Structural and optical properties of annealed CdO thin films prepared by spray pyrolysis

CdO films were prepared on glass substrates by the spray pyrolysis technique. Results on structural, optical and electrical properties of the layers as a function of the thermal annealing are reported. XRD data indicates that samples show microstructural perfection improvement as a function of annealing time. The optical band-gap shows a dependence with the inverse of the squared crystallite size, suggesting that electron confinement is an important effect. The lattice parameter and band-gap energy of the samples annealed at 450 degreesC for 120 min correspond to the reported values of bulk CdO crystals. In addition, the electrical resistivity measurement shows a slight decrease when annealing time is increased up to 40 min but it saturates for larger times. (C) 2001 Elsevier Science B.V, All rights reserved.