Structural, light emitting, and photoelectrical properties of multilayered 2D mixed alloys of gallium monochalcogenides

Gallium monochalcogenides (GaX, where X represents Te, Se, or S) have attracted significant attention in the development of 2D semiconductor materials owing to their specific optical and electrical characteristics. Multilayered mixed GaX compounds, ternary alloys of gallium chalcogenides, are mostly direct semiconductors and are considered excellent candidates for wide energy-range light-emitting materials for application in future optoelectronic devices. This review provides a thorough investigation into ternary alloys of gallium monochalcogenides, focusing on the GaTe1−xSex, GaSe1−xSx, and GaTe1−xSx series of layered semiconductor compounds. We provide a comprehensive overview of the methods used to grow these materials, analyze their crystal structures, and characterize their properties. Various growth methods and conditions and their material yields are described. Structural characterization methods reveal detailed information on the composition-driven variations in crystal structure and phase. An optical property analysis reveals the remarkable tunability of their bandgaps and emission spectra, establishing their potential for optoelectronics applications. The light emission range of the GaTe1−xSex series is from near-infrared (NIR) to visible (620–780 nm), while the GaSe1−xSx series emits from the visible to the blue region (478–620 nm) achieving white light. The GaTe1−xSx exhibits the most extensive emission range, spanning from NIR to the blue region (478–780 nm). Furthermore, GaTe1−xSx exhibit high photocatalytic degradation activity for water splitting and organic pollutant degradation. Overall, this review highlights the promising prospects of ternary gallium chalcogenides for advancing future optoelectronics technologies.