Two-Dimensional Octuple-Atomic-Layer M(2)Si(2)N(4) (M = Al, Ga and In) with Long Carrier Lifetime

Bulk III-nitride materials MN (M = Al, Ga and In) and their alloys have been widely used in high-power electronic and optoelectronic devices, but stable two-dimensional (2D) III-nitride materials, except h-BN, have not been realized yet. A new kind of 2D III-nitride material M [Formula: see text] Si [Formula: see text] N [Formula: see text] (M = Al, Ga and In) is predicted by choosing Si as the appropriate passivation element. The stability, electronic and optical properties of 2D M [Formula: see text] Si [Formula: see text] N [Formula: see text] materials are studied systematically based on first-principles calculations. The results show that Al [Formula: see text] Si [Formula: see text] N [Formula: see text] and Ga [Formula: see text] Si [Formula: see text] N [Formula: see text] are found to be indirect bandgap semiconductors, while In [Formula: see text] Si [Formula: see text] N [Formula: see text] is a direct bandgap semiconductor. Moreover, Al [Formula: see text] Si [Formula: see text] N [Formula: see text] and In [Formula: see text] Si [Formula: see text] N [Formula: see text] have good absorption ability in the visible light region, while Ga [Formula: see text] Si [Formula: see text] N [Formula: see text] is an ultraviolet-light-absorbing material. Furthermore, the carrier lifetimes of Ga [Formula: see text] Si [Formula: see text] N [Formula: see text] and In [Formula: see text] Si [Formula: see text] N [Formula: see text] are as large as 157.89 and 103.99 ns, respectively. All these desirable properties of M [Formula: see text] Si [Formula: see text] N [Formula: see text] materials make them attractive for applications in electronics and photoelectronics.