The formation and acceptor related emission behavior of ZnO/ZnAl2O4 core–shell structures

• Based on Kirkendall effect, a ZnO/ZnAl2O4 core–shell nanostructure were fabricated.
• Discussed the original of the PL spectrum in detail.
• A A0X emission peak was observed.
• Realize a undoped p-type ZnO.

In this paper, ZnO nanorods were grown on Si substrate with hydrothermal method, followed by Al2O3 and ZnO thin layers deposited on ZnO nanorods by atomic layer deposition, a coated nanocomposite structure ZnO/Al2O3/ZnO nanorods were obtained. Based on Kirkendall effect, ZnO/ZnAl2O4 core–shell nanostructure were fabricated by annealing treatment through an interfacial solid-state reaction between ZnO and Al2O3, which were confirmed by X-ray diffraction spectra. In this process, due to that Zn ions diffused into Al2O3 and formed ZnAl2O4, Zn vacancies were introduced in ZnO. In PL spectra, the emission related to acceptor located at 3.355 eV and 3.315 eV can be observed, which were attributed to A0X and FA emission, respectively. The calculated acceptor binding energy is 118 meV.