Electrical, optical and mechanical properties of monolayer MoTe₂ for applications in wearable optoelectronic devices

Abstract

Transition metal dichalcogenides (TMDs) have excellent optical and mechanical properties and has potential application value in wearable optoelectronic response devices. In this paper, MoTe2, a representative material of TMDs, is studied by first principles calculation. The results show that the MoTe2 monolayer has a direct band gap of 1.10eV in the eigenstate, which has a strong light absorption capacity, and can produce a high concentration of photogenerated charge carriers after light absorption. The material is soft in texture and exhibits the unique mechanical properties of layered materials. The effects of biaxial strain and defects on the properties of the materials were analyzed. The results show that the biaxial compression strain can enhance the light absorption curve of the material, enhance the light absorption of the photogenerated carrier, and expand the range of its energy distribution. The tensile strain decreases the value of the photoabsorbance curve and decreases the range of energy distribution of photogenerated carriers. The Mo vacancy defect increases the absorption curve value in the low energy region and broadens the optical response range of the material. The two types of vacancy defects both induce a "discrete" distribution of photogenerated carriers. The Mo vacancy has a significant effect on the elastic modulus and anisotropy properties of the material, resulting in the material changing from ductile to brittle. When Mo vacancy is added, the spatial distribution of elastic modulus of the material also changes greatly. Therefore, MoTe2 has potential application in the field of flexible optoelectronic devices, and its performance can be controlled by stress, vacancy.