Room-temperature electrosynthesized ZnO thin film with strong (0 0 2) orientation and its optical properties

ZnO thin film with strong orientation (0 0 2) and smooth surface morphology was electrosynthesized on ITO-coated glass substrate at room temperature under pulsed voltage. Photoluminescence (PL) shows two obvious peaks: violet band and strong green band. The former is due to the free-excitonic transition and the latter is believed to arise from the single ionized oxygen vacancy (VO+). Raman scattering reveals that the 580 cm−1 mode and the shoulder peak mode at 550 cm−1 originate from the N-related local vibration mode (LVM) and E1 (LO) mode, respectively.