Piezoelectricity in Two-Dimensional Group III Monochalcogenides

TL;DR

This paper demonstrates that certain group-III monochalcogenides in monolayer form exhibit significant piezoelectricity, expanding the family of 2D piezoelectric materials and enabling integrated electromechanical and optical sensing applications.

Contribution

It reveals that GaS, GaSe, and InSe monolayers are piezoelectric, with coefficients comparable to known 2D piezoelectrics, broadening material options for nanoelectromechanical systems.

Findings

GaS, GaSe, and InSe monolayers are piezoelectric.

Piezoelectric coefficients are comparable to BN and MoS2 monolayers.

Potential for integrated electromechanical and optical sensors.

Abstract

We find that several layer-phase group-III monochalcogenides, including GaS, GaSe and InSe, are piezoelectric in the monolayer form. First-principles calculations reveal that the piezoelectric coefficients of monolayer GaS, GaSe and InSe are on the same order of magnitude as the earlier discovered two-dimensional piezoelectric materials, such as BN and MoS2 monolayers. Our study expands the family of two dimensional piezoelectric materials, suggesting that strong piezoelectric response can occur in a wide range of two dimensional materials with broken inversion symmetry. The co-existence of piezoelectricity and superior photo-sensitivity in these two-dimensional semiconductors enables the integration of electromechanical and optical sensors on the same material platform.