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Title: Spatially resolved band alignments at Au-hexadecanethiol monolayer-GaAs(001) interfaces by ballistic electron emission microscopy

Abstract

We study structural and electronic inhomogeneities in Metal—Organic Molecular monoLayer (OML)—semiconductor interfaces at the sub-nanometer scale by means of in situ Ballistic Electron Emission Microscopy (BEEM). BEEM imaging of Au/1-hexadecanethiols/GaAs(001) heterostructures reveals the evolution of pinholes density as a function of the thickness of the metallic top-contact. Using BEEM in spectroscopic mode in non-short-circuited areas, local electronic fingerprints (barrier height values and corresponding spectral weights) reveal a low-energy tunneling regime through the insulating organic monolayer. At higher energies, BEEM evidences new conduction channels, associated with hot-electron injection in the empty molecular orbitals of the OML. Corresponding band diagrams at buried interfaces can be thus locally described. The energy position of GaAs conduction band minimum in the heterostructure is observed to evolve as a function of the thickness of the deposited metal, and coherently with size-dependent electrostatic effects under the molecular patches. Such BEEM analysis provides a quantitative diagnosis on metallic top-contact formation on organic molecular monolayer and appears as a relevant characterization for its optimization.

Authors:
; ; ; ; ; ;  [1]
  1. Département Matériaux-Nanosciences, Institut de Physique de Rennes, UMR 6251, CNRS-Université de Rennes 1, Campus de Beaulieu, Bât 11E, 35042 Rennes Cedex (France)
Publication Date:
OSTI Identifier:
22494809
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 118; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALIGNMENT; DEPOSITION; ELECTRICAL FAULTS; ELECTRON BEAM INJECTION; ELECTRON EMISSION; ELECTRON MICROSCOPY; ELECTRONIC STRUCTURE; EMISSION SPECTROSCOPY; GALLIUM ARSENIDES; GOLD COMPOUNDS; LAYERS; OPTIMIZATION; SEMICONDUCTOR MATERIALS; SPATIAL RESOLUTION; TUNNEL EFFECT

Citation Formats

Junay, A., Guézo, S., E-mail: sophie.guezo@univ-rennes1.fr, Turban, P., Delhaye, G., Lépine, B., Tricot, S., Ababou-Girard, S., and Solal, F. Spatially resolved band alignments at Au-hexadecanethiol monolayer-GaAs(001) interfaces by ballistic electron emission microscopy. United States: N. p., 2015. Web. doi:10.1063/1.4928167.
Junay, A., Guézo, S., E-mail: sophie.guezo@univ-rennes1.fr, Turban, P., Delhaye, G., Lépine, B., Tricot, S., Ababou-Girard, S., & Solal, F. Spatially resolved band alignments at Au-hexadecanethiol monolayer-GaAs(001) interfaces by ballistic electron emission microscopy. United States. doi:10.1063/1.4928167.
Junay, A., Guézo, S., E-mail: sophie.guezo@univ-rennes1.fr, Turban, P., Delhaye, G., Lépine, B., Tricot, S., Ababou-Girard, S., and Solal, F. Fri . "Spatially resolved band alignments at Au-hexadecanethiol monolayer-GaAs(001) interfaces by ballistic electron emission microscopy". United States. doi:10.1063/1.4928167.
@article{osti_22494809,
title = {Spatially resolved band alignments at Au-hexadecanethiol monolayer-GaAs(001) interfaces by ballistic electron emission microscopy},
author = {Junay, A. and Guézo, S., E-mail: sophie.guezo@univ-rennes1.fr and Turban, P. and Delhaye, G. and Lépine, B. and Tricot, S. and Ababou-Girard, S. and Solal, F.},
abstractNote = {We study structural and electronic inhomogeneities in Metal—Organic Molecular monoLayer (OML)—semiconductor interfaces at the sub-nanometer scale by means of in situ Ballistic Electron Emission Microscopy (BEEM). BEEM imaging of Au/1-hexadecanethiols/GaAs(001) heterostructures reveals the evolution of pinholes density as a function of the thickness of the metallic top-contact. Using BEEM in spectroscopic mode in non-short-circuited areas, local electronic fingerprints (barrier height values and corresponding spectral weights) reveal a low-energy tunneling regime through the insulating organic monolayer. At higher energies, BEEM evidences new conduction channels, associated with hot-electron injection in the empty molecular orbitals of the OML. Corresponding band diagrams at buried interfaces can be thus locally described. The energy position of GaAs conduction band minimum in the heterostructure is observed to evolve as a function of the thickness of the deposited metal, and coherently with size-dependent electrostatic effects under the molecular patches. Such BEEM analysis provides a quantitative diagnosis on metallic top-contact formation on organic molecular monolayer and appears as a relevant characterization for its optimization.},
doi = {10.1063/1.4928167},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 8,
volume = 118,
place = {United States},
year = {2015},
month = {8}
}