Control of the Band-Edge Positions of Crystalline Si(111) by Surface Functionalization with 3,4,5-Trifluorophenylacetylenyl Moieties

Noah T. Plymale, Anshul A. Ramachandran, Allison Lim, Bruce S. Brunschwig, Nathan S Lewis

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Functionalization of semiconductor surfaces with organic moieties can change the charge distribution, surface dipole, and electric field at the interface. The modified electric field will shift the semiconductor band-edge positions relative to those of a contacting phase. Achieving chemical control over the energetics at semiconductor surfaces promises to provide a means of tuning the band-edge energetics to form optimized junctions with a desired material. Si(111) surfaces functionalized with 3,4,5-trifluorophenylacetylenyl (TFPA) groups were characterized by transmission infrared spectroscopy, X-ray photoelectron spectroscopy, and surface recombination velocity measurements. Mixed methyl/TFPA-terminated (MMTFPA) n- and p-type Si(111) surfaces were synthesized and characterized by electrochemical methods. Current density versus voltage and Mott-Schottky measurements of Si(111)-MMTFPA electrodes in contact with Hg indicated that the barrier height, φb, was a function of the fractional monolayer coverage of TFPA (θTFPA) in the alkyl monolayer. Relative to Si(111)-CH3 surfaces, Si(111)-MMTFPA samples with high θTFPA produced shifts in φb of ≥0.6 V for n-Si/Hg contacts and ≥0.5 V for p-Si/Hg contacts. Consistently, the open-circuit potential (Eoc) of Si(111)-MMTFPA samples in contact with CH3CN solutions that contained the 1-electron redox couples decamethylferrocenium/decamethylferrocene (Cp∗2Fe+/0) or methyl viologen (MV2+/+) shifted relative to Si(111)-CH3 samples by +0.27 V for n-Si and by up to +0.10 V for p-Si. Residual surface recombination limited the Eoc of p-Si samples at high θTFPA despite the favorable shift in the band-edge positions induced by the surface modification process.

Original languageEnglish
Pages (from-to)14157-14169
Number of pages13
JournalJournal of Physical Chemistry C
Volume120
Issue number26
DOIs
Publication statusPublished - Jul 7 2016

Fingerprint

Crystalline materials
Semiconductor materials
Monolayers
shift
Electric fields
Paraquat
Charge distribution
electric fields
Velocity measurement
Contacts (fluid mechanics)
Surface treatment
velocity measurement
Infrared spectroscopy
charge distribution
Current density
X ray photoelectron spectroscopy
Tuning
infrared spectroscopy
tuning
photoelectron spectroscopy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Control of the Band-Edge Positions of Crystalline Si(111) by Surface Functionalization with 3,4,5-Trifluorophenylacetylenyl Moieties. / Plymale, Noah T.; Ramachandran, Anshul A.; Lim, Allison; Brunschwig, Bruce S.; Lewis, Nathan S.

In: Journal of Physical Chemistry C, Vol. 120, No. 26, 07.07.2016, p. 14157-14169.

Research output: Contribution to journalArticle

Plymale, Noah T. ; Ramachandran, Anshul A. ; Lim, Allison ; Brunschwig, Bruce S. ; Lewis, Nathan S. / Control of the Band-Edge Positions of Crystalline Si(111) by Surface Functionalization with 3,4,5-Trifluorophenylacetylenyl Moieties. In: Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 26. pp. 14157-14169.
@article{30836657b192498cab39e214a09b32d3,
title = "Control of the Band-Edge Positions of Crystalline Si(111) by Surface Functionalization with 3,4,5-Trifluorophenylacetylenyl Moieties",
abstract = "Functionalization of semiconductor surfaces with organic moieties can change the charge distribution, surface dipole, and electric field at the interface. The modified electric field will shift the semiconductor band-edge positions relative to those of a contacting phase. Achieving chemical control over the energetics at semiconductor surfaces promises to provide a means of tuning the band-edge energetics to form optimized junctions with a desired material. Si(111) surfaces functionalized with 3,4,5-trifluorophenylacetylenyl (TFPA) groups were characterized by transmission infrared spectroscopy, X-ray photoelectron spectroscopy, and surface recombination velocity measurements. Mixed methyl/TFPA-terminated (MMTFPA) n- and p-type Si(111) surfaces were synthesized and characterized by electrochemical methods. Current density versus voltage and Mott-Schottky measurements of Si(111)-MMTFPA electrodes in contact with Hg indicated that the barrier height, φb, was a function of the fractional monolayer coverage of TFPA (θTFPA) in the alkyl monolayer. Relative to Si(111)-CH3 surfaces, Si(111)-MMTFPA samples with high θTFPA produced shifts in φb of ≥0.6 V for n-Si/Hg contacts and ≥0.5 V for p-Si/Hg contacts. Consistently, the open-circuit potential (Eoc) of Si(111)-MMTFPA samples in contact with CH3CN solutions that contained the 1-electron redox couples decamethylferrocenium/decamethylferrocene (Cp∗2Fe+/0) or methyl viologen (MV2+/+) shifted relative to Si(111)-CH3 samples by +0.27 V for n-Si and by up to +0.10 V for p-Si. Residual surface recombination limited the Eoc of p-Si samples at high θTFPA despite the favorable shift in the band-edge positions induced by the surface modification process.",
author = "Plymale, {Noah T.} and Ramachandran, {Anshul A.} and Allison Lim and Brunschwig, {Bruce S.} and Lewis, {Nathan S}",
year = "2016",
month = "7",
day = "7",
doi = "10.1021/acs.jpcc.6b03824",
language = "English",
volume = "120",
pages = "14157--14169",
journal = "Journal of Physical Chemistry C",
issn = "1932-7447",
publisher = "American Chemical Society",
number = "26",

}

TY - JOUR

T1 - Control of the Band-Edge Positions of Crystalline Si(111) by Surface Functionalization with 3,4,5-Trifluorophenylacetylenyl Moieties

AU - Plymale, Noah T.

AU - Ramachandran, