Thesis (Ph. D.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains xii, 116 p. : ill. Includes abstract. Includes bibliographical references (p. 106-109).

Thesis (doctoral)--Technische Universiteit Delft, 2000. / Includes bibliographical references (p. 123-130).

Time-resolved photoluminescence (TRPL) measurements paired with steady-state photoluminescence (SSPL) measurements can help to determine the PL lifetime, shape and position of unresolved bands, capture coefficients, and concentrations of free electrons and defects.PL bands that are obscured in the SSPL spectra can be accurately revealed by TRPL measurements. TRPL measurements are able to show if the PL band originates from an internal transition between different states of the same defect. The main defect-related PL bands in high-purity GaN grown by hydride vapor phase epitaxy (HVPE) which have been investigated are the ultraviolet, blue, green, yellow and red luminescence bands (UVL, BL, GL, YL and RL, respectively). The concentration of free electrons can be calculated from these measurements providing a contactless alternative to the Hall effect method. The lifetime of most defect-related PL bands decreases with increasing temperature. However, the lifetime of the GL band, with a maximum at 2.4 eV observed in the SSPL spectra only at high excitation intensity, increases as a function of temperature. By analyzing the PL intensity decay, the origin of the GL can be attributed to an internal transition from an excited state of the CN defect, which behaves as an optically generated giant trap, to the 0/+ level of the same defect. This first observation of an optically generated giant trap was detected by analyzing the cubic temperature dependence of the electron capture coefficient. Excitation intensity and temperature dependent studies on Mg-doped GaN grown by HVPE were performed. The position of the UVL (3.2 eV) peak blue-shifts with increasing excitation intensity, which can be explained by the presence of potential fluctuations. The BL peak (2.8 eV) also blue-shifts with increasing excitation intensity, and red-shifts as a function of temperature. These shifts can be explained by the transitions originating from a deep-donor to the MgGa acceptor, and the corresponding donor-acceptor pair nature.

Esta dissertação mostra a análise da interação de intersticiais pesados como oxigênio e nitrogênio em amostras policristalinas de nióbio e monocristalinas de nióbio e tânalo. Os dados experimentais foram obtidos através de medidas de atrito interno e freqüência de oscilação do pêndulo em função da temperatura, utilizando-se um pêndulo de torção invertido tipo Kê. Os resultados mostram estruturas de relaxação atribuídas à reorientação induzida por tensão de átomos intersticiais em torno de átomos da matriz metálica. Estas estruturas forma analisadas através de dois métodos: subtrações sucessivas e tempo de relaxação. A partir das medidas de atrito interno foram identificados os processos de relaxações Nb-O, Nb-N e Ta-O. Esses mesmos processos de relaxação foram confirmados por meio das medidas de freqüência de oscilação do pendulo usando um método proposto nesta dissertação, o qual relaciona o quadrado dessa freqüência medida e o inverso da temperatura. / This dissertation shows the analysis of heavy interstitials interaction, such as oxygen and nitrogen, in a policrystalline niobium sample and single crystal samples of niobium and tantalum. The experimental data were obtained by internal friction and oscillation frequency measurements as a function of temperature, using a Kê-type inverted torsion pendulum. The results show relaxation structures attributed to stress induced ordering of interstitial atoms around the mettalic matrix atoms. These structures were analysed by two methods: sucessive subtraction and relaxation time. From internal friction measurements, Nb-O, Nb-N and Ta-O relaxation processes were identified. These same relaxation processes were confirmed by oscillation frequency measurements, using a method proposed here, which relates squared frequency with inverse of temperature.

by Chan Kwok Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 93-95). / ACKNOWLEDGEMENT --- p.i / ABSTRACT --- p.ii / LIST OF SYMBOLS --- p.iii / LIST OF FIGURES --- p.v / LIST OF TABLES --- p.vi / Chapter CHAPTER ONE --- INTRODUCTION --- p.1 / Chapter CHAPTER TWO --- SURVEYS ON ION IMPLANTATION DAMAGE STUDY --- p.6 / Chapter 2.1 --- Introduction --- p.6 / Chapter 2.1.1 --- Basic Theory --- p.7 / Chapter 2.1.2 --- Amorphization --- p.9 / Chapter 2.1.3 --- Amorphous Layer Regrowth --- p.10 / Chapter 2.1.4 --- Point Defect Sources --- p.11 / Chapter 2.1.5 --- Types of Extended Defects --- p.11 / Chapter 2.2 --- Nature of Point Defects --- p.15 / Chapter 2.2.1 --- Important Parameters --- p.15 / Chapter 2.2.2 --- Vacancy Centers in Semiconductor --- p.16 / Chapter 2.2.3 --- Self-interstitial in Silicon --- p.17 / Chapter 2.2.4 --- Distribution of Excess Point Defects --- p.18 / Chapter 2.2.5 --- Energy Level of Defect Species --- p.19 / Chapter CHAPTER THREE --- EXPERIMENTAL METHOD --- p.21 / Chapter 3.1 --- Experimental --- p.21 / Chapter 3.2 --- Spreading Resistance Profiling --- p.25 / Chapter CHAPTER FOUR --- MODELING OF SPREADING RESISTANCE PROFILES OF ION-IMPLANTED DAMAGE IN SILICON --- p.29 / Chapter 4.1 --- Introduction --- p.29 / Chapter 4.2 --- Basic equation --- p.30 / Chapter 4.3 --- Formation of Model --- p.34 / Chapter CHAPTER FIVE --- RESULTS AND DISCUSSION --- p.37 / Chapter 5.1 --- Results --- p.37 / Chapter 5.2 --- Discussion --- p.55 / Chapter CHAPTER SIX --- CONCLUSION AND SUGGESTIONS OF FURTHER WORK --- p.58 / Chapter 6.1 --- Conclusion --- p.58 / Chapter 6.2 --- Suggestions of further work --- p.59 / APPENDIX A --- p.60 / APPENDIX B / SPREADING RESISTIVITY PROFILES --- p.62 / REFERENCE --- p.93

We have studied the introduction of defects in silicon wafers with low dose channelling ion implantation. (For complete abstract open document)

Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Feb. 11, 2009; title from PDF t.p. Includes bibliographical references (p. 49-50).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains viii, 71 p. : ill. Includes abstract. Includes bibliographical references (p. 70-71).

Contents: a. The oxidation of metals by atomic and molecular oxygen -- b. Calculation of the heats of formation of point defects in some transition metal oxides.

Made available in DSpace on 2014-10-09T12:24:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:08Z (GMT). No. of bitstreams: 1 00022.pdf: 993127 bytes, checksum: bac5ce8c3db6e5141db1915bfb8efbb1 (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Fisica, Universidade de Sao Paulo - IF/USP