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Hydrogen diffusion in nitride-based Flash memory is examined. The results suggest that the increase in number of programmed electrons leads to a decline in the hydrogen diffusion length.

A systematic and comprehensive computational study of the electronic structure of GaN and InN surfaces in various orientations is reported. All the surface states for polar InN that are located above the conduction-band minimum are found and the source of the intrinsic electron accumulation that is universally observed in InN surfaces is explained.

The x-ray absorption fine structure (XAFS) spectroscopy was used to study the microstructure and electronic structure of epitaxially grown GaN which was subjected to high-dose Si implantation. The analysis of the extended XAFS spectra reveals that implantation with 100 keV Si ions with a fluence equal to 1 * [10.sup.18][cm.sup.-2] renders the material amorphous and promotes the formation of Si-N bonds with a bond length equal to that corresponding in S[i.sub.3][N.sub.4].

Atomic layer deposition (ALD) of tungsten nitride carbide (W[N.sub.x][C.sub.y]) on methyl terminated self-assembled monolayers (SAMs) is studied. SAM substrates give extended transient regimes of different lengths during which the film growth is nonlinear and the ALD films grow in the form of islands and show fractal properties.

X-ray photoelectron spectroscopy is used to characterize the surface chemistry of atomic layer depositions (ALD) of titanium nitride films using alternate doses of TiCl4 and NH3. In terms of the incorporation of contaminants in the grown films, it is found that chlorine is deposited in small quantities on the surface whereas oxygen is detected all throughout the grown films.

The effects of hydrogen (H) and fluorine (F) chemisorption on the work function (PHI) and polarization field of (8,0) boron nitride nanotubes (BNNT) are examined by using periodic density functional theory (DFT). The adsorption of H,F pairs, or H,H pairs, on the tube wall to form a continuous, armchair chain along the tube axis, has produced strong enhancement of the intrinsic polarization field.

The adsorption and subsequent desorption of Ga on (0001) GaN using simultaneous line-of-sight quadrapole mass spectroscopy (QMS) and reflection high-energy electron diffraction (RHEED) is investigated. It is concluded that the experimental results show the complementary nature of the information provided by the RHEED oscillations and the Ga-adlayer coverage measured by QMS.

A technique based on electrostatic force microscopy in which light is used to change the charge states of the local region in a solid is introduced and demonstrated. This technique provides a unique feature that it could be used to probe local electronic transitions of a solid in a submicron scale and it is also applied to study the local electronic structure in InN epifilms.

The growth and characterization of the structural and mechanical properties of tantalum zirconium nitride (TaZrN) films and the subsequent simulation of these properties using an ab initio calculation based on density functional theory (DFT) within the generalized gradient approximation is reported. Thin films of TaZrN are deposited on Si(111) substrates using unbalanced magnetron sputtering.

Generation of surface states and bulk traps in the bottom oxide of silicon-oxide-nitide-oxide-silicon memory cells with thick bottom programed hot-electron-injection-programmed/hot-hole-erased injection is investigated using charge-pumping technique. It is shown that the degradation of the bottom oxide under the hot hole stress is responsible for the shift of the programmed state threshold voltage in retention bake.

The synthesis of two structurally related strontium gallium nitrides containing [GaN(sub 3)](super 6-) anions is described. The results suggest that when both gallium and sodium are present in the melt, early transition metals are incorporated into the nitride products.

An approach for reducing reverse-bias leakage currents in Schottky contacts formed to nitride semiconductor heterostructures grown by molecular-beam epitaxy is described, demonstrated and analysed. By incorporation of a GaN cap layer atop a conventional Al(sub x)Ga(sub 1-x)N/GaN heterostructure field-effect transistor epitaxial layer structure, the direction of the electric field at the metal-semiconductor interface of a Schottky contact is reversed, resulting in a suppression of electron flow into conductive screw dislocations.

The determination of the energy-band offsets between GaN and AIN using the linewidth of an extremely sharp excitonic luminescence transition in Al(sub x)Ga(sub 1-x)N alloy with x=0.18 at 10 K is reported. The observed value of the excitonic linewidth of 17 meV is the smallest and this value is considerably smaller than that calculated using a delocalized exciton model.

The defect accumulation during erbium implantation into gallium nitride (GaN) is investigated as a function of the ion fluence. Based on the principle of channeled implantation the damage build up for random implantation is compared to that for channeled implantation in a fluence range which extends over two orders of magnitude using different ion energies.

The GaN nanowires, having average diameters of ~100 nanometer and lengths up to tens of micrometers and with P-doping were synthesized through a simple thermal evaporation process. The scanning electron microscope and high-resolution field-emission transmission electron microscope analyses revealed that P doping results in a rough surface morphology of GaN nonowires.

