First-principles design of g-C3N4/HfSSe heterojunctions for optoelectronic applications

Based on first-principles calculations, the structure, electronic and optical properties of g-C₃N₄/HfSSe heterojunctions have been systematically explored. We prove the stability of two heterojunctions by comparing the binding energies from six different stacking heterojunctions, which name are g-C₃N₄/SHfSe heterojunction and g-C₃N₄/SeHfS heterojunction, respectively. It is shown that both heterojunctions behave direct band gaps with type II band alignment. The charge is rearranged at the interface after the heterojunctions are formed, which results in the formation of the built-in electric field. In the ultraviolet, visible and near-infrared regions, excellent light absorption is found in g-C₃N₄/HfSSe heterojunctions.