Electro-optical characterization of ZnO/ZnMgO structure grown on p-type Si (1 1 1) by PA-MBE method

Abstract We report on the electro-optical properties of ZnO-based heterojunction with i-ZnO layer. The structure was grown on (1 1 1) p-Si by plasma-assisted molecular beam epitaxy at 570 °C. Quality of the obtained epilayers was verified by X-ray diffraction. Optical properties of the heterostructures were studied by photo- and cathodoluminescence. Photoluminescence spectra were measured within temperature range of 5.4–300 K and cathodoluminescence measurements were performed at room temperature. A defect-related radiative recombination was observed. In order to recognize the origin of the defects, responsible for the radiative recombination process, electrical measurements were performed on a diode of ZnMgO:N/i-ZnO/n-ZnMgO. Rectifying properties of the junction were confirmed by the current–voltage ( I – V ) and capacitance–voltage ( C – V ) measurements. Metastability of the I – V characteristics as well as persistent photocapacitance observed within a temperature range of 40–280 K were explained by the presence of metastable defects, presumably related oxygen vacancies, and slow interface states.