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- Peter Dowben Publications (12)
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- Axel Enders Publications (2)
- C.J.G.J. Uiterwaal Publications (2)
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- Edward Schmidt Publications (2)
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- Sy-Hwang Liou Publications (2)
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Articles 1 - 30 of 52
Full-Text Articles in Physics
Novel Switching Phenomena In Ferroelectric Langmuir-Blodgett Films, A. Bune, Stephen Ducharme, V.M. Fridkin, L. Blinov, S. Palto, N. Petukhova, S. Yudin
Novel Switching Phenomena In Ferroelectric Langmuir-Blodgett Films, A. Bune, Stephen Ducharme, V.M. Fridkin, L. Blinov, S. Palto, N. Petukhova, S. Yudin
Stephen Ducharme Publications
We have established ferroelectric switching and observed a novel conductance switching phenomenon in ferroelectric polymer films fabricated by the Langmuir–Blodgett technique. The films consist of 10–30 monolayers (ML) of a copolymer of vinylidene fluoride (70%) and trifluoroethylene (30%), exhibiting a first-order ferroelectric phase transition at 70 °C and nearly rectangular ferroelectric and conductance hysteresis at 24 °C. Ferroelectric switching is accompanied by switching of the conductance by three orders of magnitude. A model describing this switching phenomenon is proposed.
Local Magnetic Properties Of Antiferromagnetic Febr2, J. Pelloth, R.A. Brand, S. Takele, M.M. Pereira De Azevedo, Wolfman Kleemann, Christian Binek, J. Kushauer, D. Bertrand
Local Magnetic Properties Of Antiferromagnetic Febr2, J. Pelloth, R.A. Brand, S. Takele, M.M. Pereira De Azevedo, Wolfman Kleemann, Christian Binek, J. Kushauer, D. Bertrand
Christian Binek Publications
The antiferromagnet FeBr2 has been studied by Mössbauer spectroscopy in external fields both in the metamagnetic region below the multicritical temperature TMCP and in the second-order transition region above. The local magnetization shows that the metamagnetic transition occurs by spin flips, as in simple models. However, in the second-order transition region, the local magnetization of the sublattice oriented antiparallel to the external field varies continuously but remains parallel to the c axis. This can only be understood if the external magnetic field induces strong transversal spin precession of the moments on the antiparallel sublattice. This shows that the …
Forming B1-XCX Semiconductor Devices By Chemical Vapor Deposition, Peter A. Dowben
Forming B1-XCX Semiconductor Devices By Chemical Vapor Deposition, Peter A. Dowben
Peter Dowben Publications
Active semiconductor devices including heterojunction diodes and thin film transistors are formed by PECVD deposition of a boron carbide thin film on an N-type substrate. The boron to carbon ratio of the deposited material is controlled so that the film has a suitable band gap energy. Boron carbides such as B4.7C, B7.2C and B19C have suitable band gap energies between 0.8 and 1.7 eV. The stoichiometry of the film can be selected by varying the partial pressure of precursor gases, such as nido pentaborane and methane. The precursor gas or gases are energized, e.g., …
Tailoring Of The Magnetic Properties Of Smco5:Nb0.33Cr0.67 Nanocomposites Using Mechanical Alloying, Richard L. Schalek, Diandra Leslie-Pelecky, John Knight, David J. Sellmyer, Steven C. Axtell
Tailoring Of The Magnetic Properties Of Smco5:Nb0.33Cr0.67 Nanocomposites Using Mechanical Alloying, Richard L. Schalek, Diandra Leslie-Pelecky, John Knight, David J. Sellmyer, Steven C. Axtell
David Sellmyer Publications
Nanocomposite structures composed of ferromagnetic particles dispersed in a matrix are systems in which the magnetic properties can be tailored by varying the size and spacing of the ferromagnetic particles. Nanocomposites of SmCo5 in a non-magnetic Nb0.33Cr0.67 matrix exhibit a wide variety of magnetic properties. SmCo5 powder is premilled prior to mechanical alloying. The premilliing results in a maximum coercivity of 16 kOe after 2 hours of milling, and an enhanced remanence ratio. Both features may be due to exchange anisotropy and/or exchange coupling between hard and soft ferromagnetic phases. The nanocomposite samples show that, …
Magnetic Switching Volumes Of Cosm Thin Films For High Density Longitudinal Recording, E.W. Singleton, Z.S. Shan, Y.S. Jeong, David J. Sellmyer
Magnetic Switching Volumes Of Cosm Thin Films For High Density Longitudinal Recording, E.W. Singleton, Z.S. Shan, Y.S. Jeong, David J. Sellmyer
David Sellmyer Publications
For a high density recording media, the magnetic switching volume is of great importance when considering media noise and thermal stability. CoSm//Cr films have been prepad and the influence of the Cr underlayer thickness and of the magnetic layer preparation conditions on the magnetic switching volume have been investigated through magnetic viscosity and remnance curve measurements. The measured switching volumes ranged from 3.0 to 15.2x10-18 cm3, and implications regarding noise and thermal stability are discussed.
