Effect of tensile strain on the optoelectronic properties of defective Te systems MoTe2

In this paper, the modulation of the optoelectronic properties of MoTe₂ defective systems by deformation is simulated using first principles. The study documents the bond lengths, defect formation energies, energy band structures, DOS, and various optical properties of the individual systems in both defect states. It is shown that pristine MoTe₂ is a direct band-gap semiconductor material and that both biaxial tensile strain and defect measures reduce the bandgap of the system. When 2 Te atoms are defective, and the tensile strain reaches 6%, the bandgap of the system approaches 0, corresponding to quasi-metallic properties. In terms of optical properties, both biaxial tensile strain and defects reduce the absorption and reflection peaks of the system but increase the reflectivity in the infrared region. Regarding optical properties, the defective system shows an overall decrease in absorption coefficient and reflectance in the tensile strain state, but there is some increase in the low-energy region. These findings may positively impact the flexible application of MoTe₂ in photovoltaics.

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