Electronic Properties of Graphene-ZnO Interface: A Density Functional Theory Investigation

Our study provides significant new results for an important interface in current and future nanoelectronics, namely the Graphene-ZnO interface. The manuscript includes the results of intensive density functional calculations for the interface between several ZnO surfaces and a single layer graphene. The structural properties and the binding energies at the interface are calculated for three different ZnO surfaces. The Zn-terminated (0001) and O-terminated (000-1) surfaces as well as nonpolar (10-10) surface are considered in the present study. We also investigate the electronic properties of the contact by calculating the interfacial potential barrier based on projected density of states at different layers. The results indicate the crucial role of interfacial oxygen density on the electronic behavior of the contact, which in turn can be employed to explain experimental discrepancies on the Ohmic or Schottky behavior of this interface. Calculations for interfaces with oxygen vacancies support our finding and explain experimental results for thermally treated samples.