The effects of Au nanoparticles on the electronic properties of a GaN surface are investigated using synchrotron radiation photoelectron spectroscopy (SRPES). The results indicate that the effects of self-assembled metal nanoparticles on surface electronic properties of semiconductors should be considered in photoemission measurements for metal/semiconductor systems, especially in the semiconductors with poor conductivity and wide band-gap energy such as p-GaN.

The static and dynamic properties of hot electrons in nitride-based bulk semiconductors through Monte Carlo calculations of velocity-field characteristics, and of the spectra of differential mobility, velocity noise, and noise temperature is investigated. The results confirm that nitrides are promising materials for high-speed, high-power, electronic devices operating at room and higher temperatures.

A novel programming by hot-hole injection nitride electron storage (PHINES) Flash memory technology is developed. Two-bits-per-cell feasibility, low-power and high-speed program/erase, good endurance and data retentivity make it a promising candidate for Flash EEPROM technology in gigabit era applications.

The surface treatment of sapphire is employed by using reactive ion beam (RIB) pretreatment as an alternative process for GaN growth in metal organic chemical vapor deposition (MOCVD) is investigated. Results show that due to RIB treatment, the etching of the sapphire surface and the formation of a very thin, disorders A1ON layer is observed which was partially crystallized during the main growth of GaN.

The energy levels of shallow substitutional donors in GaN are calculated by using effective-mass theory that includes the effects of mass anisotropy, central cell potential correction and the host conduction band edge wave function. Results show the ground state energies and the transition energies from the grown state to the first few excited states.

The effects of structural defects like single atomic vacancies, divacancies and grain boundaries on the mechanical properties of single-crystal GaN nanotubes are investigated. The results have shown that dilute single vacancies and inversion domain grain boundaries in single-crystal GaN nanotubes do not affect the Young modulus of the tubes, but the grain boundary at which the interface is normal to the axis of a nanotube might lower the Young modulus of the single-crystal GaN nanotube.

Zn3N2 polycrystalline films with n(super +)-type conductivity are grown by metalorganic chemical vapor deposition and rf-molecular beam epitaxy with carrier concentration in the range between 10(super19)and ~10(super 20) cm(super-3). Oxygen contamination without an intentional doing is found to be a cause of high electron concentration, leading to larger band-gap energy due to Burstein-Moss shift.

The presence of a threading edge dislocation terminated at the surface of GaN bulk substrates causes a dipole-like strain state ranging over a several micrometer square area. The results are compared with the local electrical potential distortion due to the core charge and attracted defects as analyzed by scanning surface-potential microscopy.

Dendrite-like nanowires of wurtzite GaN by grinding and nitriding the assynthesized GaN powder at 800 degree Celsius with a NH3 flow rate of 150 sccm are synthesized. Since the dimensions of the nanowires in many cases are smaller than the Bohr exciton radius, the bulk nanopowder exhibits a blue shift of the excitonic peak caused by the quantum confinement.

Density-functional theory is used for investigating the structure-property relationship of Cr:AlN by doping up to 5 Cr atoms in large supercells. The results have shown that the segregation of transition metal (TM) dopants is very important in determining the magnetic properties in III-Nitride based diluted magnetic semiconductors (DMS).

An alternative approach is developed for calculating the band gap energy of dilute nitride ternary alloys, [Ga.sub.1-y][In.sub.y][N.sub.x][As.sub.1-x]. The band gap energy for dilute nitride binary alloys, Ga[N.sub.x][As.sub.1-x] and In[N.sub.x][As.sub.1-x] alloys, and a bowing parameter are used to predict the band gap energy [Ga.sub.1-y][In.sub.y][N.sub.x][As.sub.1-x], which is in good agreement with the experimental data for as-grown materials.

Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to study the electronic of nitrogen-related defects in InN(0001). The NEXAFS revealed several defects created by ion-bombardment within the band gap or the conduction band around the nitrogen K-edge of InN and it also provided conclusive experimental evidence for the formation of interstitial nitrogen.

The coulombic effects of electron-hole plasma is studied on the ground and first excited energy levels and carrier wave functions in a GaN/AlGaN quantum well (QW) structure. Findings are applied to explore the potential behavior in the QW electroabsorption under near-band-edge photoexcitation.

The C and N atoms were compared to know the different local environments of these and also to understand the bonding configurations in a series of hydrogenated amorphous carbon nitrides films namely plasma enhanced chemical vapor deposition a-C (sub 1-x) N (sub x): H with 36-42 at percent hydrogen. This is done using a combination of x-ray photoemission spectroscopy (XPS), Infrared (IR), and Raman spectroscopies.