Stable Monolayer alpha-Phase of CdTe: Strain-Dependent Properties

TL;DR

This paper introduces a stable, monolayer alpha-phase of CdTe with tunable direct band gap suitable for optoelectronic applications, demonstrated through first-principles calculations showing its stability and strain-dependent electronic properties.

Contribution

It presents the first theoretical investigation of a monolayer alpha-phase of CdTe, revealing its stability, electronic structure, and strain-tunable properties for optoelectronic uses.

Findings

Monolayer alpha-CdTe is dynamically stable and mechanically flexible.

It has a direct band gap of 1.95 eV in the visible spectrum.

The band gap can be tuned by biaxial strain.

Abstract

CdTe is a well known and widely used binary compound for optoelectronic applications. In this study, we propose the thinnest, free standing monolayer of CdTe which holds the tetragonal-PbO (alpha-PbO) symmetry. The structural, electronic, vibrational and strain dependent properties are investigated by means of first principles calculations based on density functional theory. Our results demonstrate that the monolayer alpha-CdTe is a dynamically stable and mechanically flexible material. It is found that the thinnest monolayer crystal of CdTe is a semiconductor with a direct band gap of 1.95 eV, which corresponds to red light in the visible spectrum. Moreover, it is found that the band gap can be tunable under biaxial strain. With its strain-controllable direct band gap within the visible spectrum, stable alpha-phase of monolayer CdTe is a suitable candidate for optoelectronic device applications.