Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physics
Epitaxial Crn Thin Films With High Thermoelectric Figure Of Merit, Eric L. Thies, Daniel A. Hillsberry, Dmitri A. Tenne
Epitaxial Crn Thin Films With High Thermoelectric Figure Of Merit, Eric L. Thies, Daniel A. Hillsberry, Dmitri A. Tenne
Physics Faculty Publications and Presentations
A large enhancement of the thermoelectric figure of merit is reported in single crystalline films of CrN. The strong reduction of the lattice thermal conductivity in the rock-salt phase of this material is shown to be related to intrinsic lattice instabilities, which is similar to the resonant bonding effect proposed for cubic IV-VI compounds. These results demonstrate that useful ideas from classic thermoelectrics and phase change materials can be extended to transition metal nitrides and oxides.
Adsorption-Controlled Growth Of Bivo4 By Molecular-Beam Epitaxy, D. A. Hillsberry, D. A. Tenne
Adsorption-Controlled Growth Of Bivo4 By Molecular-Beam Epitaxy, D. A. Hillsberry, D. A. Tenne
Physics Faculty Publications and Presentations
Single-phase epitaxial films of the monoclinic polymorph of BiVO4 were synthesized by reactive molecular-beam epitaxy under adsorption-controlled conditions. The BiVO4 films were grown on (001) yttria-stabilized cubic zirconia (YSZ) substrates. Four-circle x-ray diffraction, scanning transmission electron microscopy (STEM), and Raman spectroscopy confirm the epitaxial growth of monoclinic BiVO4 with an atomically abrupt interface and orientation relationship (001)BiVO4 ∥ (001)YSZ with [100]BiVO4 ∥ [100]YSZ. Spectroscopic ellipsometry, STEM electron energy loss spectroscopy (STEM-EELS), and x-ray absorption spectroscopy indicate that the films have a direct band gap of 2.5 ± 0.1 eV.
Nano-Structure Formation Driven By Local Protonation Of Polymer Thin Films, Carsten Maedler, Harald Graaf, Mingdi Yan, Andres H. La Rosa
Nano-Structure Formation Driven By Local Protonation Of Polymer Thin Films, Carsten Maedler, Harald Graaf, Mingdi Yan, Andres H. La Rosa
Physics Faculty Publications and Presentations
We report the creation of nano-structures via Dip Pen Nanolithography by locally exploiting the mechanical response of polymer thin films to an acidic environment. Protonation of cross linked poly(4-vinylpyridine) (P4VP) leads to a swelling of the polymer. We studied this process by using an AFM tip coated with a pH 4 buffer. Protons migrate through a water meniscus between tip and sample into the polymer matrix and interact with the nitrogen of the pyridyl group forming a pyridinium cation. The increase in film thickness, which is due to Coulomb repulsion between the charged centers, was investigated using Atomic Force Microscopy. …
Cryogenic Thin-Film Electron Emitters, Pavel Smejtek, David G. Onn, M. Silver
Cryogenic Thin-Film Electron Emitters, Pavel Smejtek, David G. Onn, M. Silver
Physics Faculty Publications and Presentations
Thin‐film electron emitters are described, which operate below 200°K and below a limiting critical applied voltage (νc) in a stable temperature‐independent regime. Current‐voltage characteristics and normal electron energy distributions are presented. Fabrication and operation criteria are outlined. Comparison with temperature‐dependent emitters is made, and possible conduction mechanisms discussed briefly.
New Thin-Film Tunnel Triode Using Amorphous Semiconductors, Pavel Smejtek, R. F. Shaw, H. Fritzsche, M. Silver, S. Holmberg, S. R. Ovshinsky
New Thin-Film Tunnel Triode Using Amorphous Semiconductors, Pavel Smejtek, R. F. Shaw, H. Fritzsche, M. Silver, S. Holmberg, S. R. Ovshinsky
Physics Faculty Publications and Presentations
A new thin‐film tunnel triode is discussed which uses a p‐type amorphous film to achieve amplification of injected current from a tunnel cathode. It is not only the basis for a new semiconductor device but also suggests a novel method for measuring electrical properties of semiconductors.