Behaviour of Charge Carriers in As-Deposited and Annealed Undoped TCO Films

We examine the structures, cut-off points of transmittance spectra and electric properties of undoped ZnO, SnO₂ and CdO films by scanning electron microscopy, x-ray diffraction, spectrophotometer and Hall-effect measurements, respectively. The films are deposited by using an rf magnetron sputtering system from powder targets in argon and then annealed in vacuum. The structures and properties of the as-deposited films are compared with those of the annealed one. We try to explain the behaviour of charge carriers based on the semiconductor physics theory.