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1994

Peter Dowben Publications

Articles 1 - 8 of 8

Full-Text Articles in Physics

Electron-Beam-Induced Patterned Deposition Of Allylcyclopentadienyl Palladium Using Scanning Tunneling Microscopy, D.S. Saulys, A. Ermakov, E.L. Garfunkel, Peter A. Dowben Dec 1994

Electron-Beam-Induced Patterned Deposition Of Allylcyclopentadienyl Palladium Using Scanning Tunneling Microscopy, D.S. Saulys, A. Ermakov, E.L. Garfunkel, Peter A. Dowben

Peter Dowben Publications

Scanning tunneling microscopy has been used to study the electron-induced decomposition of allylcyclopentadienyl palladium [Pd(η3-C3H5)( η5-C5H5)] and subsequent deposition on a Si(111) surface. Deposition occurs via an electron impact mechanism on either the tip or surface, depending on the bias polarity, and is observed with voltages of 2.75 V. This is close to the predicted condensed phase dissociation energy of 2.3 eV for Pd(η3-C3H5)(η5-C5H5)→Pd+C3H5+C5H5. Metallic ...


Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion Oct 1994

Resonant Photoemission Studies Of Thickness Dependence Of The Unoccupied Gd 5d Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion

Peter Dowben Publications

Ultrathin Gd films have been studied with constant initial-state spectroscopy (CIS) of photoemission utilizing linearly polarized light of synchrotron radiation. The photoemission cross-section of the 5d surface state near EF shows strong photon energy dependence, i.e., sharp peaks in CIS spectra near the Gd 5p1/2 adsorption edge. These peaks originate from resonant photoemission processes involving the occupied 5p and unoccupied 5d levels of the surface atoms. The symmetry of the unoccupied states were determined experimentally by changing the polarization of light, where p-polarized light excites only to the unoccupied dz2 or dxz,yz states ...


Novel Methods For The Fabrication Of Ferromagnetic Nickel And Nickel Boride Thin Films, D. Zych, A. Patwa, S.S. Kher, N.M. Boag, Peter A. Dowben Sep 1994

Novel Methods For The Fabrication Of Ferromagnetic Nickel And Nickel Boride Thin Films, D. Zych, A. Patwa, S.S. Kher, N.M. Boag, Peter A. Dowben

Peter Dowben Publications

Metal-rich nickel boride thin films fabricated from boron-containing precursor compounds by a cluster deposition process are shown to be ferromagnetic. The metal-rich films fabricated by this approach exhibit hysteresis curves similar to those obtained for pure nickel foils. These films are a mixture of pure nickel and the Ni3B nickel boride phases. It is postulated that the hysteresis curves with smaller remnant magnetizations obtained from these films are a consequence of Ni3B inclusions within the films. Other novel organometallic source compounds for nickel chemical-vapor deposition are briefly reviewed. Journal of Applied Physics is copyrighted by The ...


Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben Jul 1994

Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben

Peter Dowben Publications

Using photoelectron spectroscopy, the overlayer electronic structure was observed to he modulated by the Hg growth mode for Hg adsorbed on W(110) at 200 K. The Hg layer-by-layer growth was also characterized by variations in the ratio between the Hg 5d shallow core level and W 4f photoemission intensities. This layer-by-layer growth occurs in spite of surprisingly weak electronic interactions between the adatoms and the substrate.


Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben Jul 1994

Layer-By-Layer Growth Of Hg On W(110), Jiandi Zhang, Dongqi Li, Peter A. Dowben

Peter Dowben Publications

Using photoelectron spectroscopy, the overlayer electronic structure was observed to he modulated by the Hg growth mode for Hg adsorbed on W(110) at 200 K. The Hg layer-by-layer growth was also characterized by variations in the ratio between the Hg 5d shallow core level and W 4f photoemission intensities. This layer-by-layer growth occurs in spite of surprisingly weak electronic interactions between the adatoms and the substrate.


Changes In Electron Localization And Density Of States Near EF Across The Nonmetal-Metal Transition In Mg Overlayers, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben May 1994

Changes In Electron Localization And Density Of States Near EF Across The Nonmetal-Metal Transition In Mg Overlayers, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben

Peter Dowben Publications

A nonmetal-to-metal transition in Mg monolayers on Mo(112) has been indicated by photoemission and resonant photoemission. The dramatic changes of the density of states, the dispersion of bands near EF, and screening are observed across the nonmetal-to-metal transition. The changes of the resonance photon energy and the intensity of Mg 2p→εd excitation, with different coverages, indicate that there exists a correlation between the electronic structure (particularly final-state screening effects) and the overlayer structure. The commensurate-to-incommensurate transition beyond 0.5 monolayer of coverage corresponds to the overlayer nonmetal-to-metal transition, which is due to the hybridization of Mg s ...


Heterojunction Fabrication By Selective Area Chemical Vapor Deposition Induced By Synchrotron Radiation, Dongjin Byun, Seong-Don Hwang, Peter A. Dowben, F. Keith Perkins, F. Filips, N.J. Ianno Apr 1994

Heterojunction Fabrication By Selective Area Chemical Vapor Deposition Induced By Synchrotron Radiation, Dongjin Byun, Seong-Don Hwang, Peter A. Dowben, F. Keith Perkins, F. Filips, N.J. Ianno

Peter Dowben Publications

We have fabricated a B5C, boron-carbide/Si(111) heterojunction diode by the synchrotron radiation-induced decomposition of orthocarborane. This diode can be compared with similar boron-carbide/Si(111) heterojunction diodes fabricated by plasma enhanced chemical vapor deposition. The synchrotron radiation induced chemical vapor deposition is postulated to occur via the decomposition of weakly chemisorbed species and the results suggest that “real-time'' projection lithography (selective area deposition) of boron-carbide devices is possible.


Unoccupied Surface Electronic Structure Of Gd(0001), Dongqi Li, Peter A. Dowben, J.E. Ortega, F.J. Himpsel Mar 1994

Unoccupied Surface Electronic Structure Of Gd(0001), Dongqi Li, Peter A. Dowben, J.E. Ortega, F.J. Himpsel

Peter Dowben Publications

The unoccupied surface electronic structure of Gd(0001) was investigated with high-resolution inverse-photoemission spectroscopy. An empty surface state near EF is observed at Γ¯. Two other surface-sensitive features are also revealed at 1.2 and 3.1 eV above the Fermi level. Hydrogen adsorption on Gd surfaces was used to distinguish the surface-sensitive features from the bulk features. The unoccupied bulk-band critical points are determined to be Γ3- at 1.9 eV and A1 at 0.8 eV.