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Full-Text Articles in Physics
Sputter Deposition Of High Resistivity Boron Carbide, Ahmad A. Ahmad, Natale J. Ianno, Seong-Don Hwang, Peter A. Dowben
Sputter Deposition Of High Resistivity Boron Carbide, Ahmad A. Ahmad, Natale J. Ianno, Seong-Don Hwang, Peter A. Dowben
Peter Dowben Publications
We have succeeded in the rf magnetron sputter deposition of high resistivity boron carbide (B1−xCx). This has been accomplished by the sputter depositing the boron carbide from a methane saturated boron carbide target. We show that the composition and optical band gap of the sputter deposited material are functions of the applied rf power. Furthermore, boron carbide/silicon heterojunction diodes fabricated via sputtering compare favorably with those fabricated from borane cage molecule sources using plasma enhanced chemical vapor deposition (PECVD).
The Incorporation Of Nickel And Phosphorus Dopants Into Boron-Carbon Alloy Thin Films, D.N. Mcilroy, S.-D. Hwang, K. Yang, N. Remmes, Peter A. Dowben, A.A. Ahmad, N.J. Ianno, J.Z. Li, H.X. Jiang
The Incorporation Of Nickel And Phosphorus Dopants Into Boron-Carbon Alloy Thin Films, D.N. Mcilroy, S.-D. Hwang, K. Yang, N. Remmes, Peter A. Dowben, A.A. Ahmad, N.J. Ianno, J.Z. Li, H.X. Jiang
Peter Dowben Publications
The structural and electronic properties of nickeland phosphorus-doped boron–carbon (B5C) alloy thin films grown by plasma-enhanced chemical vapor deposition have been examined. The Ni-doped boron–carbon alloys were grown using closo-1,2-dicarbadodecaborane (C2B10H12) as the boron–carbon source compound and nickelocene (Ni(C5H5)2) as the nickel source. The phosphorus-doped alloys were grown using the single-source compound: dimeric chloro-phospha(III)-carborane ([C2B10H10PCl] 2). Nickel doping increased the conductivity, relative to undoped B5C, by six orders of magnitude from 10-9 to 10-3 …
Wave-Vector-Dependent Exchange Splitting In A Local Moment System, C. Waldfried, T. Mcavoy, D. Welipitiya, Takashi Komesu, Peter A. Dowben, Elio Vescovo
Wave-Vector-Dependent Exchange Splitting In A Local Moment System, C. Waldfried, T. Mcavoy, D. Welipitiya, Takashi Komesu, Peter A. Dowben, Elio Vescovo
Peter Dowben Publications
Wave-vector-dependent exchange splitting in a local moment system The electronic structure of strained thin films of Gd has been studied with spin- and angle-resolved photoemission and spin-polarized inverse photoemission. The spin-dependent electronic structure is dominated by a very distinct k dependence of the exchange splitting. The surface magnetic structure is observed to be different from that of the bulk, as indicated by the different electronic structure and a much higher surface Curie temperature. The 4% strain within the Gd films results in an enhanced Curie temperature.
Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy_Hwang Liou, Peter A. Dowben
Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy_Hwang Liou, Peter A. Dowben
Peter Dowben Publications
The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La1-xCaxMnO3 (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance …
Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben
Can Photoemission Accurately Probe The Bulk Electronic Structure Of The Complex Oxides?, Jaewu Choi, C. Waldfried, Sy-Hwang Liou, Peter A. Dowben
Peter Dowben Publications
The surface of the complex oxides, in particular the manganese perovskites, is dominated by a different free enthalpy at the surface. This can be demonstrated by surface segregation after annealing the samples. By comparing relative x-ray photoelectron spectroscopy intensities of the manganese perovskite La1-xCaxMnO3 (x=0.1, 0.35) for different emission angles, the profile of elemental concentration was determined. Analysis shows evidence for pronounced surface segregation of calcium. Our results suggest that there are strong differences between surface and bulk enthalpies without segregation or surface relaxation. This is consistent with the previously observed surface resonance in the …
The Influence Of Enhanced Surface Magnetism On Finite-Size Scaling, C. Waldfried, T. Mcavoy, D. Welipitiya, Peter A. Dowben, Elio Vescovo
The Influence Of Enhanced Surface Magnetism On Finite-Size Scaling, C. Waldfried, T. Mcavoy, D. Welipitiya, Peter A. Dowben, Elio Vescovo
Peter Dowben Publications
The thickness-dependent spin-polarized electronic structure of strained ultrathin and thin films of Gd has been investigated. The surface magnetic structure dominates the magnetic ordering of the ultrathin Gd films. With decreasing thickness some bulk bands exhibit increasingly more "passive" magnetic behavior. These bulk bands resemble a paramagnet over an increasing volume of the bulk Brillouin zone with decreasing film thickness.
Finite Size Scaling In The Thin Film Limit, C. Waldfield, D. Welipitiya, T. Mcavoy, Peter A. Dowben, Elio Vescovo
Finite Size Scaling In The Thin Film Limit, C. Waldfield, D. Welipitiya, T. Mcavoy, Peter A. Dowben, Elio Vescovo
Peter Dowben Publications
The thickness dependent spin-polarized electronic structure of strained thin and ultrathin films of Gd is characterized by a distinct change in the critical exponent λ in the formalism of finite size scaling. The reduced critical exponent in the ultrathin films can be correlated to the increased dominance of the surface magnetic structure and the increasing paramagnetic-like behavior of the bulk. ©1998 American Institute of Physics.
Strain Induced Alteration Of The Gadolinium Surface State, C. Waldfried, D.N. Mcilroy, T. Mcavoy, D. Welipitiya, Peter A. Dowben, Elio Vescovo
Strain Induced Alteration Of The Gadolinium Surface State, C. Waldfried, D.N. Mcilroy, T. Mcavoy, D. Welipitiya, Peter A. Dowben, Elio Vescovo
Peter Dowben Publications
Strain induced alteration of the gadolinium surface state The electronic structure of strained and unstrained Gd(0001) has been studied with photoemission, inverse photoemission, and spin-polarized photoemission. A shift of the occupied majority and unoccupied minority surface states has been observed as a result of the strain, consistent with the phase accumulation model. There is a strain induced shift of the minority spin surface state across the Fermi level. ©1998 American Institute of Physics.
The Growth Of Strained Thin Films Of Gadolinium, C. Waldfried, O. Zeybek, T. Bertrams, S.C. Barrett, Peter A. Dowben
The Growth Of Strained Thin Films Of Gadolinium, C. Waldfried, O. Zeybek, T. Bertrams, S.C. Barrett, Peter A. Dowben
Peter Dowben Publications
The growth of strained thin films of gadolinium has been investigated with low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) and compared to the film growth of unstrained gadolinium. Strained thin films of gadolinium are distinct from the unstrained films by a substrate induced preferential domain growth direction, which is also reflected in the electronic structure.
The Spin Polarized Band Structure Of Strained Thin Films Of Gadolinium, C. Waldfried, Elio Vescovo, Peter A. Dowben
The Spin Polarized Band Structure Of Strained Thin Films Of Gadolinium, C. Waldfried, Elio Vescovo, Peter A. Dowben
Peter Dowben Publications
The magnetic properties of strained thin films of gadolinium are characterized by a wave vector and thickness dependence of the exchange splitting. The spin-resolved band structure has been mapped by spin polarized photoemission, and provides considerable insight into the relationship between magnetism of local moment systems, and band structure.
Changes In Metallicity And Electronic Structure Across The Surface Ferroelectric Transition Of Ultrathin Crystalline Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymers, Jaewu Choi, Peter A. Dowben, Shawn Pebley, A.V. Bune, Stephen Ducharme, V.M. Fridkin, S.P. Palto, N. Petukhova
Changes In Metallicity And Electronic Structure Across The Surface Ferroelectric Transition Of Ultrathin Crystalline Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymers, Jaewu Choi, Peter A. Dowben, Shawn Pebley, A.V. Bune, Stephen Ducharme, V.M. Fridkin, S.P. Palto, N. Petukhova
Peter Dowben Publications
The surface ferroelectric-paraelectric phase transition in crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%), at about 20 °C, is accompanied by a dramatic change in both the electronic structure and metallicity. The temperature-dependent changes in the electronic structure occur primarily in the conduction band. This P(VDF-TrFE 70:30) material is observed to resemble an n-type semiconductor, and the change in electronic structure at the surface ferroelectric transition resembles a semiconductor-to-semimetal transition.