Effect of Oxygen Partial Pressure on the Properties ZnO Film Grown on Macroporous Si by HF Magnetron Sputtering

In the present work, ZnO films were obtained on mesoporous silicon substrates by the method of HF magnetron sputtering of a metallic zinc target in reaction oxygen and argon gas medium. The effect of oxygen partial pressure on the structural and morphological characteristics of ZnO films has been studied. During the experiment, the oxygen pressure in the vacuum system was changed. The first series of experiments was carried out using pure oxygen at a pressure of 0.05 Pa. The second part of the macroporous Si samples was treatable at an oxygen pressure of 0.1 Pa. For Samples 1 the film thickness was 200 nm, for Samples 2 the film thickness was 400 nm. The results EDAX show that films with higher oxygen pressures contain more oxygen in the film composition. At an oxygen pressure of 0.1 Pa, the films have relatively good stoichiometry (the deviation between the Zn and O fractions in the films is 1.32%). The photoluminescence spectrum of the obtained structures consists of bands from the ZnO film in the region of near ultraviolet, green and yellow, as well as red light from the Si substrate. The maximum of the photoluminescence band excitation spectrum falls at 375 nm. This value coincides with the values of the band gap for bulk ZnO (3.35-3.3 eV). This PL spectrum indicates the structure of ZnO zinc blende, which corresponds to the X-ray study results of the obtained film crystal structure. The UV luminescence intensity of Samples 1 is lower than that of Samples 2. This is because ZnO Film Samples 2 covers a larger substrate surface than Samples 1 film. The spectra analysis shows that with an increase in the oxygen partial pressure, the luminescence spectra contain an additional peak in intensity at the edge of the spectrum violet part. In addition to PL in the near UV and violet areas, the structures exhibit intense luminescence in the green (560 nm) and yellow (580 nm) spectrum regions. The PL red band (640-650 nm) is associated with the porous silicon visible luminescence.