2D Rhenium Dichalcogenides: From Fundamental Properties to Recent Advances in Photodetector Technology

Van der Waals (vdW) materials of transition metal dichalcogenides (TMD) family with semiconducting properties are currently at the forefront of research in the field of optoelectronics. The ability to couple them with one another at atomic interface precision in a synergistic way opens up unprecedented opportunities to design photodetectors of broad spectral range with excellent figures of merits not accessible to discrete materials. Recent years have seen a surge of interest in group VII TMD materials (ReS₂ and ReSe₂) due to their strong optical response from bulk to monolayer and good ambient stability. Their band gap energies spanning over visible and near-infrared ranges and the strong linear polarization sensitivity stemming from the distorted octahedral symmetry, are ideally suited for polarization-sensitive photodetectors. This review aims at providing a comprehensive understanding of the fundamental properties, optical identification of various structural features, long-debated question of band gap nature and interlayer coupling, and recent advances in the development of photodetectors based on ReS₂, ReSe₂, and their vdW heterostructures with other layered materials of practical importance. We critically review various conceptual device designs implemented based on band engineering, emphasize on the merits of these photodetectors and their potential applications, and provide an outlook for future prospects.