Thesis (Ph. D.)--Lehigh University, 2001. / Includes bibliographical references and vita.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 16-19, 108-110, 157-159, 203-205, 270-272, 315-316, 337).

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--Lehigh University, 1997. / Includes vita. Includes bibliographical references.

Thesis (PhD)--Macquarie University, School of Mathematics, Physics, Computing and Electronics, 1999. / "1998"--T.p. Includes bibliographical references.

The structural properties of the group III-nitrides including AlN, Ga1-xMnxN, GaN:Cu, and InN were investigated by Raman spectroscopy. Absorption and photoluminescence spectroscopy were utilized to study the optical properties in these materials. The analysis of physical vapor transport grown AlN single crystals showed that oxygen, carbon, silicon, and boron are the major impurities in the bulk AlN. The Raman analysis revealed high crystalline quality and well oriented AlN single crystals. The absorption coefficient of AlN single crystals were assessed in the spectral range from deep UV to the FIR. The absorption and photoluminescence analysis indicate that, in addition to oxygen, carbon, boron, and silicon, contribute to the optical properties of bulk AlN crystals. In situ Cu-doped GaN epilayers with Cu concentrations in the range of 2x10^16 cm-3 - 5x1017 cm-3, grown on sapphire substrate by metal organic chemical vapor deposition, were investigated by Raman and PL spectroscopy. The Raman study revealed high crystalline GaN:Cu layers with minimal damage to the hexagonal lattice structure due to the Cu incorporation. A strong Cu related emission band at 2.4 eV was assigned to Cu induced optical transitions between deep Cu states and shallow residual donor states. Compensation of Cu states by residual donors and poor activation probability of deep Cu states are responsible for semi-insulating electrical conductivity. Ferromagnetic Ga1-xMnxN epilayers, grown by MOCVD with Mn concentration from x = 0 to x = 1.5, were optically investigated by Raman, PL, and transmission spectroscopy. The Raman studies revealed Mn-related Raman peaks at 300 cm-1, 609 cm-1, and 669 cm-1. Mn-related absorption and emission bands in Ga1-xMnxN were observed at 1.5 eV and 3.0 eV, respectively. The structural properties of InN layers, grown by high pressure-CVD with different free carrier concentrations, were analyzed by Raman spectroscopy. The Raman results show that the InN layers have high crystalline quality. The free carriers in layers were calculated by using the Lindhard-Mermin dielectric function taking into account finite wave vectors for various scattering processes including forbidden Frohlich, deformational potential associated with allowed electro-optic, and charge density fluctuation, mechanisms. The free carrier concentrations in the layers are below 1x10^20 cm-3.

Thesis (Ph. D. in Electrical Engineering)--Vanderbilt University, May 2009. / Title from title screen. Includes bibliographical references.

No description available.

"1998"--T.p. / Thesis (PhD)--Macquarie University, School of Mathematics, Physics, Computing and Electronics, 1999. / Includes bibliographical references. / Introduction -- A Michelson interferometer for measurement of piezoelectric coefficients -- The piezoelectric coefficient of gallium arsenide -- Extensional piezoelectric coefficients of gallium nitrides and aluminium nitride -- Shear piezoelectric coefficients of gallium nitride and aluminium nitride -- Electrostriction in gallium nitride, aluminium nitride and gallium arsenide -- Summary and prognosis. / The present work represents the first use of the interferometric technique for determining the magnitude and sign of the piezoelectric coefficients of III-V compound semiconductors, in particular gallium arsenide (GaAs), gallium nitride (GaN), and aluminium nitride (AIN). The interferometer arrangement used in the present work was a Michelson interferometer, with the capability of achieving a resolution of 10⁻¹³ m. -- The samples used were of two types. The first were commercial wafers, with single crystal orientation. Both GaAs and GaN were obtained in this form. The second type of sample was polycrystalline thin films, grown in the semiconductor research laboratories at Macquarie University. GaN and AIN samples of this type were obtained. -- The d₁₄ coefficient of GaAs was measured by first measuring the d₃₃ value of a [111] oriented sample. This was then transformed to give the d₁₄ coefficient of the usual [001] oriented crystal. The value obtained for d₁₄ was (-2.7 ± 0.1) pmV⁻¹. This compares well with the most recent reported measurements of -2.69 pmV⁻¹. The significance of the measurement is that this represents the first time this coefficient has been measured using the inverse piezoelectric effect. -- For AIN and GaN samples, the present work also represents the first time their piezoelectric coefficients have been measured by interferometry. For GaN, this work presents the first reported measurements of the piezoelectric coefficients, and some of these results have recently been published by the (Muensit and Guy, 1998). The d₃₃ and d₃₁ coefficients for GaN were found to be (3.4 ± 0.1) pmV⁻¹ and (-1.7 ± 0.1) pmV⁻¹ respectively. Since these values were measured on a single crystal wafer and have been corrected for substrate clamping, the values should be a good measure of the true piezoelectric coefficients for bulk GaN. -- For AIN, the d₃₃ and d₃₁ coefficients were found to be (5.1 ± 0.2) pmV⁻¹, and (-2.6 ± 0.1) pmV⁻¹ respectively. Since these figures are measured on a polycrystalline sample it is quite probable that the values for bulk AIN would be somewhat higher. / The piezoelectric measurements indicate that the positive c axis in the nitride films points away from the substrate. The piezoelectric measurements provide a simple means for identifying the positive c axis direction. -- The interferometric technique has also been used to measure the shear piezoelectric coefficient d₁₅ for AIN and GaN. This work represents the first application of this technique to measure this particular coefficient. The d₁₅ coefficients for AIN and GaN were found to be (-3.6 ± 0.1) pmV⁻¹ and (-3.1 ± 0.1) pmV⁻¹ respectively. The value for AIN agrees reasonably well with the only reported value available in the literature of -4.08 pmV⁻¹. The value of this coefficient for GaN has not been measured. -- Some initial investigations into the phenomenon of electrostriction in the compound semiconductors were also performed. It appears that these materials have both a piezoelectric response and a significant electrostrictive response. For the polycrystalline GaN and AIN, the values of the M₃₃ coefficients are of the order of 10⁻¹⁸ m²V⁻². The commercial single crystal GaN and GaAs wafers display an asymmetric response which cannot be explained. / Mode of access: World Wide Web. / Various pagings ill