Type-I Ca(OH)2/α-MoTe2 vdW heterostructure for ultraviolet optoelectronic device applications: electric field effects

Abstract

The van der Waals (vdW) heterostructure is attracting intensive attention as a unique building block in the construction of future nano-devices. In this work, through first-principle calculations, we systemically predict the stability, electronic structures, band alignment, interface charge transfer and optical absorption of a Ca(OH)₂/α-MoTe₂ vdW heterostructure, considering stacking patterns and electric field (E-field) effects. The studies show that the heterostructure possesses the outstanding characteristics of direct band structures, type-I alignment, high ultraviolet absorption strength (∼10⁵ cm⁻¹) and broadband spectrum. Moreover, the external E-fields can tune the band alignment transformation from type I to type II. These results indicate that the Ca(OH)₂/α-MoTe₂ vdW heterostructure will be a promising candidate for ultraviolet optoelectronic device applications.