Spin Polarization Of The Conduction Bands Of Gd(0001)*, Dongqi Li, J. Pearson, S.D. Bader, D. N. Mcilroy, C. Waldfried, Peter A. Dowben
Spin Polarization Of The Conduction Bands Of Gd(0001)*, Dongqi Li, J. Pearson, S.D. Bader, D. N. Mcilroy, C. Waldfried, Peter A. Dowben
Peter Dowben Publications
Angle- and spin-resolved photoemission was utilized to investigate the 5d bulk bands and the surface state of Gd(0001) in the temperature range of 130 - 350 K. The bulk bands at 1-2 eV below the Fermi energy EF show Stoner-like behavior, while the temperature dependence of the surface state near EF indicates spin-mixing behavior due to fluctuating local 5d moments. The secondary electron spectra of the Gd surfaces both before and after initial oxygen adsorption show a polarization dip at low kinetic energies due to the extra scattering channel for minority electrons via the unoccupied 4ƒ level. The …
Magnetic Properties And Structure Of Fe/Pt Thin Films, C.P. Luo, David J. Sellmyer
Magnetic Properties And Structure Of Fe/Pt Thin Films, C.P. Luo, David J. Sellmyer
David Sellmyer Publications
The structural transfqmation from fcc to fct and relevant magnetic properties of initially multilayered Fe/Pt films were studied. When the as-deposited FePt films were annealed at the temperature of 300°C and up, the fct-phase was formed. Rather square hysteresis loops and large coercivities were measured from the annealed films. The films annealed at 300°C retain a layered structure.
High Resolution Electron Microscopy And Nano-Probe Study Of Cosm/Cr Films, Yi Liu, David J. Sellmyer, B. W. Robertson, Z.S. Shan, Sy_Hwang Liou
High Resolution Electron Microscopy And Nano-Probe Study Of Cosm/Cr Films, Yi Liu, David J. Sellmyer, B. W. Robertson, Z.S. Shan, Sy_Hwang Liou
Sy-Hwang Liou Publications
The crystal structure of the crystallites in CoSm thin films deposited on Cr underlayer was studied by nanodiffraction and high resolution electron microscopy (HREM). It was found that the crystallites have a closed-packed structure. Some nanodiffraction patterns taken from different crystallites using a two nanometer probe can be indexed by two layer stacking AB (HCP structure), three layer stacking ABC (FCC structure), and four layer stacking ABAC (double hexagonal structure), suggesting that a particular local stacking mode could exist. [112-0] HREM images confirmed that stacking sequence changes within one crystallite. In local regions, random stacking, and unit cells …
Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer
Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer
Department of Physics and Astronomy: Faculty Publications
Magnetic and magneto-optical properties of MnxCuBi ( x = 0.75 - 3.5) thin films are presented. With increasing Mn concentration x, the perpendicular anisotropy constant (Ku the remanence squareness (S = Mr/Ms) and the coercivity (Hc)the perpendicular hysteresis loop increase. Remanence squareness as high as 0.95 has been obtained. Kerr rotation (θk) and ellipticity (ηk) spectra from all samples measured from substrate side are similar, with θk exhibiting a broad peak in the blue wavelength region with maximum Kerr rotation up to 0.7 degrees.
Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films†, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer
Magnetic And Magneto-Optical Properties Of MnXCubi ( X =0.75 - 3.5 ) Films†, Jian Chen, K. Wierman, Roger D. Kirby, David J. Sellmyer
Department of Physics and Astronomy: Faculty Publications
Abstract - Magnetic and magneto-optical properties of MnxCuBi ( x = 0.75 - 3.5) thin films are presented. With increasing Mn concentration x, the perpendicular anisotropy constant (Ku), the remanence squareness (S = Mr/Ms) and the coercivity (Hc ), of the perpendicular hysteresis loop increase. Remanence squareness as high as 0.95 has been obtained. Kerr rotation (Өk) and ellipticity (ηk) spectra from all samples measured from substrate side are similar, with Өk exhibiting a broad peak in the blue wavelength region with maximum Kerr rotation up …
Correlation Between Screening And Electron Effective Mass Across The Nonmetal-Metal Transition In Ultrathin Films, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben
Correlation Between Screening And Electron Effective Mass Across The Nonmetal-Metal Transition In Ultrathin Films, Jiandi Zhang, D.N. Mcilroy, Peter A. Dowben
Peter Dowben Publications
Angle-resolved photoemission and resonant photoemission have been used to determine the relative changes of the electron effective mass and the screening parameter across the nonmetal to metal transition in the magnesium thin films on Mo(112). Both the screening length and the electron effective mass exhibit a gradual change with Mg coverage in the transition range between half and one monolayer. The relationship of these two different measures of metallicity is in surprisingly good agreement with the relationship predicted by theory for the Mott-Hubbard transition. Our results indicate the importance of electron-electron correlation within the overlayer.
Magnetic-Field-Induced Griffiths Phase Versus Random-Field Criticality And Domain Wall Susceptibility Of Fe0.47zn0.53f2, Christian Binek, S. Kuttler, Wolfgang Kleemann
Magnetic-Field-Induced Griffiths Phase Versus Random-Field Criticality And Domain Wall Susceptibility Of Fe0.47zn0.53f2, Christian Binek, S. Kuttler, Wolfgang Kleemann
Christian Binek Publications
The well-known peak of the parallel ac susceptibility arising below TN in Fe0.47Zn0.53F2 splits into a narrow critical peak at Tc (H) and a broad field-induced Griffiths phase shoulder peaking at Tp>Tc(H) in magnetic fields H≳1.6 MA /m. Random-field (RF) criticality with α̃≈0 and subsequent rounding due to RF trapping of thermal fluctuations are observed upon zero-field cooling as T→Tc-(H). The frozen domain state obtained after rapid field cooling reveals excess susceptibility Δχw′∝H2.6, owing to rough walls with thermally activated stiffness.
Control Of Bright Picosecond X-Ray Emission From Intense Subpicosecond Laser-Plasma Interactions, J. Workman, Anatoly Maksimchuk, X. Liu, U. Ellenberger, J.S. Coe, C.-Y. Chien, Donald P. Umstadter
Control Of Bright Picosecond X-Ray Emission From Intense Subpicosecond Laser-Plasma Interactions, J. Workman, Anatoly Maksimchuk, X. Liu, U. Ellenberger, J.S. Coe, C.-Y. Chien, Donald P. Umstadter
Donald Umstadter Publications
Using temporally and spectrally resolved diagnostics, we show that the pulse duration of laser-produced soft x rays emitted from solid targets can be controlled, permitting a reduction to as short as a few picoseconds. To enable this control, only a single parameter must be adjusted, namely, the intensity of the high-contrast ultrashort laser pulse (400 fs). These results are found to be in qualitative agreement with a simple model of radiation from a collisionally dominated atomic system.
Thindown In Biological 1-Hit Detectors: E. Coli B/R And Bs-1*, Zhang Chunxiang, Robert Katz
Thindown In Biological 1-Hit Detectors: E. Coli B/R And Bs-1*, Zhang Chunxiang, Robert Katz
Robert Katz Publications
According to the theory of Butts and Katz and the new radial dose distribution of Zhang et al., we have calculated inactivation cross sections for the heavy ion bombardment of E. Coli B/r and Bs-1 which w& in agreement with the measurements of Scliafer et made with ions from O to U at energies from 1.5 to 19.5 MeV/u. The data display "thindown", and the decrease in cross section with an increase in stopping power is accompanied by a decrease in energy of a bombarding ion. Following an earlier analysis of heavy ion bombardments of these E. Coli mutants with …
A Novel Design For A Small Retractable Cylindrical Mirror Analyzer, D.N. Mcilroy, Peter A. Dowben, A. Knop, E. Ruhl
A Novel Design For A Small Retractable Cylindrical Mirror Analyzer, D.N. Mcilroy, Peter A. Dowben, A. Knop, E. Ruhl
Peter Dowben Publications
In this paper we will review the performance of a “miniature” single pass cylindrical mirror analyzer (CMA) which we have used successfully in a variety of experiments. The underlying premise behind this CMA design was to minimize spatial requirements while maintaining an acceptable level of instrumental resolution. While we are presenting the results of a single pass cylindrical mirror analyzer, improvements on the present design, such as going to a double pass design, will undoubtedly improve the instrumental resolution.
