The study of undoped ZnO/p-Si (111) thin films prepared by R.F. magnetron sputtering

We report on the investigation of zinc oxide (ZnO) thin films grown on p-type silicon (111) substrate by radio frequency (RF) magnetron sputtering tool. The structural and optical characteristics of the sample have been investigated by using scanning electron microscope (SEM), atomic force microscope (AFM), high resolution X-ray diffraction (HR-XRD), Raman spectroscopy, photoluminescence (PL) and Fourier transform infra-red (FTIR), respectively. The FTIR measurement reveals that ZnO retains its wurtzite structure due to the presence of vibrations in the Zn-O bonds. XRD analysis shows that there exists a slight impurity occurring in the sample with the presence of Al₂O₃ and the high and sharp peak of ZnO shows the good quality of crystallinity of ZnO. Raman spectroscopy measurements reveal that the ZnO film is a single crystal and has wurtzite structure and the presence of impurities such as oxygen deficiencies and interstitial defects. The PL spectra clearly prove that the Zn has high crystal quality due to the very high and sharp peak at wavelength of 390 nm. The deep level emissions also show that there is an oxygen defects in the ZnO film. The deposition of ZnO film onto Si substrate through RF sputtering results in the ZnO film having high quality crystal structure with the presence some impurities and defects.