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Title: Geochemistry of Interfaces: From Surfaces to Interlayers to Clusters.

Abstract

Abstract not provided.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1375579
Report Number(s):
SAND2016-7771C
646529
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Geosciences Research PI Meeting held August 15-16, 2016 in Gaithersburg, MD.
Country of Publication:
United States
Language:
English

Citation Formats

Greathouse, Jeffery A., Criscenti, Louise, Cygan, Randall T, Ilgen, Anastasia Gennadyevna, and Leung, Kevin. Geochemistry of Interfaces: From Surfaces to Interlayers to Clusters.. United States: N. p., 2016. Web.
Greathouse, Jeffery A., Criscenti, Louise, Cygan, Randall T, Ilgen, Anastasia Gennadyevna, & Leung, Kevin. Geochemistry of Interfaces: From Surfaces to Interlayers to Clusters.. United States.
Greathouse, Jeffery A., Criscenti, Louise, Cygan, Randall T, Ilgen, Anastasia Gennadyevna, and Leung, Kevin. Mon . "Geochemistry of Interfaces: From Surfaces to Interlayers to Clusters.". United States. doi:. https://www.osti.gov/servlets/purl/1375579.
@article{osti_1375579,
title = {Geochemistry of Interfaces: From Surfaces to Interlayers to Clusters.},
author = {Greathouse, Jeffery A. and Criscenti, Louise and Cygan, Randall T and Ilgen, Anastasia Gennadyevna and Leung, Kevin},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Aug 01 00:00:00 EDT 2016},
month = {Mon Aug 01 00:00:00 EDT 2016}
}

Conference:
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  • Recent developments in the use of interlayers to tailor the Schottky barrier height (SBH) at a metal/GaAs interface are discussed. The goal has been to gain control of band bending in the interfacial region by modifying both the interface Fermi energy and the charge density in the depletion region. The approach has been to grow both the interlayer and the metal overlayer under ultrahigh vacuum conditions by molecular beam epitaxy, and then to determine the chemistry of interface formation, structure, and band bending by x-ray photoelectron spectroscopy and diffraction and by low-energy electron diffraction. The interface Fermi energy can bemore » changed from the usual midgap value of 0.7--0.8 eV relative to the band edge by the use of epitaxial transition metal aluminide (TMA) overlayers such as NiAl. The unique chemistry of interface formation between this intermetallic compound and GaAs pins the Fermi level [approximately]0.3--0.4 eV above the valence band maximum, and results in a SBH of [approximately]1 eV. The SBH can be increased to [approximately]1.2 eV by the use of a wide bandgap interlayer such as AlAs. The charge density in the depletion region can be changed by growing an n[sup +]-type group IV interlayer between the TMA overlayer and GaAs substrate. Charge transfer from the interlayer to an n-type substrate reduces the space charge density, and thereby lowers the band bending and, thus, the SBH to [approximately]0.5 eV. The use of these interlayers then produces a range of SBH values of [approximately]0.7 eV, which is a significant improvement over the rather narrow range of 0.1--0.2 eV that results from conventional metallizations. The fundamental interface science that underpins these results is discussed, and an application to complementary digital GaAs circuit design that may significantly reduce gate leakage is given.« less
  • Recent developments in the use of interlayers to tailor the Schottky barrier height (SBH) at a metal/GaAs interface are discussed. The goal has been to gain control of band bending in the interfacial region by modifying both the interface Fermi energy and the charge density in the depletion region. The approach has been to grow both the interlayer and the metal overlayer under ultrahigh vacuum conditions by molecular beam epitaxy, and then to determine the chemistry of interface formation, structure, and band bending by x-ray photoelectron spectroscopy and diffraction and by low-energy electron diffraction. The interface Fermi energy can bemore » changed from the usual midgap value of 0.7--0.8 eV relative to the band edge by the use of epitaxial transition metal aluminide (TMA) overlayers such as NiAl. The unique chemistry of interface formation between this intermetallic compound and GaAs pins the Fermi level {approximately}0.3--0.4 eV above the valence band maximum, and results in a SBH of {approximately}1 eV. The SBH can be increased to {approximately}1.2 eV by the use of a wide bandgap interlayer such as AlAs. The charge density in the depletion region can be changed by growing an n{sup +}-type group IV interlayer between the TMA overlayer and GaAs substrate. Charge transfer from the interlayer to an n-type substrate reduces the space charge density, and thereby lowers the band bending and, thus, the SBH to {approximately}0.5 eV. The use of these interlayers then produces a range of SBH values of {approximately}0.7 eV, which is a significant improvement over the rather narrow range of 0.1--0.2 eV that results from conventional metallizations. The fundamental interface science that underpins these results is discussed, and an application to complementary digital GaAs circuit design that may significantly reduce gate leakage is given.« less
  • The use of neutron scattering as a tool for exploring surfaces and interfaces has become more prevalent over the last several years, mainly due to the increasing popularity of reflectivity techniques, which study specular reflection from single surfaces or multilayers. Due to intensity limitations, the use of off-specular or grazing-incidence neutron scattering techniques has been much less prevalent. In this paper the authors shall discuss the origins of magnetic off-specular scattering and the origins of anomalies seen in the X-ray or neutron diffuse scattering from multilayers near Bragg reflections in terms of the Dynamical Theory of Scattering.