Temperature Dependent Charge Transport Properties Of P-type Cux(CdTe)yOz Films Studied By Au Ohmic And Schottky Contacts

Temperature dependent current voltage measurements were done on five samples of Cu-x(CdTe)(y)O-z grown by reactive rf cosputtering. The stoichiometry of the samples were different and in the high copper and oxygen concentrations regime. An Al and a Au contact were used. The Al contact was always ohmic. Depending on the composition, the Au contact yielded either a Schottky or an ohmic behavior. In the case of an ohmic behavior, one sample yielded temperature independent results, while another temperature dependent parameters. In the case of Schottky behavior, the Cheung method was used to obtain the internal resistance and the ideality factor. The current voltage behavior is well explained by tunneling, and three activation energies of 62, 89 and 186 meV are obtained for each sample. Finally, a negative differential resistance effect is found in one sample, the only one where it was possible to detect CuO and Cu2O nanoclusters using the X-ray diffraction technique.