Interfacial Structures Of Inclined ZnO Film On The MgO(011) Substrate

With increasing development of the big data and artificial intelligence,pursuing smaller size,faster response and lower consumption in the application of modern electronics attracts intense interests.Combining different phase structure materials with unique properties to design the novel devices plays a significant role in the development of modern electronics.ZnO as a typical opt-semiconductor with a stable hexagonal phase is always attracted numerous attentions due to its unique optoelectronic properties,such as wider band-gap(~3.4 eV),higher bond exciton energy(~60meV)and larger piezoelectric coefficients.However,ZnO films emerge extremely complex growth behaviors and interface structures because of large mismatch and phase structure asymmetry in these type of combinations,such as growth orientation transformations and c-axis inclined growths.Thus,it is a big challenge to precisely control these film growths.Here,we fabricate a typically large mismatch film based on the coupling between hexagonal ZnO film and cubic MgO substrate to mainly investigate the characteristics of this complex interfaces.The ZnO film was prepared by the molecular beam epitaxy method on the MgO(011)substrate.The analysis results from its in situ reflection high energy electron diffraction(RHEED)patterns,X-ray diffraction(XRD)-pole figures and transmission electron microscopy(TEM)images demonstrate that the film appears two-fold symmetry domains with a c-axis incline of about 31°along the[010]MgO or[010]MgO azimuth,indicative of an incline growth of c-axis.High-resolution TEM images show that both of 0 and Zn layer arrangement of the two kinds of incline domains is inverse.Moreover,Zn and Mg atoms appear diffusions each other at the interface,as demonstrated by the Energy Dispersive Spectrometer(EDS)and X-ray photoelectron spectroscopy(XPS).Interestingly,the inclined film exhibits bulk-like optical properties with a blue shift of about 0.083 eV due to the numerous Mg atom diffusions.This work provides a solid foundation to design and explore the novel optoelectronic devices based on the combinations between different structure and property materials.