Not available

This Masters thesis investigates the effects of post growth rapid thermal annealing on colloidal CdTe nanoparticles. This novel process has not previously been applied to colloidal nanoparticles. It is found that rapid thermally annealing with temperatures up to 400°C, the number of defect bonds in the semiconductor core will decrease and the zincblende structural phase will prevail. These findings are identified using Raman spectroscopy enhanced in a liquid core waveguide and corroborated using a variety of other analysis techniques. What is also important is that while the semiconductor core is changing, the optical characteristics of the material remain nominally unchanged. Additionally, a circulatory peristaltic pump system that is suitable for future in situ monitoring was developed and used to investigate the length effects of Teflon capillary tubes as a liquid core waveguide for Raman spectroscopy.

This Masters thesis investigates the effects of post growth rapid thermal annealing on colloidal CdTe nanoparticles. This novel process has not previously been applied to colloidal nanoparticles. It is found that rapid thermally annealing with temperatures up to 400°C, the number of defect bonds in the semiconductor core will decrease and the zincblende structural phase will prevail. These findings are identified using Raman spectroscopy enhanced in a liquid core waveguide and corroborated using a variety of other analysis techniques. What is also important is that while the semiconductor core is changing, the optical characteristics of the material remain nominally unchanged. Additionally, a circulatory peristaltic pump system that is suitable for future in situ monitoring was developed and used to investigate the length effects of Teflon capillary tubes as a liquid core waveguide for Raman spectroscopy.

Frankfurt (Main), Univ., Diss., 2009 / Erscheinungsjahr an der Hauptitelstelle: 2008

Thesis (doctoral)--University of Konstanz, 2004. / Includes bibliographical references (p. 157-173).

No description available.

published_or_final_version / Physics / Doctoral / Doctor of Philosophy

A novel method of synthesizing and controlling the size of germanium nanocrystals was developed. A tri-layer structure comprising of a thin (~5nm) SiO₂ layer grown using rapid thermal oxidation (RTO), followed by a layer of Ge+SiO₂ of varying thickness (6 - 20 nm) deposited using the radio frequency (r.f.) co-sputtering technique and a SiO₂ cap layer (50nm) deposited using r.f. sputtering, was investigated. It was verified using TEM that germanium nanocrystals of sizes ranging from 6 – 20 nm were successfully fabricated after thermal annealing of the tri-layer structure under suitable conditions. The nanocrystals were found to be well confined by the RTO SiO₂ and the cap SiO₂ under specific annealing conditions. The electrical properties of the tri-layer structure have been characterized using MOS capacitor test devices. A significant hysteresis can be observed from the C-V measurements and this suggests the charge storage capability of the nanocrystals. The proposed technique has the potential for fabricating memory devices with controllable nanocrystals sizes. / Singapore-MIT Alliance (SMA)

Following the concept utilize binary selenides as precursors with rapid thermal process (RTP) to fabricate CuInSe2 (CIS) thin film. In order to find the most promise process to get high quality CIS, several precursor stacking sequences have been tested which including SLG/In-Se/Cu-Se/Se, SLG/Cu-Se/In-Se/Se, SLG/0.1In-Se/Cu-Se/0.9/In-Se/Se, and SLG/0.5In-Se/Cu-Se/0.5/In-Se/Se, and the experiment result shows SLG/In-Se/Cu-Se/Se is the most suitable stacking sequence. Subsequently, varying Se flux to obtain several kinds copper selenides (Cu7Se4, Cu3Se2, CuSe, CuSe2) and indium selenides, try to find the suitable pairs through these binary selenides in SLG/In-Se/Cu-Se/Se structure. The suitable combination phase in Cu-Se precursor layer is CuSe blend with CuSe2. Large grain size CIS, about 1£gm, can be prepared in such precursor phase with film thickness between 700nm to 1£gm, strong (112) prefer-orientation vertical with substrate as well as good adhesion. Films were characterized through scanning election microscopy (SEM) to obtain grain size, surface morphology as well as film thickness. The X-ray diffractometer (XRD) was used to identify phase contained in whole film, and the phase constitution near surface layer was examined by Raman spectroscopy. If there are some second phases remaining in the thin film, combining the phase examination result of XRD and Raman spectroscopy, it can be estimate the second phase exist in the surface layers or internal film area.

No description available.