INSTITUTO DE FISICA LA PLATA
Unidad Ejecutora - UE
congresos y reuniones científicas
Perturbed Angular Correlation Experiments on â-Ga2O3 thin films
MICHAEL STEFFENS; CECILIA Y. CHAIN; ALBERTO F. PASQUEVICH; REINER VIANDEN
Conferencia; 4th Joint Meeting of the International Conference on Hyperfine Interactions and the International Symposium on Nuclear Quadrupole Interactions (HFI/NQI 2012); 2012
China Institut of Atomic Energy
The hyperfine interactions of 111In/111Cd in â-Ga2O3 thin films were studied as a function of temperature by means of the Perturbed Angular Correlation technique. The films were prepared by furnace oxidation of commercially available GaN thin films grown on silicon substrates. Previously to the oxidation the GaN films were implanted with 111In (160 keV). PAC spectra were taken at room temperature after annealing the samples in Ar atmosphere to remove radiation damage. The well known signal of 111In in GaN was observed. Room temperature PAC spectra were taken after oxidation treatments of 5 min. in air at 800 °C. After 50 min. of treatment the signal of indium probes in GaN disappears. Subsequent treatments do not change the spectra. They can be fitted assuming that all the probes are in the â-Ga2O3 structure occupying one of the available cation sites. It is known that indium has a preferential occupation for the site with octahedral coordination of oxygens. Additionally, the spectra are attenuated as a result of a time dependent interaction. This interaction disappears when increasing the measurement temperature. This effect has been observed in others transparent conductive oxides. Normally the used arguments for explaining the effect involve aftereffects of the preceding electron capture decay of 111In conjugate with the acceptor character of Cd ?impurity center in these oxides. In the present communication, the PAC results from films obtained by ?furnace oxidation? are compared with those of the bulk material, in poly or single crystalline form. Additionally, besides the results of the quoted experiments, a model for explaining them is presented.