Effects of substrate temperature on crystallinity and electrical properties of Ga-doped ZnO films prepared on glass substrate by ion-plating method using DC arc discharge

The effects of substrate temperature, T-s, on the crystallinity and the electrical properties of Ga-doped ZnO films (GZO) with a thickness of 200 nm were investigated. GZO films were prepared on glass substrates at various T-s in the range from 150 to 400 degrees C by ion-plating method with DC are discharge. X-ray diffraction analysis reveals that GZO film prepared at 250 degrees C shows the preferential orientation of c-axis and the highest crystallinity. Williamson-Hall analysis indicates that the crystallite size of GZO films remains nearly constant with increasing T-s up to 300 degrees C, and then, with further increasing T-s decreases gradually. The Ga concentration in the films, estimated by secondary ion mass spectroscopy and X-ray fluorescence analyses, increases monotonically with increasing T-s above 250 degrees C. Hall effect measurements show that resistivity decreases slightly with increasing T, up to 250 degrees C, leading to the lowest resistivity of 2.1 x 10(-4) Omega cm at 250 degrees C, and then exhibits a gradual increase with further increasing T-s. (c) 2007 Elsevier B.V. All rights reserved.