTe1−xSx exhibited strong photoluminescence. The emission range of M-GaTe1−xSx (0 ≤ x ≤ 0.4) layers displays 1.65–1.77 eV (700–750 nm) and that of the H-GaTe1−xSx (0 ≤ x ≤ 1) layers is 1.588–2.5 eV (496–780 nm). Micro-time-resolved photoluminescence (μTRPL) revealed that the M-phase had a shorter PL recombination lifetime than H-phase because the surface effect. The multilayer GaTe1−xSx (0 ≤ x ≤ 1) exhibited superior light emission and absorption capabilities for application in light-emitting and photocatalytic devices. The GaTe0.5S0.5 nanosheet photocatalyst demonstrated the best photocatalytic performance because its abundant surface state and mixed phases to enhance the photo-degradation ability.

Keywords

• III–VI layer compounds
• 2D semiconductor photocatalyst
• Photoluminescence
• Fluorescence lifetime mapping
• Two-color emitter