Characterization of n-type ZnO:Al Films grown by Magnetron Sputtering

摘要

ZnO is a wide band gap semi-conductor that has attracted tremendous interest for itspotential applications in optoelectronic, solar cell, gas detection ...In this work, aluminium doped zinc oxide (ZnO:Al) films were deposited by RF magnetronsputtering on glass substrates with different RF power densities of 1.2, 2.5, 3.7 and 4.9 W/cm~2. Wenotice that the films grown at 1.2 W/cm~2 were very thin and their physical properties were notprecisely determined. The electrical properties of ZnO films were investigated using the impedancespectroscopy technique in the frequency range from 5 Hz to 13 MHz. The impedance data,represented by Nyquist diagrams showed that the resistivity of the films changed during the firstthree months after deposition.The deposited films show good optical transmittance (over 80 %) in the visible and near infraredspectra. The band gap is around 3 eV and decreases with the increasing of the RF power density(from 3.35 to 3.05 eV).The results of this study suggest that the variation of the RF power density used for depositionallow the control of the electrical and optical properties of the films.