Strain-Tunable Electronic Properties and Band Alignments in GaTe/CN Heterostructure: a First-Principles Calculation.

Recently, GaTe and CN monolayers have been successfully synthesized and show fascinating electronic and optical properties. Such hybrid of GaTe with CN may induce new novel physical properties. In this work, we perform ab initio simulations on the structural, electronic, and optical properties of the GaTe/CN van der Waals (vdW) heterostructure. Our calculations show that the GaTe/CN vdW heterostructure is an indirect-gap semiconductor with type-II band alignment, facilitating an effective separation of photogenerated carriers. Intriguingly, it also presents enhanced visible-UV light absorption compared to its components and can be tailored to be a good photocatalyst for water splitting at certain pH by applying vertical strains. Further, we explore specifically the adsorption and decomposition of water molecules on the surface of CN layer in the heterostructure and the subsequent formation of hydrogen, which reveals the mechanism of photocatalytic hydrogen production on the 2D GaTe/CN heterostructure. Moreover, it is found that in-plane biaxial strains can induce indirect-direct-indirect, semiconductor-metal, and type II to type I or type III transitions. These interesting results make the GaTe/CN vdW heterostructure a promising candidate for applications in next generation of multifunctional optoelectronic devices.