Computational insights into structural, electronic and optical characteristics of GeC/CN van der Waals heterostructures: effects of strain engineering and electric field.

Vertical heterostructures from two or more than two two-dimensional materials are recently considered as an effective tool for tuning the electronic properties of materials and for designing future high-performance nanodevices. Here, using first principles calculations, we propose a GeC/CN van der Waals heterostructure and investigate its electronic and optical properties. We demonstrate that the intrinsic electronic properties of both GeC and CN monolayers are quite preserved in GeC/CN HTS owing to the weak forces. At the equilibrium configuration, GeC/CN HTS forms the type-II band alignment with an indirect band gap of 0.42 eV, which can be considered to improve the effective separation of electrons and holes. Besides, GeC/CN vdW-HTS exhibits strong absorption in both visible and near ultra-violet regions with an intensity of 10 cm. The electronic properties of GeC/CN HTS can be tuned by applying an electric field and vertical strains. The semiconductor to metal transition can be achieved in GeC/CN HTS in the case when the positive electric field of +0.3 V Å or the tensile vertical strain of -0.9 Å is applied. These findings demonstrate that GeC/CN HTS can be used to design future high-performance multifunctional devices.