Large vacancy clusters, or voids, formed during crystal growth have been reported in Ge. The divacancy is a precursor to such clusters, and is believed to be stable up to 150 or 180 °C. It is also believed to form in Ge irradiated at room temperature where single vacancies are mobile. Density... (Read more)

Detailed studies of mechanisms for hydrogen dissociative adsorption and diffusion on pure and nitrogen-doped (8, 0) carbon nanotubes are carried out using the first-principles density functional theory method. (1) For pure carbon nanotubes, we have identified the energetically most favorable... (Read more)

The optical excitation and thermal ionization energies of oxygen vacancies in m-HfO₂ are calculated using a non-local density functional theory with atomic basis sets and periodic supercell. The thermal ionization energies of negatively charged V^– and... (Read more)

Cathodoluminescence (CL) and photoluminescence (PL) properties are studied on neodymium (Nd)- and dysprosium (Dy)-ion-implanted 4H–SiC. No appreciable CL and PL can be observed for all as-implanted samples. Strong visible CL due to Nd³⁺ and Dy³⁺ is observed only after... (Read more)

Temperature dependent Hall effect (TDH), low temperature photoluminescence (LTPL), secondary ion mass spectrometry (SIMS), optical admittance spectroscopy (OAS), and thermally stimulated current (TSC) measurements have been made on 6H-SiC grown by the physical vapor transport technique... (Read more)

The energy spectrum of the traps and thermal stability of stored charge have been studied by the thermostimulated exoelectron emission method in hydrogenated H and deuterated D oxide-nitride-oxide (ONO) multilayer stacks of silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memories. It is... (Read more)

In this paper, the formation and evolution of defects induced by ion irradiation with 1 MeV Si⁺ ions in Ni₂Si/4H–SiC Schottky diodes were studied and correlated with the electrical properties of the contacts. The current-voltage characteristics of the contacts... (Read more)

First-principles pseudopotential calculations have been performed to investigate intrinsic defects including vacancies, interstitials, antisite defects, as well as Schottky and Frenkel defects in PbFCl crystals. For the isolated vacancies and interstitials, their formation energies are critically... (Read more)

Adsorption of gold atoms and clusters (N=6) on a graphite (0001) surface with defects has been studied using density functional theory. In addition to perfect graphite (0001), three types of surface defects have been considered: a surface vacancy (hole), a pyridinelike defect comprising three... (Read more)

First-principles calculations carried out in 3C- and 4H-SiC show that small metastable carbon clusters can be created in irradiated SiC. The metastable carbon clusters possess occupation levels in the p-type as well as in the n-type 4H-SiC. Depending on the... (Read more)

mplanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine behavior, we calculate the energy of fluorine defect structures in the framework of density functional theory. In addition to identifying the ground-state configuration and diffusion migration barrier of a single fluorine atom in silicon, a set of energetically favorable fluorine defect structures were found (F_nV_m). The decoration of vacancies and dangling silicon bonds by fluorine suggests that fluorine accumulates in vacancy-rich regions, which explains the fluorine redistribution behavior reported experimentally. (Read more)

Dry oxidation kinetics of the Si(001) surface has been investigated using reflectance difference oscillation to resolve atomic-scale phenomena. The activation energy for oxidation has been found to increase as the oxide-Si interface moves in the depth direction, reaching the value for bulk... (Read more)

We report first-principles calculations showing that protons in the vicinity of a Si–SiO₂ interface can behave in two different ways. At an abrupt interface without suboxide bonds (Si–Si bonds at the oxide side of the interface) H⁺ does not become trapped but migrates... (Read more)

Hydrogen is known to passivate Si dangling bonds at the Si-SiO ₂ interface, but the subsequent arrival of H ⁺ at the interface causes depassivation of Si-H bonds. Here we report first-principles density functional calculations, showing that, contrary to conventional... (Read more)

Band-gap states of tungsten in silicon carbide (polytypes 4H, 6H, and 15R) are investigated by deep-level transient spectroscopy (DLTS) and admittance spectroscopy on n-type SiC. Doping with W is done by ion implantation and annealing. To establish a definite chemical identification of band-gap... (Read more)

The spectroscopic properties, structure and interconversions of optically active oxygen-deficiency-related point defects in vitreous silica are reviewed. These defects, the E′-centers (oxygen vacancies with a trapped hole or 3-fold-coordinated silicons), different variants of diamagnetic... (Read more)

It is demonstrated that hydrogen can migrate in silicon as a negatively charged species (H^-). The evidence is the combined observation of a strong electric-field dependence in the rate of removal of PH complexes during bias-temperature stress of hydrogenated Schottky-barrier diodes and... (Read more)