Showing papers on "Photoemission spectroscopy published in 1982"
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01 Jul 1982
TL;DR: In this article, the interaction of Electromagnetic Radiation with Atoms and Molecules is discussed. But the authors focus on the interaction between the electromagnetic radiation with atoms and molecules.
Abstract: Quantization of Energy. Interaction of Electromagnetic Radiation with Atoms and Molecules. General Experimental Methods. Rotational Spectroscopy. Vibrational Spectroscopy. Electronic Spectroscopy. Photoelectron Spectroscopy. Lasers and Laser Spectroscopy. Appendix. References. Indexes.
263 citations
TL;DR: In this paper, the Schottky barrier formation has been characterized for Si(100) surface, both with and without surface oxides present, and the results were carried out in ultra-high vacuum, while observing electronic and chemical changes with ultraviolet photoemission spectroscopy and Auger electron spectrograph.
Abstract: Silicide and Schottky barrier formation has been characterized for Ti deposited on the Si(100) surface, both with and without surface oxides present. Reactions were carried out in ultrahigh vacuum, while observing electronic and chemical changes with ultraviolet photoemission spectroscopy and Auger electron spectroscopy. Ti deposited on Si shows a sharp interface, no change in Fermi level position, and no silicide formation until heated to 400–500 °C. Ti deposited on thin oxides (<20 A) frees silicon at the interface and reacts through the oxide to form a silicide when heated to 400–500 °C. Ti deposited on thick thermal oxides also frees Si, but no further reaction occurs until heated to 700–900 °C, at which point TiOx forms near the surface. This differing behavior of thin and thick oxides is shown to be consistent with bulk thermodynamic data.
115 citations
TL;DR: A review of current work on photoelectron emission spectroscopy of aqueous solutions can be found in this article, where theoretical background covers: free energy of emission, threshold energy for emission, reorganization free energy.
Abstract: : Review of current work on photoelectron emission spectroscopy of aqueous solutions. Theoretical background covers: free energy of emission, threshold energy for emission, reorganization free energy. Applications include: water and hydroxide ion, anions, cations, weak acids and bases and their ions. (Author)
97 citations
TL;DR: In this article, the HeI photoelectron spectrum of the gas-phase water dimer produced in a supersonic nozzle beam was measured below 13.5 eV and the first and second vertical ionization energies are 12.1 and 13.2 ± 0.2 eV, respectively.
95 citations
TL;DR: In this article, surface core-level shifts measured using photoemission with synchrotron radiation are reviewed for a variety of transition metals (Ta, W, Ir), rare earth metals (Yb, Sm, Gd, YbAl2), noble metals (Au), and semiconductors (Si, Ge, GaAs).
Abstract: Surface core‐level shifts measured using photoemission with synchrotron radiation are reviewed for a variety of transition metals (Ta, W, Ir), rare earth metals (Yb, Sm, Gd, YbAl2), noble metals (Au), and semiconductors (Si, Ge, GaAs). Models of surface shifts are discussed, including the relationships of surface shifts to surface crystallography, reconstruction, valence electron configuration, surface cohesive energy, etc. Applications of surface shifts which are described include surface reconstruction on metals and semiconductors and high‐resolution chemisorption studies.
86 citations
86 citations
TL;DR: In this paper, the interaction of hydrogen with the diamond (111) surface is examined using the new results in photoemission spectroscopy (PES) and photon-stimulated ion desorption (PSID) yield at photon energies near the carbon K edge.
Abstract: The interaction of hydrogen with the diamond (111) surface is examined using our new results in photoemission spectroscopy (PES) and photon‐stimulated ion desorption (PSID) yield at photon energies near the carbon K edge. Also discussed in the light of our new results are previous studies using PES and low energy electron diffraction (LEED). PSID verifies that the mechanically polished 1×1 surface is hydrogen terminated and finds that the reconstructed surface is hydrogen free. Atomic hydrogen is found to be reactive with the reconstructed surface, while molecular hydrogen is relatively inert. Exposure of the reconstructed surface to atomic hydrogen results in chemisorption of hydrogen and removal of the intrinsic surface state emission in and near the band gap region.
82 citations
TL;DR: In this article, the valence and conduction-band discontinuities of InAs-GaAs (100) heterojunctions were determined by means of XPS measurements.
