Sulfur vacancy activated field effect transistors based on ReS2 nanosheets

Abstract

Rhenium disulphide (ReS₂) is a recently discovered new member of the transition metal dichalcogenides. Most impressively, it exhibits a direct bandgap from bulk to monolayer. However, the growth of ReS₂ nanosheets (NSs) still remains a challenge and in turn their applications are unexplored. In this study, we successfully synthesized high-quality ReS₂ NSs via chemical vapor deposition. A high-performance field effect transistor of ReS₂ NSs with an on/off ratio of ∼10⁵ was demonstrated. Through both electrical transport measurements at varying temperatures (80 K–360 K) and first-principles calculations, we find sulfur vacancies, which exist intrinsically in ReS₂ NSs and significantly affect the performance of the ReS₂ FET device. Furthermore, we demonstrated that sulfur vacancies can efficiently adsorb and recognize oxidizing (O₂) and reducing (NH₃) gases, which electronically interact with ReS₂ only at defect sites. Our findings provide experimental groundwork for the synthesis of new transition metal dichalocogenides, supply guidelines for understanding the physical nature of ReS₂ FETs, and offer a new route toward tailoring their electrical properties by defect engineering in the future.