Strain-Tunable Electronic Properties and Band Alignments in GaTe/C 2 N Heterostructure: a First-Principles Calculation.

Recently, GaTe and C ₂ N monolayers have been successfully synthesized and show fascinating electronic and optical properties. Such hybrid of GaTe with C ₂ N may induce new novel physical properties. In this work, we perform ab initio simulations on the structural, electronic, and optical properties of the GaTe/C ₂ N van der Waals (vdW) heterostructure. Our calculations show that the GaTe/C ₂ N 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 C ₂ N layer in the heterostructure and the subsequent formation of hydrogen, which reveals the mechanism of photocatalytic hydrogen production on the 2D GaTe/C ₂ N 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/C ₂ N vdW heterostructure a promising candidate for applications in next generation of multifunctional optoelectronic devices.