Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5368707 | Applied Surface Science | 2006 | 6 Pages |
TiO2 thin films were prepared under various conditions by using a reactive RF sputtering technique. The structural, optical and electrical characteristics of the films have been investigated. All as-deposited films were amorphous. After annealing at T > 673 K, the crystallinity of the observed tetragonal anatase phase appeared improved. The optical band gap, determined by using Tauc plot, has been found to amount to 3.38 ± 0.03 and 3.21 ± 0.03 eV for the direct and indirect transition, respectively. Also the complex optical constants for the wavelength range 300-2500 nm are reported. Using the two-point probe technique, the dark resistivity has been measured as a function of the film thickness, d. The resistivity, Ï, of the samples has been found to decrease markedly with increasing thickness, but only for d < 100 nm. The behaviour of Ïd versus d was found to fit properly with the Fuchs and Sondheimer relation with parameters Ïo = 4.95 Ã 106 Ω cm and mean free path, l = 310 ± 2 nm. The log Ï versus 1/T curves show three distinct regions with values for the activation energy of 0.03 ± 0.01, 0.17 ± 0.01 and 0.50 ± 0.02 eV, respectively.