Novel two-dimensional CS semiconductor with tunable fantastic electronic and optical properties

Abstract

First-principles calculations are addressed to study the stability, electronic and optical properties of the CS monolayer. It’s found that the CS monolayer has excellent stability and semiconductor characteristics (Indirect band gap of 2.09 eV). Through applying external biaxial strain (-4%∼+4%), the value of the indirect band gap of the CS monolayer is tuned in a wide interval (0.18∼2.86 eV). The electronic and optical properties of the CS monolayer are also regulated by chemical modifications, exhibiting rich changing behaviors. Interestingly, the fully hydrogenated CS monolayer exhibits a wide direct band gap (3.61 eV), while the semi-hydrogenated CS monolayer exhibits an indirect band gap (3.11 eV), both have good stabilities. The absorption spectrum of the CS monolayer is found to have strong absorption in green light (528nm) and ultraviolet light. While those of the chemically modified CS monolayers show strong absorption strength in violet and medium ultraviolet light, showing potential application in ultraviolet devices.