Cathodoluminescence study of gadolinium-doped yttrium oxide thin films deposited by radio-frequency magnetron sputtering

A multi-layer gadolinium-doped yttrium oxide thin film was deposited in a combinatorial fashion on a Si (001) substrate using radio-frequency magnetron sputtering. Alternating layers of Y2O3 and Gd were deposited for a total of 9 layers. The film was homogenized in composition by an 850 C 12 hour thermal treatment producing a range of composition from Y1.96Gd0.04O3 - Y1.54Gd0.46O3 in a single film. Ultraviolet emission with a peak wavelength at 314-315nm was observed from the gadolinium S-8(7/2) - P-6(7/2) transition via cathodoluminescence (CL) excitation. The CL-induced intensity was found to be maximum at 9 at% Gd (Y1.82Gd0.18O3) and an optimized electron probe of V-acc = 13 keV was determined for the 1 mum thick thin film. Gadolinium activator saturation was observed for sample current density greater than 0.03 muA/cm(2). Non- radiative decay via thermal pathways is suspected for the observed activator saturation.