In this study, we used ion implantation technique to synthesize semiconductor
(Ge, Si) nanocrystals in SiO2 matrix. Ge and Si nanocrystals have been
successfully formed by Ge and Si implantation and post annealing. Implanted
samples were examined by characterization techniques such as TEM, XPS, EDS,
SAD, SIMS, PL, Raman and FTIR spectroscopy and the presence of Ge and Si
nanocrystals in the SiO2 matrix has been evidenced by these measurements. It
was shown that implantation dose, implantation energy, annealing temperature,
annealing time and annealing ambient are important parameters for the formation
and evolution of semiconductor nanocrystals embedded in SiO2 matrix. The
size and size distribution of Ge and Si nanocrystals were estimated successfully
by fitting Raman and PL spectra obtained from Ge and Si implanted samples, respectively. It was demonstrated that Si implanted and post annealed samples
exhibit two broad PL peaks at & / #8764 / 625 and 850 nm, even at room temperature.
Origin of these peaks was investigated by temperature, excitation power and excitation
wavelength dependence of PL spectrum and etch-measure experiments
and it was shown that the peak observed at & / #8764 / 625 nm is related with defects
(clusters or chain of Si located near the surface) while the other is related to the
Si nanocrystals. As an expected effect of quantum size phenomenon, the peak
observed at & / #8764 / 850 nm was found to depend on the nanocrystal size. Finally,
the formation and evolution of Ge and Si nanocrystals were monitored by FTIR
spectroscopy and it was shown that the deformation in SiO2 matrix caused by
ion implantation tends to recover itself much quicker in the case of the Ge implantation.
This is a result of effective segregation of Ge atoms at relatively low
temperatures.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12605016/index.pdf |
| Date | 01 June 2004 |
| Creators | Serincan, Ugur |
| Contributors | Turan, Rasit |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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