LAUSR

Abstract Since the discovery of graphene, two-dimensional (2D) layered nanomaterials have been receiving continuous attention owing to their extraordinary properties and promising applications in nanoelectronics. However, many 2D nanomaterials are gapless or possess a small band-gap (≤2 eV), which greatly restricts their applications. Here, by means of ab initio calculations and molecular dynamics simulcations, we report a class of emerging 2D semiconductors, mono- and few-layer arsenic trichalcogenides (As2S3 and As2Se3), with a broad band-gap range from 2.06 eV to 3.18 eV, which can be manipulated by the number of layers or external strains. Interestingly, under moderate tensile strain, the nanolayers undergo a transition from indirect to direct band-gap semiconductors. More importantly, these 2D semiconductors exhibit suitable band-edge alignment and desirable optical absorption, suggesting their potential applications for photocatalysis and optoelectronics. Thanks to the small exfoliation energies, these 2D layered materials could be fabricated from experiments feasibly and serve as promising candidates in constructing van der Waals heterostructures for future nanoelectronics.