Native point defects in few-layer phosphorene

TL;DR

This study uses advanced computational methods to analyze native point defects in few-layer phosphorene, revealing their stability, electronic properties, and role in p-type conductivity, with implications for electronic applications.

Contribution

It provides detailed insights into the stability and electronic effects of native defects in few-layer phosphorene using hybrid DFT calculations.

Findings

Vacancies and interstitials are more stable in outer layers.

Defect formation energies decrease with increasing layer thickness.

Defects can act as shallow acceptors and electron compensating centers.

Abstract

Using hybrid density functional theory combined with a semiempirical van der Waals dispersion correction, we have investigated the structural and electronic properties of vacancies and self-interstitials in defective few-layer phosphorene. We find that both a vacancy and a self-interstitial defect are more stable in the outer layer than in the inner layer. The formation energy and transition energy of both a vacancy and a self-interstitial P defect decrease with increasing film thickness, mainly due to the upward shift of the host valence band maximum in reference to the vacuum level. Consequently, both vacancies and self-interstitials could act as shallow acceptors, and this well explains the experimentally observed p-type conductivity in few-layer phosphorene. On the other hand, since these native point defects have moderate formation energies and are stable in negatively charged states, they could also serve as electron compensating centers in n-type few-layer phosphorene.