Tailoring the optoelectronic properties of g-C6N6/GaTe vdW heterojunction by biaxial strain

Abstract

Water splitting, a green route to convert solar energy into chemical energy, is regarded as a promising strategy to settle the continuous growth of the energy crisis and environmental pollution. In this work, the theoretical study of the optoelectronic and photocatalytic properties of novel g-C6N6/GaTe heterojunction is solved by the first-principles calculations in detail. It is found that the heterojunction is an indirect band gap semiconductor of 1.48 eV using HSE06 methods. The heterojunction exhibits a type-II band structure, which results in the effective separation of the photogenerated charge carriers. In addition, the g-C6N6/GaTe heterojunction has suitable band edge positions for redox reactions and excellent optical characteristics in the visible-light region. By applying different biaxial strains, the optoelectronic properties of the heterojunction can be effectively adjusted in a wide range of −3 %–5 %. A biaxial strain with a strength of 4 % can induce forming of the type-I band alignment in the g-C6N6/GaTe heterojunction. An excellent feature is found that the electronic properties of the heterojunction keep quite steady in a wide strain range of −1 % to 4 %, and the heterojunction can be suitable for overall water splitting even under the strain of −2 %–4 %. Our findings may provide the theoretical guide for the potential application of g-C6N6/GaTe heterojunction in photocatalyst and optoelectronic devices.