Stability and Electronic Structures of Group IV Semiconductor Alloy Nanosheets: a First Principles Study

Abstract

The structural stability and electronic properties of graphene-like alloy nanosheets composed of group IV elements, such as monolayer Si x Ge1− x , Ge x Sn1− x , and Si x Sn1− x , are systematically investigated by means of density functional calculations. Our calculations demonstrate that the buckled configuration is stabilized over the entire composition range. The analysis of band structures reveals that a linear band dispersion with Dirac cone at the K point similar to graphene appears in Si x Ge1− x , whereas a small energy gap within 0.23 eV is formed at the K point in Si x Sn1− x and Ge x Sn1− x for 0.375 ≤ x ≤ 0.625. These results suggest that composition control is of importance in tailoring the electronic properties of group IV alloy nanosheets.