Density Functional Theory Study of Layer-Controlled Band Gap and Strong Anisotropic Properties in ScSI Nanosheet: Implications for Photoelectric Sensor

Moderateband gap and high stabilities are key propertiesin (opto)electronicdevices application. Based on first-principles calculations, we predictedan ultrathin two-dimensional (2D) semiconductor, namely, a ScSI nanosheet,with tunable electronic properties and high stabilities. The ScSImonolayer is an indirect semiconductor with a band gap of 2.59 eV,and significantly, this monolayer can shift from an indirect to directband gap under small strains. Moreover, the cleavage energy of theScSI monolayer is lower than that of graphene, and this monolayerpossesses high dynamical, thermal, and mechanical stabilities, suggestingthe possibility of mechanical exfoliation experimentally. Interestingly,due to the quantum confinement effect, the band gaps of the ScSI nanosheetsexhibit a layer-dependent exponential decay relationship with an increasing number of layers. The exceptional properties render ScSI nanosheetsa promising candidate for flexible applications in optoelectronicdevices especially in photoelectric sensors.

Automated summary

We predicted an ultrathin two-dimensional (2D) semiconductor, ScSI nanosheet, with tunable electronic properties and high stabilities based on first-principles calculations. The ScSI monolayer is an indirect semiconductor with a band gap of 2.59 eV, which can shift from an indirect to direct band gap under small strains. Moreover, the ScSI monolayer possesses high dynamical, thermal, and mechanical stabilities, and its band gaps exhibit a layer-dependent exponential decay relationship.