The energetics of H2 interacting with the Si(100) surface is studied by means of ab initio total energy calculations within the framework of density functional theory. We find a direct desorption pathway from the mono-hydride phase which is compatible with experimental activation energies and demonstrate the importance of substrate relaxation for this process. Both the transition state configur...

We study the kinetic pathways for the isotropic-to-nematic transition in a fluid of colloidal hard rods. In order to follow the formation of the nematic phase, we develop a new cluster criterion that distinguishes nematic clusters from the isotropic phase. Applying this criterion in Monte Carlo simulations, we find spinodal decomposition as well as nucleation and growth depending on the supersa...

Solution-processed organic ferroelectric resistive switches could become the long-missing non-volatile memory elements in organic electronic devices. To this end, data retention in these devices should be characterized, understood and controlled. First, it is shown that the measurement protocol can strongly affect the ‘apparent’ retention time and a suitable protocol is identified. Second, it i...

We report the fabrication of low-leakage rectifying Pt and Au Schottky diodes and Au-gated metal-semiconductor field effect transistors (MESFETs) on n-type SrTiO3 thin films grown by hybrid molecular beam epitaxy. In agreement with previous studies, we find that compared to Pt, Au provides a higher Schottky barrier height with SrTiO3. As a result of the large dielectric constant of SrTiO3 and t...

Reactions occurring at a carbon atom through the Walden inversion mechanism are one of the most important and useful classes of reactions in chemistry. Here we report an accurate theoretical study of the simplest reaction of that type: the H+CH4 substitution reaction and its isotope analogues. It is found that the reaction threshold versus collision energy is considerably higher than the barrie...

In this paper, we propose a new and complete mechanism for dual fluorescence of methyl salicylate (MS) under different conditions using a combined experimental (i.e., steady-state absorption and emission spectra and time-resolved fluorescence spectra) and theoretical (i.e., time-dependent density function theory) study. First, our theoretical study indicates that the barrier height for excited ...

The current transport mechanism through porous silicon ~PS! films fabricated from 8 to 12 V cm p-type silicon (p-Si) substrates has been investigated using current–voltage I(V) measurements on metal/PS/p-Si/metal devices in the temperature range of 77–300 K. The characteristics for all devices show a rectifying behavior with ideality factor very close to unity. A value of 0.7 eV is obtained for...

Diodes made by (indirectly) evaporating Au on a monolayer of molecules that are adsorbed chemically onto GaAs, via either disulfide or dicarboxylate groups, show roughly linear but opposite dependence of their effective barrier height on the dipole moment of the molecules. We explain this by Au-molecule (electrical) interactions not only with the exposed end groups of the molecule but also with...

Magnetite thin films with a preferred ~111! orientation have been deposited by reactive dc magnetron sputtering from a pure Fe target onto ~100! GaAs substrates at 400 °C. The films show a clear Verwey transition in both the magnetization and sheet resistance as functions of temperature. For films deposited onto semiconducting n-type GaAs substrates, we have obtained asymmetric current–voltage ...

Proton irradiation effects on strained Si 1.XGeX/Si heterostructures have been studied. For the experiment, p+-Sil -xGex/p--Si heterojunction diodes were fabricated by molecular beam epitax y (MBE) growth of strained p+boron doped SiGe layers on p -Si(100) substrates. Due to the valence band discontinuity between SiGe and Si layers, and degenerate doping in the SiGe layer, the characteristics o...