| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系所 === 97 === This work prepares the nanocomposite thin films containing GaN quantum dots (QDs) in Si3N4 and SiOxNy dielectric matrices by using the target-attached sputtering method. Transmission electron microscopy （TEM） revealed the presence of GaN QDs in the both types of thin-film systems. Although the dot density increases with the number of the target-attached pellets, the dot size is independent of that. Electron spectroscopy for chemical analysis（ESCA）and photoluminescence（PL） analyses indicated that the SiO2 matrix may react with N2 injected during sputtering and generate the SiOxNy. It generates a distinct bonding configuration on GaN QDs surface and induces a stronger surface polarization in GaN QDs-SiOxNy system in comparison with the GaN QDs-Si3N4 system. This, in turn, suppresses the yellow-green transition relating to VGa on GaN QDs. Meanwhile, a specific optical transitions, which improves the defect luminescent intensity due to the diminishing of near-band-edge signals, when the volume ratio of GaN QDs to matrix is about 1:1 in both systems. Although present data are insufficient to correlate the optical transition in complete manner, the results above indeed illustrate that the dielectric matrix type has an important effect on the optical properties of nanocomposite thin films.
|
|---|
