SOME PHYSICAL-PROPERTIES OF ZNO SPUTTERED FILMS

The secondary electron emission (SEE) yield delta of ZnO films was investigated. The films were deposited in an rf sputtering system using the rf power W, the argon pressure p, the O//2 partial pressure p//O//2 and the substrate temperature T//s as parameters. Complementary measurements of the electrical resistivity rho and the optical absorption alpha were performed. The ratio x of oxygen to zinc is an essential factor which determines the values of +67, rho and alpha for the ZnO films. Auger analyses showed that excess (overstoichiometric, x greater than 1) oxygen is present in ZnO films obtained at room temperature. For x greater than 1 the values of rho , the maximum SEE yield delta //m and the energy band gap E//g (determined from alpha ) were found to be higher than those for stoichiometric ZnO (obtained at T//s greater than 200 degree C).