Both intrinsic and extrinsic defects of hafnium oxide films are investigated based on photoluminescence ͑PL͒ and cathodoluminescence ͑CL͒ measurements. Instead of using the high-power synchrotron radiation or ArF excimer laser sources, a hydrogen-deuterium lamp ͑HDL͒ was used for the PL measurements to avoid the possible generation of active oxygen and hydroxyl ions. Results show that the HDL PL spectra generally agree with those registered using the conventional high-power excitation sources. CL spectra also agree with the PL ones. Narrow emission band at peak energy of 4.0 eV, which is ascribed to the vibronic transition of excited OH ·* radical, was found using photoluminescence excitation and at energy of 4.25 eV.
The g and g* phases of alumina synthesized from crystalline boehmite and pseudoboehmite were shown to strongly differ in some physicochemical characteristics. Photoluminescence of Cr 3+ and Fe 3+ as luminescent probes with their natural impurity concentrations was detected in the tested alumina samples and the local structure of the samples was examined. The crystal field strength and Racah parameters in g-Al 2 O 3 phases were determined. The ratio of octahedral and tetrahedral cationic positions was equal to 1 for g-Al 2 O 3 synthesized from crystalline boehmite, and 0.3 for that obtained from pseudoboehmite. The effect of residual OH groups and weakly bound molecular water on the local structure of g-Al 2 O 3 phases was revealed. The luminescence of Cr 3+ was detected in subsurface structures of each alumina; defects produced by nanocrystallites were shown to affect the luminescence.
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