Novel Two-Dimensional Layered MoSi(2)Z(4) (Z = P, As): New Promising Optoelectronic Materials

Very recently, two new two-dimensional (2D) layered semi-conducting materials MoSi [Formula: see text] N [Formula: see text] and WSi [Formula: see text] N [Formula: see text] were successfully synthesized in experiments, and a large family of these two 2D materials, namely MA [Formula: see text] Z [Formula: see text] , was also predicted theoretically (Science, 369, 670 (2020)). Motivated by this exciting family, in this work, we systematically investigate the mechanical, electronic and optical properties of monolayer and bilayer MoSi [Formula: see text] P [Formula: see text] and MoSi [Formula: see text] As [Formula: see text] by using the first-principles calculation method. Numerical results indicate that both monolayer and bilayer MoSi [Formula: see text] Z [Formula: see text] (Z = P, As) present good structural stability, isotropic mechanical parameters, moderate bandgap, favorable carrier mobilities, remarkable optical absorption, superior photon responsivity and external quantum efficiency. Especially, due to the wave-functions of band edges dominated by d orbital of the middle-layer Mo atoms are screened effectively, the bandgap and optical absorption hardly depend on the number of layers, providing an added convenience in the experimental fabrication of few-layer MoSi [Formula: see text] Z [Formula: see text]-based electronic and optoelectronic devices. We also build a monolayer MoSi [Formula: see text] Z [Formula: see text]-based 2D optoelectronic device, and quantitatively evaluate the photocurrent as a function of energy and polarization angle of the incident light. Our investigation verifies the excellent performance of a few-layer MoSi [Formula: see text] Z [Formula: see text] and expands their potential application in nanoscale electronic and optoelectronic devices.