A Novel Design For A Small Retractable Cylindrical Mirror Analyzer, D.N. Mcilroy, Peter A. Dowben, A. Knop, E. Ruhl
A Novel Design For A Small Retractable Cylindrical Mirror Analyzer, D.N. Mcilroy, Peter A. Dowben, A. Knop, E. Ruhl
Peter Dowben Publications
In this paper we will review the performance of a “miniature” single pass cylindrical mirror analyzer (CMA) which we have used successfully in a variety of experiments. The underlying premise behind this CMA design was to minimize spatial requirements while maintaining an acceptable level of instrumental resolution. While we are presenting the results of a single pass cylindrical mirror analyzer, improvements on the present design, such as going to a double pass design, will undoubtedly improve the instrumental resolution.
Stress Evolution During The Growth Of Ultrathin Layers Of Iron And Iron Silicide On Si(111), D. Sander, Axel Enders, J. Kirschner
Stress Evolution During The Growth Of Ultrathin Layers Of Iron And Iron Silicide On Si(111), D. Sander, Axel Enders, J. Kirschner
Axel Enders Publications
Using a simple optical deflection technique, we measured continuously the mechanical stress during the growth of Fe films of 0.1–1.5 nm thickness on Si(111) in ultrahigh vacuum (UHV). The stress versus coverage dependence is discussed in view of the different growth modes during the various stages of Fe deposition. The deposition of up to 0.3 nm Fe induces a compressive stress of -1 N/m. We assign this stress to the formation of a reactive Fe–Si interface layer with a silicide-like structure. Subsequent Fe deposition at 300 K leads to a small tensile stress of 0.7 N/m, whereas the deposition at …
Mercury Surface-Plasmon Dispersion: Experiment And Theory, Bong-Ok Kim, Geunseop Lee, E. Ward Plummer, Peter A. Dowben, A. Liebsch
Mercury Surface-Plasmon Dispersion: Experiment And Theory, Bong-Ok Kim, Geunseop Lee, E. Ward Plummer, Peter A. Dowben, A. Liebsch
Peter Dowben Publications
Momentum-resolved inelastic electron spectroscopy has been utilized to measure the surface-plasmon dispersion and damping for thick Hg films grown onto a Cu(100) substrate. Hg has been investigated since it offers an opportunity to examine the effects of the crystal potential on the surface-plasmon dispersion, and to correlate the measurements on a surface with those for collective excitations in clusters. The effects of the electronic band structure of Hg can be seen in the energy and width of the surface plasmon as a function of momentum transfer q∥. Dynamical response calculations were performed for a semi-infinite electron gas where several important …
Magnetic Properties Of Nanostructured Cosm/Feco Films, I.A. Al-Omari, David J. Sellmyer
Magnetic Properties Of Nanostructured Cosm/Feco Films, I.A. Al-Omari, David J. Sellmyer
David Sellmyer Publications
Co80Sm29/Fe65Co35 bilayer and multilayer films with Cr underlayers and overlayers have been fabricated and studied. All the samples prepared have in-plane anisotropy and the hysteresis loops were simple single loops for tFeCo≤300 Å indicating that the two phases are strongly exchange coupled. The magnetization of these samples is found to increase with increasing FeCo layer thickness for a fixed CoSm layer thickness. The coercivity, anisotropy constant, and anisotropy field for films with fixed CoSm layer thickness were found to decrease with increasing FeCo layer thickness. The magnetization squareness values of the …
Method And Apparatus For Generating Laser Plasma X-Rays, Donald P. Umstadter, Jonathan Workman, Anatoly Maksimchuk, Xinbing Liu
Method And Apparatus For Generating Laser Plasma X-Rays, Donald P. Umstadter, Jonathan Workman, Anatoly Maksimchuk, Xinbing Liu
Donald Umstadter Publications
The present information provides a system and an apparatus to produce x-rays from plasmas by focusing an intense, short duration optical pulse from a laser onto a target. The concentrated energy contained in the focused laser beam ionizes the target material, raising it to a temperature at which ions are produced in a chain reaction ionization, and x-rays are emitted when ions become de-excited (their electrons change energy level) or free electrons recombine with the ions in the plasma. The method comprises controlling pulse time duration of x-rays emitted from a plasma-forming target generating a beam of one or more …
