Solid-state lighting (SSL) technologies, based on semiconductor light emitting devices, have the potential to reduce worldwide electricity consumption by more than 10%, which could significantly reduce U.S. dependence on imported energy and improve energy security. The III-nitride (AlGaInN) materials system forms the foundation for white SSL and could cover a wide spectral range from the deep U...

The copper nitride surface characteristics according to atmospheric pressure plasma (APP) and excimer ultraviolet (EUV) treatment were compared using XPS and AFM. As the result of XPS analysis result, in C1s, the organic material removal effect was greater for EUV treatment than for APP, and the oxygen content was found to be low. In Cu (933 eV) area, the shoulder peak of Cu compound was detect...

RAMACHANDRAN, RAMYA. Investigation of Surface States in Gallium Nitride Devices using a New High Frequency Measurement Technique. (Under the direction of Dr. Douglas W. Barlage). Surface states place a limitation on the high-frequency behavior of Gallium Nitride devices by causing RF dispersion. They are also a source of undesirable 1/f noise. This thesis specifically aims to explore techniques...

The pure elements Ti, Zr, Cr, Nb were selected to produce an TiCrZrNb alloy target and deposited thin films thereof by a reactive high vacuum DC sputtering process. Nitrogen was used as the reactive gas to deposit the nitride thin films. The effect of nitriding on the properties of the TiCrZrNbNx film was tested by changing the nitrogen ratio of the atmosphere. All of the as-deposited TiCrZrNbN...

The aluminum-L,,VV Auger spectra for elemental Al. Al oxide and Al nitride have been measured in an assessment of the utility of Auger spectroscopy in characterizing thin oxidized Al films used in model supported-metal catalyst studies. Clearly distinct spectra were found for the three surface chemical states. The oxide spectrum was shown to be similar to published spectra from bulk, single-cry...

Light and heavy ammonia were decomposed on a clean tungsten foil at 973—1123 K and at PNH3,ND3 ^ 0.2 Torr. The nitrogen uptake and the kinetics of the formation of nitride layers were examined during the course of the reaction. The amount of nitrogen chemisorbed (or the thickness of the nitride layers formed) at higher pressures was found to be appreciably larger from NH3 than from ND3. Additio...

We present experimental results on the observation of a bulk second-order nonlinear susceptibility, derived from both free-space and integrated measurements, in silicon nitride. Phase-matching is achieved through dispersion engineering of the waveguide cross-section, independently revealing multiple components of the nonlinear susceptibility, namely χ(2) yyy = 0.14 ± 0.08 ...

Design of novel materials for efficient solar energy conversion is critical to the development of green energy technology. In this work, we present a first-principles study on the design of nanostructures for solar energy harvesting on the basis of the density functional theory. We show that the indirect band structure of bulk silicon nitride is transferred to direct bandgap in nanowire. We fin...

High-intensity ultrasound exfoliation of a bulk-layered material is an attractive route for large-scale preparation of monolayers. The monolayer slices could potentially be prepared with a high yield (up to 100%) in a few minutes. Exfoliation of natural minerals (such as tungstenite and molybdenite) or bulk synthetic materials (including hexagonal boron nitride (h-BN), hexagonal boron carbon ni...

The influence of reactor wall conditions on the characteristics of high density fluorocarbon plasma etch processes has been studied. Results obtained during the etching of oxide, nitride, and silicon in an inductively coupled plasma source fed with various feedgases, such as CHF3 , C3F6 , and C3F6/H2 , indicate that the reactor wall temperature is an important parameter in the etch process. Ade...