TY - JOUR
T1 - Control of the pH-dependence of the band edges of Si(111) surfaces using mixed methyl/allyl monolayers
AU - Johansson, Erik
AU - Boettcher, Shannon W.
AU - O'Leary, Leslie E.
AU - Poletayev, Andrey D.
AU - Maldonado, Stephen
AU - Brunschwig, Bruce S.
AU - Lewis, Nathan S.
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/5/5
Y1 - 2011/5/5
N2 - The open-circuit potentials of p-Si/((MV2+/MV+) (aq)) junctions with Si(111) surfaces functionalized with H-, CH 3-, CH2CHCH2-, or mixed CH3-/CH 2CHCH2- monolayers have been investigated as the solution pH was changed from 2.5 to 11. The pH sensitivity of the open-circuit potentials, and therefore the band-edge positions, was anticorrelated with the total fraction of Si atop sites that were terminated by Si-C bonds. This behavior is consistent with the hypothesis that the non Si-C terminated atop sites were initially H-terminated and were unstable to oxide growth under aqueous conditions with the oxidation-product inducing a pH-dependent dipole. Metal-semiconductor junctions between Hg and CH3-, CH 2CHCH2-, or mixed CH3-/CH2CHCH 2-terminated n-Si(111) surfaces formed rectifying Hg/Si Schottky junctions and exhibited mutually similar barrier-heights (̃0.9 V), suggesting similar magnitudes and direction of the surface dipoles on all of these functionalized surfaces.
AB - The open-circuit potentials of p-Si/((MV2+/MV+) (aq)) junctions with Si(111) surfaces functionalized with H-, CH 3-, CH2CHCH2-, or mixed CH3-/CH 2CHCH2- monolayers have been investigated as the solution pH was changed from 2.5 to 11. The pH sensitivity of the open-circuit potentials, and therefore the band-edge positions, was anticorrelated with the total fraction of Si atop sites that were terminated by Si-C bonds. This behavior is consistent with the hypothesis that the non Si-C terminated atop sites were initially H-terminated and were unstable to oxide growth under aqueous conditions with the oxidation-product inducing a pH-dependent dipole. Metal-semiconductor junctions between Hg and CH3-, CH 2CHCH2-, or mixed CH3-/CH2CHCH 2-terminated n-Si(111) surfaces formed rectifying Hg/Si Schottky junctions and exhibited mutually similar barrier-heights (̃0.9 V), suggesting similar magnitudes and direction of the surface dipoles on all of these functionalized surfaces.
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U2 - 10.1021/jp109799e
DO - 10.1021/jp109799e
M3 - Article
AN - SCOPUS:79955556883
VL - 115
SP - 8594
EP - 8601
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 17
ER -