Vacancies and dopants in two-dimensional tin monoxide: An ab initio study

TL;DR

This study uses first-principles simulations to explore oxygen vacancies and dopants in 2D tin monoxide, revealing defect dynamics and doping strategies for electronic and photocatalytic applications.

Contribution

It provides new insights into defect behavior and doping effects in monolayer SnO, highlighting the potential for defect engineering in 2D SnO-based devices.

Findings

O vacancies are the dominant native defect under Sn-rich conditions.

F dopants can lead to high stability and degenerately doped phases.

Doping can induce n/p-type behavior and metallization.

Abstract

Layered tin monoxide (SnO) offers an exciting two-dimensional (2D) semiconducting system with great technological potential for next-generation electronics and photocatalytic applications. Using a combination of first-principles simulations and strain field analysis, this study investigates the structural dynamics of oxygen (O) vacancies in monolayer SnO and their functionalization by complementary lightweight dopants, namely C, Si, N, P, S, F, Cl, H and H$_{2}$. Our results show that O vacancies are the dominant native defect under Sn-rich growth conditions with active diffusion characteristics that are comparable to that of graphene vacancies. Depending on the choice of substitutional species and its concentration within the material, significant opportunities are revealed in the doped-SnO system for facilitating $n$/$p$-type tendencies, work function reduction, and metallization of the monolayer. N and F dopants are found to demonstrate superior mechanical compatibility with the host lattice, with F being especially likely to take part in substitution and lead to degenerately doped phases with high open-air stability. The findings reported here suggest that post-growth filling of O vacancies in Sn-rich conditions presents a viable channel for doping 2D tin monoxide, opening up new avenues in harnessing defect-engineered SnO nanostructures for emergent technologies.