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P-type delafossite CuGaO2 is a wide-bandgap semiconductor for optoelectronic applications, and its lattice parameters are very similar to those of n-type semiconductor wurtzite ZnO. Accordingly, the investigation of crystalline heterostructures of CuGaO2 and ZnO has attracted significant attention. In this study, interfacial CuGaO2/ZnO hetero-compounds were examined through X-ray diffraction (XRD) analysis, confocal micro-Raman spectroscopy, and X-ray photo-electron spectroscopy (XPS). XRD and Raman analysis revealed that the hydrothermal deposition of ZnO on hexagonal platelet CuGaO2 base crystals was successful, and the subsequent reduction process could induce a unique, unprecedented reaction between CuGaO2 and ZnO, depending on the deposition parameters. XPS allowed the comparison of the binding energies (peak position and width) of the core level electrons of the constituents (Cu, Ga, Zn, and O) of the pristine CuGaO2 single crystallites and interfacial CuGaO2/ZnO hybrids. The presences of Cu2+ ions and strained GaO6 octahedra were the main characteristics of the CuGaO2/ZnO hybrid interface. The XPS and modified Auger parameter analysis gave an insight into a specific polarization of the interface, promising for further development of CuGaO2/ZnO hybrids.

P-type delafossite CuGaO2 is a wide-bandgap semiconductor for optoelectronic applications, and its lattice parameters are very similar to those of n-type semiconductor wurtzite ZnO. Therefore, the investigation on p-n junction properties of crystalline CuGaO2 /ZnO heterostructures has attracted significant attention. In this study, interfacial CuGaO2 /ZnO heterojunctions were examined through X-ray diffraction (XRD) analysis, confocal micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XRD analysis revealed that the hydrothermal deposition of ZnO on hexagonal platelet CuGaO2 base crystals was successful, and the subsequent reduction process could induce a unique reaction between CuGaO2 and ZnO. XPS allowed the comparison of the binding energies (peak position and width) of the valence electrons of the constituents (Cu, Ga, (Zn) and O) of the pristine CuGaO2 single crystallites and of crystalline CuGaO2 /ZnO heterojunctions. The presence of distorted GaO6 octahedra at the CuGaO2 /ZnO hybrid interface and the absence of Cu2+ ions were the main characteristics of the chemically well-reconstructed heterojunction interface that facilitated effective carrier separation.

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