A Photometric Study Of V508 Cygni, S.N. Goderya, Kam-Ching Leung, Edward G. Schmidt
A Photometric Study Of V508 Cygni, S.N. Goderya, Kam-Ching Leung, Edward G. Schmidt
Edward Schmidt Publications
The Behlen observatory 0.76 m telescope CCD photometer has been used to obtain nearly 700 observations of the short period eclipsing binary V508 Cyg. These observations were done using V and R bandpass filters on 9 nights in 1992. Previously published light elements and the present eight determinations of eclipse timings are used to determine a new epoch and a more accurate orbital period of 0.7796587 days. The photometric observations and solutions which have been obtained with the 1993 version of the Wilson- Devinney model show that V508 Cyg is a W UMa type contact binary system. Analyses give two …
Low Dose, Robert Katz, Francis A. Cucinotta
Low Dose, Robert Katz, Francis A. Cucinotta
Robert Katz Publications
Low doses of radiation are frequently inferred to mean doses of the order of 10-100 mGy, regardless of the end point or the nature of the irradiation, as if the energy were deposited uniformly through all targets. Yet, the fluence in a charged particle beam at which there is an average of 1 charged particle transit per target leaves 37% of the targets untouched. At an average of 3 transits per target, 5% of the targets experience no particle transits. Only at an average of 5 transits per target do 99% of the targets achieve one or more transits. One …
Nanoscale Visualization And Control Of Ferroelectric Domains By Atomic Force Microscopy, Oleg Kolosov, Alexei Gruverman, Jun Hatano, Koichiro Takahashi, Hiroshi Tokumoto
Nanoscale Visualization And Control Of Ferroelectric Domains By Atomic Force Microscopy, Oleg Kolosov, Alexei Gruverman, Jun Hatano, Koichiro Takahashi, Hiroshi Tokumoto
Alexei Gruverman Publications
The nanoscale visualization and control of domain structure with atomic force microscopy (AFM) in the ferroelectric crystal guanidinium aluminum sulfate hexahydrate is reported. The origin of the domain contrast in the topographic of AFM images is explained by the piezoelectric deformation of the crystal surface in the internal electric field. The domain structure was modified by applying a voltage to the conductive AFM tip. The dynamics of domain growth has been directly observed for the first time with a resolution of 10 nm.
State-Selected Ion-Molecule Reactions: Statistical Calculations With Constraints, Cornelis J. Uiterwaal, J. Van Eck, A. Niehaus
State-Selected Ion-Molecule Reactions: Statistical Calculations With Constraints, Cornelis J. Uiterwaal, J. Van Eck, A. Niehaus
C.J.G.J. Uiterwaal Publications
For the two reactive systems, NH3+(Eint)+N H3→NH4++NH2 and H2+ (Eint)+H2→H3+ + H, for which the relative cross sections were measured earlier in our group for Ec.m.≈40 meV we calculated the relative cross section as a function of internal energy using the statistical Rice– Ramsperger–Kassel–Marcus (RRKM) theory that implicitly conserves total energy and total angular momentum. We found satisfactory agreement between theory and experiment by imposing rather mild constraints upon the loose transition state configuration. These constraints involve …
Spin-Polarized Photoemission Studies Of The Exchange Splitting Of The Gd 5d Electrons Near The Curie Temperature, Dongqi Li, J. Pearson, S.D. Bader, D.N. Mcilroy, C. Waldfried, Peter A. Dowben
Spin-Polarized Photoemission Studies Of The Exchange Splitting Of The Gd 5d Electrons Near The Curie Temperature, Dongqi Li, J. Pearson, S.D. Bader, D.N. Mcilroy, C. Waldfried, Peter A. Dowben
Peter Dowben Publications
Spin-polarized photoemission was employed to investigate the temperature dependence of the exchange splitting of Gd(0001) for both the surface state near the Fermi level EF and the 5d bulk bands. The bulk bands at 1–2 eV below E F show Stoner-like behavior where two peaks with opposite spin polarization shift toward each other as the temperature increases. In contrast, the temperature dependence of the surface state indicates spin-mixing behavior due to fluctuating local moments. These differences are attributed to the degree of itinerancy of the 5d electrons in the two cases.
