Composition‐tunable SnSe_(1−x)S_x (0 ≤ x ≤ 1) single crystals toward efficient bandgap engineering and optical/thermal properties

Abstract

Bulk tin‐based monochalcogenides are composed of earth‐abundant, low‐cost, and non‐toxic chemical elements, which possess high thermoelectric properties making them candidate for waste heat recovery applications. Bandgap engineering offers opportunity to customize the characteristics of semiconductors as desired applications in microelectronic, thermoelectric, and so on. The bandgap of tin‐based monochalcogenides is systematically regulated by the solid‐solution method. The thermal and optical properties of SnSe(1–x)Sx (0 ≤ x ≤ 1) single crystals, synthesized successfully by a home‐modified Bridgman method, have been systematically investigated. A variety of characterizations, including x‐ray diffraction, electron microscopy, Raman spectroscopy, absorbance spectroscopy, and thermal analyzer, are employed to confirm the precise tuning of the component. As the S compositions increased from 0 to 1, the unit cell parameter, interplanar spacing, and optical phonon frequency exhibited a linear change, aligning with the expected bandgap shifts and calculated results. Our work will promote the advancement of the SnSe and SnS materials in areas including thermoelectricity and photovoltaics.