Abstract: The valence‐ and conduction‐band discontinuities have been determined for the InAs–GaAs (100) heterojunction (HJ) by means of XPS measurements. The values are ΔEv = 0.17±0.07 eV and ΔEc = 0.90±0.07 eV, respectively. The InAs‐GaAs HJ has a rather large lattice mismatch (7%) but high quality epitaxial heterojunctions may be grown by molecular beam epitaxy (MBE). We have carried out XPS measurements on MBE grown InAs (100) films and on the InAs‐GaAs (100) HJ by using a recently developed arsenic cap transfer technique which permits XPS measurements on atomically clean and ordered heterojunctions. XPS is used to obtain the In4d and As3d to valence‐band maximum binding‐energy differences for bulk InAs by fitting the experimental XPS valence‐band density of states (VBDOS) to an instrumentally broadened theoretical VBDOS. The values are (EInAsIn4d−EInAsv) = 17.43 ±0.02 eV and (EInAsAs3d−EInAsv) = 40.77±0.02 eV, respectively. The core‐level separation ΔECL between the In4d and Ga3d core levels for a thin InAs–GaA...
82 citations
TL;DR: In this paper, the authors used soft x-ray photoemission spectroscopy (SXPS) to investigate the dependence of Fermi-level pinning on chemical structure at InP-metal interfaces.
Abstract: We have used soft x‐ray photoemission spectroscopy (SXPS) to investigate the dependence of Fermi‐level pinning on chemical structure at InP–metal interfaces. SXPS core level spectra of Al, Ti, Ni, Au, Pd, Ag, and Cu on UHV‐cleaved InP(110) surfaces reveal evidence for semiconductor outdiffusion, metal indiffusion, metal‐anion bonding and metal‐cation alloying. Corresponding Fermi‐level movements indicate a range of pinning positions at significantly different energies within the n‐type InP band gap. These results demonstrate that the Schottky barrier heights depend sensitively on changes in interface chemical bonding and diffusion, which strongly affect the type of electrically active sites and interfacial layers formed.
81 citations
TL;DR: In this article, the He(I) photoelectron spectrum of the N3(X 2H) radical, produced by the rapid gas phase reaction of fluorine atoms with hydrazoic acid, has been recorded.
Abstract: The He(I) photoelectron spectrum of the N3(X 2H) radical, produced by the rapid gas phase reaction of fluorine atoms with hydrazoic acid, has been recorded. Three bands were observed corresponding ...
80 citations
TL;DR: In this article, the singularity index α of the asymmetric C(1s) x-ray photoelectron spectrum (XPS) of vitreous carbon is determined to be 0.19±0.01, independent of the interlayer separation of the graphitic layers.
Abstract: The singularity index α of the asymmetric C(1s) x‐ray photoelectron spectrum (XPS) of vitreous carbon is determined to be 0.19±0.01, independent of the interlayer separation of the graphitic layers. This result is interpreted within the framework of the many‐electron theory; two mechanisms are suggested: (1) the modulation of the two‐dimensional graphite band structures by the random interlayer perturbation, and (2) the excitonic screening. By assigning the value α=0.19 to be characteristic of carbon atoms associated with polynuclear aromatic rings, we show that the fraction of carbon in these rings in coal can be determined by the asymmetry of the C(1s) XPS line.
01 Jan 1982
TL;DR: By selecting various vibronic levels of the intermediate state in resonant two-photon ionization, different vibrational distributions are observed in the resulting photoelectron spectrum as discussed by the authors, including the observation of non-totally symmetric modes.
TL;DR: In this article, the effects of bulklike and surfacelike surroundings on the electronic density of states of a variety of Si-H bonding conformations in hydrogenated amorphous silicon are examined using the cluster Bethe-lattice approach.
Abstract: The effects of bulklike and surfacelike surroundings on the electronic density of states of a variety of Si-H bonding conformations in hydrogenated amorphous silicon are examined using the cluster Bethe-lattice approach. Firstly, we discover that two fundamentally different bonding patterns, with different consequences for the doping mechanism, are consistent with ultraviolet photoemission spectroscopy (UPS) data. These are (1) H atoms bonded in microcrystalline regions and (2) clusters of monohydrides (SiH) in a continuous random network. Our results suggest an experiment in which x-ray photoemission spectroscopy and UPS taken together should distinguish between (1) and (2) and hence contribute toward understanding doping. Secondly, by using the calculated densities of states, the energies of a number of conformations and dehydrogenation reactions are calculated with the use of an empirical bond-strength total-energy scheme. Our results agree with results from annealing experiments. We introduce an improvement in the Bethe-lattice method which permits efficient solution of a second-neighbor tight-binding Hamiltonian, and which is valid for $N\mathrm{th}$-neighbor interactions. We also estimate the Hubbard $U$, Stokes shifts, and electronic states associated with neutral and charged dangling bonds.