Disorder And Noncollinear Magnetism In Permanent-Magnet Materials With The Thmn12 Structure, R. Lorenz, J. Hafner, Sitaram Jaswal, David J. Sellmyer
Disorder And Noncollinear Magnetism In Permanent-Magnet Materials With The Thmn12 Structure, R. Lorenz, J. Hafner, Sitaram Jaswal, David J. Sellmyer
David Sellmyer Publications
We report calculations of the noncollinear magnetic structures of YFe12-xMox permanent-magnet materials, using a novel variant of a spin-polarized tight-binding–linear-muffin-tin-orbital technique allowing for local spin-quantization axes on each site and considering spin-orbit coupling. The ternary YFe12-xMox compounds crystallize in the tetragonal ThMn12 structure which can be stabilized only by the partial substitution of Fe by an early transition metal like Mo. We show that the substitutional disorder leads to canted spin structures at low Mo content ( x~1) and to spin-glass-like behavior at higher Mo content (x~3).
Resonant Photoemission Studies Of The Thickness Dependence Of The Unoccupied Gd 5D Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion
Resonant Photoemission Studies Of The 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 absorption 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 pp-polarized light excites only to the unoccupied dz2 …
Scanning Tunneling Microscopy Study Of Intermediates In The Dissociative Adsorption Of Closo-1,2-Dicarbadodecaborane On Si(111), J.M. Carpinelli, E. Ward Plummer, Dongjin Byun, Peter A. Dowben
Scanning Tunneling Microscopy Study Of Intermediates In The Dissociative Adsorption Of Closo-1,2-Dicarbadodecaborane On Si(111), J.M. Carpinelli, E. Ward Plummer, Dongjin Byun, Peter A. Dowben
Peter Dowben Publications
Closo-1,2-dicarbadodecaborane (C2B10H12) is a source compound found to be suitable for the deposition of a high resistivity form of boron-carbide (B5C), and the fabrication of boron-rich semiconductor devices. A scanning tunneling microscope (STM) was used to image these molecular icosahedra on Si(111)-(7x7). Molecular decomposition (tip induced and otherwise! produced a boron-carbide/silicon interface with pronounced heterojunction electronic characteristics. In STM, this interface is characterized by a disordering of the Si(111)-(7x7) reconstruction. We suggest, based on Auger electron spectroscopy data and low-energy electron diffraction observations, that boron atoms from the dissociated source molecules …
Resonant Photoemission Studies Of The Thickness Dependence Of The Unoccupied Gd 5D Bands, Peter A. Dowben, Dongqi Li, Jiandi Zhang, M. Onellion
Resonant Photoemission Studies Of The 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 absorption 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 …
Scanning Tunneling Microscopy Study Of Intermediates In The Dissociative Adsorption Of Closo-1,2-Dicarbadodecaborane On Si(111), J.M. Carpinelli, E.W. Plummer, Dongjin Byun, Peter A. Dowben
Scanning Tunneling Microscopy Study Of Intermediates In The Dissociative Adsorption Of Closo-1,2-Dicarbadodecaborane On Si(111), J.M. Carpinelli, E.W. Plummer, Dongjin Byun, Peter A. Dowben
Peter Dowben Publications
Closo-1,2-dicarbadodecaborane (C2B10H12) is a source compound found to be suitable for the deposition of a high resistivity form of boron-carbide (B5C), and the fabrication of boron-rich semiconductor devices. A scanning tunneling microscope (STM) was used to image these molecular icosahedra on Si(111)-(7 x 7). Molecular decomposition (tip induced and otherwise) produced a boron-carbide/silicon interface with pronounced heterojunction electronic characteristics. In STM, this interface is characterized by a disordering of the Si(111)-(7 x 7) reconstruction. We suggest, based on Auger electron spectroscopy data and low-energy electron diffraction observations, that boron atoms from the …