Ultraviolet emitting (Y1−xGdx)2O3 − δ thin films deposited by radio frequency magnetron sputtering; structure-property-thin film processing relationships

The effects that the oxygen partial pressure, substrate temperature and annealing temperature have on the cathodoluminescence (CL) efficiency of radio frequency magnetron sputter deposited Gd-doped Y2O3 thin films is investigated. Furthermore these sputtering parameters are correlated to the degree of crystallinity, the phases present (cubic (α) versus monoclinic (β) Y2O3), and the stoichiometry of the thin films. Films deposited at room temperature (RT) did not CL, however, the films were activated by a post-deposition anneal at 1273 K for 6 h. Films deposited at 873 K had a very low CL efficiency which was significantly enhanced by a post-deposition anneal. For RT deposited films the external CL efficiency increased with increasing oxygen partial pressure for the range studied, however the opposite trend was observed for the 873 K deposited films. Examination of the morphology and grain size of the high temperature deposited films revealed that the average grain size increased with decreasing partial pressure and the observed increase in the external CL efficiency was attributed to enhanced anomalous diffraction. An intrinsic CL efficiency term was determined to circumvent the effects of the enhanced anomalous diffraction, and the CL efficiency was correlated to the integrated intensity of the (222) of the cubic α-Y2O3 phase.