Band alignment engineering, electronic and optical properties of Sb/PtTe2 van der Waals heterostructure: effects of electric field and biaxial strain

Abstract

We investigated structural, electronic, and optical properties of Sb/PtTe2 van der Waals heterostructure using density functional theory. Four different configurations were chosen to investigate the band structures and find the most stable configuration. Due to the distance between two individual layers (3.59 A) and calculations of vdW-corrections the interface interactions of Sb/PtTe2 are controlled by vdW forces. Our wannierized band structure calculations along with the band alignment of the most stable configuration show that the nature of valence band maximum and conduction band minimum are contributed by PtTe2 resulting a type I band alignment with an indirect bandgap (1.05 eV), making efficient recombination of the photogenerated electron-holes due to confining electrons irradiated by light. Moreover, using an external vertical electric field we showed that the nature of the band alignment could be affected by changing to a type-II band alignment by increasing the electric field to 2 (V/A). We also investigated the effect of biaxial strain on the structural and electronic properties of the heterostructure. The band alignment and energy bandgap could be modified in this way. Also, the present study shows strong enhanced optical absorption from infrared to UV regions. Our results indicate that Sb/PtTe2 could be a promising new material in nanoscale electronic and optoelectronic devices.