| Summary: | 碩士 === 國立交通大學 === 材料科學與工程學系所 === 102 === This thesis focuses on growth of (111) homoepitaxial diamond films with embedded silicon-based quantum dots (QDs) and analyses of related properties. The first part of this thesis deals with SiOx film deposited by magnetron sputtering, and the evolution of SiOx after treatment of hydrogen plasma. The second part emphasizes on Si-based QDs, which are transformed from SiOx after diamond film growth. Properties of CVD diamond film and silicon-based QDs are analyzed and discussed as well.
First of all, sputtered SiOx films were obtained after sputtering a Si target with Ar plasma in high vacuum. The films were characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy, photoluminescence (PL), and X-ray diffraction analysis (XRD) for crystallinity and chemical compositions. The SiOx films deposited on the surface of single crystalline diamond (111) substrate exhibited particle-like morphology after hydrogen plasma treatment. The particle size decrease with increasing the duration of hydrogen plasma treatment.
After growth of CVD diamond films, the amorphous SiOx quantum dots (QDs) around 4nm in size were formed and embedded in diamond as shown by transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). Also, TEM and XRD results show that the deposited diamond films in homoepitaxy are grown through epitaxial lateral overgrowth (ELO) on SiOx QDs. The quality of diamond films was slightly decreased by embedded QDs; however, the QDs have a small but significant effect on relaxation of film stress which may result in formation of cracks in diamond film in thicker films than those grown on substrate without SiOx coating. Sub-angstrom probe STEM-EDS analyses reveal that the embedded QDs have a composition of SiO0.6. PL measurements show that the emission peak from the QDs exhibit blue shift in the wavelength range of 510-536 nm, with the decrease of the QD size due to the quantum confinement effect.
|
|---|
