Effect of oxygen pressure on electrical properties of Ge-doped ZnO thin films grown by using pulsed laser deposition

摘要

ZnO and Ge-doped ZnO (GZO) thin films were fabricated on c-Al _2O _3 substrates at various oxygen pressures (10, 50, 100, 200, and 400 mTorr) and at 300 °C by using a pulsed laser deposition method. The transmittances of the films were measured by using ultraviolet-visible spectroscopy. The absorption of the band gap edge was calculated by using Tauc's equation. The films showed n-type conduction characteristics. Compared to the other films, the film deposited at 10 mTorr compared showed improved electrical properties. The carrier concentration and the resistivity of the GZO film were 10 ~(21) cm ~(-3) and 6. 5 × 10 ~(-4) Ωcm, respectively.