Influence of Sputtering Time on the Properties of CdSe Thin Films Prepared by Annealing the Precursors

CdSe thin films are prepared through sputtering‐evaporation‐sputtering (SES) deposition combined with annealing. Effect of sputtering time on the properties of CdSe films is studied using X‐ray diffraction, field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy, UV‐visible spectrophotometer, fluorescence spectrometer, and positron annihilation Doppler broadening spectroscopy. The results show that the SES precursors are transformed into hexagonal CdSe films. CdSe films have the crystal size of 34–47 nm and the Se/Cd atomic ratio of 0.54–0.76 with increasing sputtering time. With sputtering time = 3 min, CdSe films have uniform and dense surfaces. The CdSe thin films have a high transmission with optical bandgaps of 1.60–1.64 eV. These films exhibit a photoluminescence (PL) emission peak at 782 nm caused by band‐to‐band transitions, as well as a PL emission peak at 829 nm caused by vacancies. The surface defects of all CdSe films are less than those of their inner, and with increasing sputtering time to 5 min, defect types become complex.