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Title: Electron affinity of cubic boron nitride terminated with vanadium oxide

A thermally stable negative electron affinity (NEA) for a cubic boron nitride (c-BN) surface with vanadium-oxide-termination is achieved, and its electronic structure was analyzed with in-situ photoelectron spectroscopy. The c-BN films were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition employing BF{sub 3} and N{sub 2} as precursors. Vanadium layers of ∼0.1 and 0.5 nm thickness were deposited on the c-BN surface in an electron beam deposition system. Oxidation of the metal layer was achieved by an oxygen plasma treatment. After 650 °C thermal annealing, the vanadium oxide on the c-BN surface was determined to be VO{sub 2}, and the surfaces were found to be thermally stable, exhibiting an NEA. In comparison, the oxygen-terminated c-BN surface, where B{sub 2}O{sub 3} was detected, showed a positive electron affinity of ∼1.2 eV. The B{sub 2}O{sub 3} evidently acts as a negatively charged layer introducing a surface dipole directed into the c-BN. Through the interaction of VO{sub 2} with the B{sub 2}O{sub 3} layer, a B-O-V layer structure would contribute a dipole between the O and V layers with the positive side facing vacuum. The lower enthalpy of formation for B{sub 2}O{sub 3} is favorable for the formation of the B-O-V layer structure, which providesmore » a thermally stable surface dipole and an NEA surface.« less
Authors:
; ; ; ;  [1] ;  [2]
  1. Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)
  2. School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287-6106 (United States)
Publication Date:
OSTI Identifier:
22492875
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AFFINITY; BORATES; BORON FLUORIDES; BORON NITRIDES; BORON OXIDES; CHEMICAL VAPOR DEPOSITION; DIPOLES; ELECTRON BEAMS; ELECTRON CYCLOTRON-RESONANCE; ELECTRONIC STRUCTURE; FORMATION HEAT; LAYERS; PHOTOELECTRON SPECTROSCOPY; SURFACES; VANADIUM OXIDES