Stable monolayer α-phase of CdTe: strain-dependent properties

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 tetragonalPbO (α-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 α-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 α-phase of monolayer CdTe is a suitable candidate for optoelectronic device applications.

Polymorphism of CdTe in the Few‐Monolayer Limit

“…In the latter case, the unstable bulk (wurtzite) phase possessed strong imaginary modes. [7] After submission of this work, our attention was brought to work by Unsal et al, [23] where a stable α-phase of CdTe was reported (Figure 6). It is interesting to note an important similarity between them, namely, the Cd atomic planes are sandwiched between Te atomic planes.…”

“…Figure 6. The fully relaxed structure of monolayer α-CdTe [23] shown in different projections. The lower-right panel shown an axonometric image of the structure.…”

Bonding Heterogeneity Inducing Low Lattice Thermal Conductivity and High Thermoelectric Performance in 2D CdTe2

“…In 2017, researchers predicted a α-CdTe (tetragonal-PbO structure) monolayer with low formation enthalpy and excellent dynamic stability. The novel electronic structure endows 2D α-CdTe with a promising application potential in optoelectronic devices . In 2020, Naseri et al built a planar 2D CdTe, with the use of the predicted CdS honeycomb structure .…”

A first-principles study of electronic and optical properties of the tetragonal phase of monolayer ZnS modulated by biaxial strain

“…18 In addition, strain modulation and element doping in the 2D ZnS have also been carried out. 15,19,20 Recently, a tetragonal phase has been reported in monolayer CdTe, 21 CdSe, 22 CdS 22 and ZnSe; 23 as one of these II–VI compounds, monolayer ZnS also possesses a similar structure. 24 However, the knowledge of monolayer tetragonal ZnS remains very limited, 25 which severely impedes its practical application.…”