Design of an Interfacial Layer to Block Chemical Reaction for Epitaxial ZnO Growth on a Si Substrate

Epitaxial growth of ZnO film on Si(111) substrates using an MgO interfacial layer has been investigated. The MgO layer acts as a thermodynamically stable buffer layer to suppress interfacial reaction between ZnO and Si, producing a clear interface. A domain-matched structure with mixed 4/3 and 5/4 domains was formed at the interface of Si and MgO to achieve the lowest domain mismatch. Moreover, the epitaxial ZnO film was grown on a MgO buffer layer with a domain matched structure of 11/12 domains, resulting in an (0001)[12̅10] ZnO ∥(111)[11̅0] MgO ∥(111)[11̅0] Si epitaxial relation. The high crystallinity of ZnO film grown on MgO/Si shows good optical performance with strong photoluminescence and improved Hall mobility.