TL;DR: In this paper, hydrogen and oxygen-induced chemical shifts have been resolved in Ta and W substrate $4f$ core levels by high-resolution synchrotron-radiation-excited photoemission spectroscopy.
Abstract: Hydrogen- and oxygen-induced chemical shifts have been resolved in Ta and W substrate $4f$ core levels by high-resolution synchrotron-radiation-excited photoemission spectroscopy. The surface levels shift continuously by typically 100 to 200 meV to higher binding energy for increasing hydrogen coverage. This is due to a quenching of surface states in the valence band and a charge transfer from the substrate to the hydrogen atoms. Upon adsorption of oxygen, new core peaks appear at 0.4 to 1.3 eV higher binding energy with respect to the bulk level, indicating the formation of strong chemisorption bonds. Substrate chemical shifts for element $Z$ correlate with chemisorption-induced changes in the heat of surface segregation of the ($Z+1$) constituent in a dilute ${(Z+1)}_{x}{Z}_{1\ensuremath{-}x}$ alloy.
TL;DR: In this article, a clear correlation was found between experimental heterojunction valence-band discontinuities locally measured by photoemission spectroscopy and the LCAO results of the Harrison model.
TL;DR: In this paper, the GaAs(110)-Sb system is studied with Auger Electron Spectroscopy, Low Energy Electron Diffraction, Soft X-Ray Photoemission Spectroscopic and Thermal Desorption and the preliminary LEED analysis favors the later model.
TL;DR: The x-ray induced visible luminescence of SrTiO3 has been studied in the range 15-300°K as mentioned in this paper, where the luminance band at 500 nm was found to be intrinsic and associated with the decay of a relaxed Ti+3O−53 exciton.
Abstract: The x‐ray induced visible luminescence of SrTiO3 has been studied in the range 15–300 °K An apparently single‐emission band at 500 nm has been observed whose efficiency abruptly decreases at ∼30 °K This luminescence band is proposed to be intrinsic and associated with the decay of a relaxed Ti+3O−53 exciton After 15 °K irradiation, a visible absorption spectrum which increases towards the infrared is produced and anneals out at ∼30 °K It is suggested that the absorption is due to electron transition from a Ti+3 center to the conduction band, in accordance with recent ultraviolet photoemission spectroscopy data The thermoluminescence spectrum after 15 °K irradiation has also been determined The first glow peak at 30 °K appears to correlate well with the thermal decay of the irradiation‐induced absorption
TL;DR: In this article, a simple interpretation of the satellite structure observed in the x-ray photoelectron spectrum (XPS) in the C1s and O1s regions, has been obtained.
Abstract: : By employing the X alpha-scattering wave method with a Cu9CO cluster to model the chemisorption of CO on a one-fold site of a Cu(100) surface, a simple interpretation of the satellite structure observed in the x-ray photoelectron spectrum (XPS) in the C1s and O1s regions, has been obtained. The physical model obtained by analyzing the results of the Cu9CO cluster calculations is qualitatively the same as that obtained in a previous study of a CU5CO cluster with the CO in a four-fold site (Solid State Comm. 36, 265 (1980)). The quantitative differences suggest that the present Cu9CO cluster is the better model, however. Experimentally, a three peak structure is observed in both the O1s and C1s hole spectra. The 'first' peak, at lowest binding energy, is followed by a second peak at 2-3 eV higher binding energy and the third peak is at 7-8 eV higher binding energy with respect to the first peak.
TL;DR: In this article, the initial stage of nickel silicide compound formation at Si(100) surfaces was investigated using low-energy electron diffraction and ultraviolet photoemission spectroscopy, and experimental evidence was obtained for the postulated high interface mobility resulting from transforming the bonding of interface Si atoms from covalent to metallic character.
