Investigation of terbium-doped silicon oxide thin films: comparison of TEM images prepared by FIB and mechanical methods

This study characterizes the optical and structural properties of terbium-doped oxygen-rich silicon oxide (ORSO:Tb) thin films and investigates focused ion beam (FIB)-induced damage on transmission electron microscopy (TEM) lamellae prepared from these films. While there are significant advantages to the FIB technique, there is a potential that energetic ions used during the FIB process can damage the lamellae. A comparative analysis of TEM images obtained using FIB and conventional mechanical preparation methods was performed. The results indicate that TEM images of FIB-prepared lamellae exhibit higher resolution, allowing for a more detailed examination of nanocrystal structures and quantum dots. In contrast, the lack of sufficient clarity of the mechanically prepared TEM images reduces the number of nanocrystals visible in the field of view, resulting in a less effective and detailed study of the thinned films. We found no evidence of Ga implantation or mixing into the thinned film, and no observable FIB-induced damage such as recrystallization, or amorphization. Photoluminescence spectra exhibited red and blue shifts with increasing annealing temperature at blue and green emissions, respectively. X-ray diffraction patterns verify that the formation of crystalline nanostructures begins at 1100 °C, and at least at 1200 °C, two phases of Tb4Si3(SiO4)O10 and Tb2O3 in the sample are recognized.