Designing isoelectronic counterparts to layered group V semiconductors

TL;DR

This paper proposes IV-VI compounds as isoelectronic counterparts to layered group V semiconductors, studying silicon mono-sulfide's structural phases and electronic properties using ab initio calculations.

Contribution

It introduces new structural phases of SiS and explores their stability, polarization, and heterostructure formation with phosphorene, expanding the understanding of 2D semiconductor materials.

Findings

α- and β-SiS are nearly equally stable

Both SiS monolayers have a strain-dependent indirect band gap

SiS can form heterostructures with phosphorene with low energy penalty

Abstract

In analogy to III-V compounds, which have significantly broadened the scope of group IV semiconductors, we propose IV-VI compounds as isoelectronic counterparts to layered group V semiconductors. Using {\em ab initio} density functional theory, we study yet unrealized structural phases of silicon mono-sulfide (SiS). We find the black-phosphorus-like $\alpha$-SiS to be almost equally stable as the blue-phosphorus-like $\beta$-SiS. Both $\alpha$-SiS and $\beta$-SiS monolayers display a significant, indirect band gap that depends sensitively on the in-layer strain. Unlike 2D semiconductors of group V elements with the corresponding nonplanar structure, different SiS allotropes show a strong polarization either within or normal to the layers. We find that SiS may form both lateral and vertical heterostructures with phosphorene at a very small energy penalty, offering an unprecedented tunability in structural and electronic properties of SiS-P compounds.