[en] A method is described for promoting oxidation of a silicon or gallium arsenide surface comprising: depositing a ytterbium overlayer on the silicon or gallium arsenide surface prior to the oxidation of the surface

[en] Thermoreflectance studies of bulk samples of V, Nb, Ta, and α-phase TaH/sub x/ are reported and the results interpreted in terms of recent band calculations. The first interband transition is identified as a transition involving the Σ band at E/sub F/. An M₃ critical-point transition is attributed to states at N. Significant changes induced by interstitial hydrogen in solid solution α-TaH/sub x/ are observed and interpreted as due to hybridization and lowering of the N/sup prime/₁ eigenenergy

[en] Synchrotron-radiation photoemission studies of bulk samples of Ni₂Si, NiSi, and NiSi₂ show valence-band emission dominated by Ni 3d-derived features. These d bands shift toward E_F and broaden with increasing Ni concentration and Ni-Ni interaction, falling at -3.2 eV for NiSi₂ and -1.3 eV for Ni₂Si. In each case, the density of states near E_F is very low. These results are interpreted in terms of recent calculations which are shown to forecast correctly the general trends and modifications of the silicide electronic structure. Further, they indicate that the d-band features observed in photoemission reflect d states which are not directly involved in the Ni--Si bonds. Core-level studies show that charge transfer plays a minor role in the chemical bond, but changes in the electronic configuration account for the observed shifts in the Ni 3p binding energy

[en] Zn/ZnSe(001) interfaces fabricated by metal deposition at room temperature onto ZnSe(001) c(2 x 2), 2 x 1, and 1 x 1 surfaces were studied by means of x-ray photoemission spectroscopy and current-voltage and capacitance-voltage measurements. All junctions exhibited an ideal unreactive behavior and an identical Schottky barrier height of 1.85 eV (for p-type conduction). Ab initio pseudopotential calculations for model interface configurations provide a microscopic explanation of the different behavior of Zn/ZnSe junctions as compared to Al/ZnSe and Au/ZnSe junctions

[en] The electronic structures of TiH/sub x/, ZrH/sub x/, and HfH/sub x/ have been studied using photoelectron spectroscopy and synchrotron radiation. Structures in the metal d-derived band within approx.3 eV of the Fermi level E/sub F/ and in the bonding band (approx.3--10 eV below E/sub F/) are compared with theory. In each dihydride, the bonding band center falls at -5.5 eV, at approximately the same energy as previously observed for the dihydrides of Sc and Y. Changes in the emission features near E/sub F/ and at -7 eV have been observed in samples bridging the fcc→fct distortion in ZrH/sub x/, 1.63< or =x< or =1.94. The changes at E/sub F/ demonstrate the Jahn-Teller effect for the electronic states of ZrH/sub x/. The binding energies of the Ti 3p, Zr 4p, Hf 5p, and Hf 4f cores are observed to be greater than in the elemental metals, consistent with charge transfer to the hydrogen site

[en] Synchrotron radiation photoemission studied of ultra-thin Yb diffusion barriers at the interface between Mercury-Cadmium-Telluride semiconductors and Ag overlayers show that the interlayers act as effective diffusion barrier only after thicknesses of 10-15 angstrom are reached. Studied of interlayer morphology by means of photoemission from physisorbed Xe indicate that effective diffusion barriers are consistent with a model in which a continuous Yb-Te reacted layer is covered by an Yb-rich layer with high alloying enthalpy for Hg

[en] We present the first photoemission study of reactions which occur at an alkali-earth--silicon interface. Room-temperature results indicate extensive atomic interdiffusion with substantial ionic bonding. Analysis of the Si 2p core line shape, the Ca 3p core levels, the many-body losses, and the valence bands shows that the first reaction product (1< or =THETA< or =12 A) corresponds to a weakly metallic Ca-Si phase. A second component is Ca-rich but has Si present in two different bonding configurations. Core line-shape analysis facilitates evaluation of interface atomic concentrations and discussions of morphology

[en] Synchrotron radiation photoemission has been used to examine interface reaction of overlayers of V and Ca deposited onto clean surfaces of the bulk hydride YH² and the deuteride NbD_0.75. Changes in the hydrogen-induced bonding bands and the d bands near E_F and variations in the intensities of the substrate core level emission as a function of metal coverage indicate that hydrogen diffuses from the substrate into the overlayer. The results are discussed in terms of the mechanism for hydride formation

[en] Photoelectron spectroscopy using synchrotron radiation and bulk samples cleaved in situ has been used to determine the electronic structure of LaNi₅, LaNi₅Ti/sub 0.1/, LaNi₅Zr/sub 0.1/, and Er₆Mn₂₃. Comparison to analogous measurements of elemental Ni and Mn shows that the occupied states are dominated by the Ni- and Mn-derived d bands. Exposure to oxygen (up to approx.100 L of O₂ at 300 ⁰K) unambiguously results in an oxidized state for Ni and Mn at the suface

[en] Deposition of Mn at room temperature onto atomically clean CdTe(110) surfaces yields atomic interdiffusion for metal coverages <3 angstroms with Mn atoms occupying cation sites within the surface and near-surface layers of the semiconductor, synchrotron radiation photoemission studies with variable photoelectron escape depth indicate the formation of a relatively homogeneous semiconductor surface alloy. The highest Mn concentration observed in the alloy exceeds those obtainable with bulk crystal growth methods