Anisotropic Spectroscopy and Electrical Properties of 2D ReS_2(1–<i>_x</i>₎Se₂<i>_x</i> Alloys with Distorted 1T Structure

Abstract

2D black phosphorus (BP) and rhenium dichalcogenides (ReX₂ , X = S, Se) possess intrinsic in-plane anisotropic physical properties arising from their low crystal lattice symmetry, which has inspired their novel applications in electronics, photonics, and optoelectronics. Different from BP with poor environmental stability, ReX₂ has low-symmetry distorted 1T structures with excellent stability. In ReX₂ , the electronic structure is weakly dependent on layer numbers, which restricts their property tunability and device applications. Here, the properties are tuned, such as optical bandgap, Raman anisotropy, and electrical transport, by alloying 2D ReS₂ and ReSe₂ . Photoluminescence emission energy of ReS_2(1-_x₎ Se₂_x monolayers (x from 0 to 1 with a step of 0.1) can be continuously tuned ranging from 1.62 to 1.31 eV. Polarization behavior of Raman modes, such as ReS₂ -like peak at 212 cm^-1 , shifts as the composition changes. Anisotropic electrical property is maintained in ReS_2(1-_x₎ Se₂_x with high electron mobility along b-axis for all compositions of ReS_2(1-_x₎ Se₂_x .