Structural, electrical, and optical properties of Na-doped ZnO thin films deposited by pulsed laser deposition

Na-doped ZnO thin films were deposited on quartz substrates at various temperatures by using pulsed laser deposition technique. An X-ray diffractometer and an atomic force microscope were used to investigate the structural and morphological properties of the thin films. A Hall effect measurement system was used to investigate the electrical properties of the thin films. A spectrophotometer was used to measure the transmittances of the thin films. The band gap energies of the thin films were calculated by linear fitting the sharp absorption edge for high-quality thin film. The band gap energies of the Na-doped ZnO thin films are nearly the same as the pure ZnO. A spectrometer was used to investigate the luminescent properties of the thin films. The thin film deposited at 200 degrees C had no near band edge emission and no deep-level emission. The NBE emission appeared and increased with increasing the growth temperature.