Electronic structure and optical properties of GaTe/MoTe2 based vdW heterostructure under mechanical strain and external electric fields

In this work, we systematically designed a two-dimensional (2D) heterostructure based on GaTe and MoTe2 monolayers to circumvent the limitations of the constituents and enhance their performance for various optoelectronic and energy applications. All the calculations are performed using Hybrid-Density Functional Theory (DFT) calculations. We observed that the GaTe/MoTe2 heterostructure has an indirect bandgap (Eg) of 1.5 eV with type-I band alignment. Due to the type-I alignment, electrons and holes both reside in the MoTe2 monolayer, which restricts its use in various potential applications. Therefore, the modulation of electronic structure and optical spectra of 2D-GaTe/MoTe2 heterostructure are investigated in detail under external biaxial strain varying from -9% to +9%, and electric field values between +/- 1V/angstrom. We observed, a type II band alignment with high optical visible absorption of order 105 cm-1 within epsilon xy > +2% and Eext between +0.4 V/angstrom to +1 V/angstrom, and -0.6 V/angstrom to -1 V/angstrom. This suggests that the GaTe/MoTe2 heterostructure has excellent potential for various next-generation optoelectronic and energy applications.