Graphene/Janus ZnO heterostructure to build highly efficient photovoltaic properties

We investigated the effect of F and Cl functionalization of Janus ZnO on the optoelectronic propertiesof Graphene/ZnO (Gra/ZnO) heterojunctions by using Density Functional Theory (DFT). The calculated results show that the Janus ZnO/Gra heterojunction is a van der Waals heterojunction with layer spacing >3 Å for both stacking styles. In addition, the functionalized heterojunction retains the original structure of Gra and has an interface formation energy of <0, making it easy to prepare chemically. Furthermore, different stacking styles can convert heterojunctions from n-type Schottky to ohmic contacts, which has promising applications in field-effect transistors. Moreover, functionalized Janus ZnO/Gra can effectively enhance interlayer charge transfer and improve the transmittance of the heterojunction, which is beneficial for applications in nanoelectronic devices.