Abstract: The initial stage of nickel silicide compound formation at Si(100) surfaces is investigated using low-energy electron diffraction and ultraviolet photoemission spectroscopy. Experimental evidence is obtained for the postulated high interface mobility resulting from transforming the bonding of interface Si atoms from covalent to metallic character. The bond transformation is induced by nickel atoms occupying tetrahedral interstitial voids of the Si lattice. The observed interstitial Ni $d$-state binding energy suggests a diffusion-layer microstructure which does not favor nickel-atom occupancy of adjacent tetrahedral voids.
TL;DR: In this paper, the X-ray photoelectron spectrum of black phosphorus has been measured for the first time and features in the valence band spectrum were found to be in good agreement with those of the state density recently calculated on the basis of a pseudopotential method.
TL;DR: A survey of the interface chemistry of refractory metals W, Ta, Re, Ir, and Mo during room-temperature Schottky-barrier contact formation to GaAs by using x-ray photoemission spectroscopy (XPS) is reported in this paper.
Abstract: A survey of the interface chemistry of the refractory metals W, Ta, Re, Ir, and Mo during room‐ temperature Schottky‐barrier contact formation to GaAs by using x‐ray photoemission spectroscopy (XPS) is reported. The metals were deposited onto clean n‐type GaAs (100) surfaces within the XPS system by two methods: Evaporation and plasma sputtering. For each metal a distinct interfacial reaction which produced GaAs dissociation and formation of a new metal arsenide is observed. Refractory metals are in general not chemically inert in contact to GaAs and nonabrupt interfaces ∠10 A in width are formed. XPS was also used to correlate interface chemistry with measurement of Schottky‐barrier height during contact formation. XPS measured barrier heights ranged from 0.9–0.7 eV, in the order W, Ir, Mo, Ta, and Re.
TL;DR: Using multichannel scattering theory and configuration-interaction formalism, the authors established general formulas to parametrize the photoemission cross sections in the neighborhood of nonradiatively decaying excited states located near inner-shell ionization thresholds.
Abstract: Photoelectron spectroscopy has allowed us recently to observe both giant resonance enhancement of primary lines and two-electron resonant Auger satellites corresponding to the resonant behavior of photoemission cross sections relative, respectively, to autoionization and Auger decay channels. Using multichannel scattering theory and configuration-interaction formalism, I have established general formulas to parametrize the photoemission cross sections in the neighborhood of nonradiatively decaying excited states located near inner-shell ionization thresholds. Considering both cases of one isolated resonance and $n$-resonant states decaying into $N$ continua, I have shown why the two types of decay (autoionization and Auger) cannot be treated independently and have stressed the importance of coupling autoionization channels with Auger ones to account for the asymmetry profile of Auger partial cross sections and the presence of extra structures due to neighboring resonances in Auger channels. Some examples are discussed to point out that the relative importance of primary and satellite lines may vary strongly with the element and the energy range considered. The determination of the parameter ${\ensuremath{\alpha}}_{n}(\ensuremath{\mu}E)$ typical of a resonance $n$ in each channel $\ensuremath{\mu}$ provides us with many types of information, such as the importance of interchannel coupling, spin-orbit effects, and the existence of shake-up satellites.
TL;DR: In this paper, an assessment of the accuracy with which these positions can be determined by state-of-the-art analyses of experimental measurements, especially elastic low-energy electron diffraction, ion scattering spectroscopy (at both medium and high energies), and photoemission spectrographs, is presented.
TL;DR: In this paper, the vibronic spectra of the 1 A 1→2 A 1 U.V. were analyzed theoretically and the potential curves were obtained by means of ab initio configuration interaction calculations.
Abstract: The vibronic spectra of the 1 A 1→2 A 1 U.V. photoelectron transitions in NH3 and ND3 are analysed theoretically. Optimum geometry and potential curves are obtained by means of ab initio configuration interaction calculations. A one-dimensional approach, using the decoupled planar upper state symmetry coordinates and a Manning type function for the double-minimum potentials, is found to account for frequency shifts, anharmonicity and isotope shifts in the 3a 1 electron ionization. The intensities of the photoelectron spectrum are redetermined through integration of the experimental vibronic bands and are furthermore computed within the Franck-Condon approximation. From calculations of hot band progressions the first adiabatic ionization potentials of NH3 and ND3 could be set to 10·073 and 10·12 eV, respectively.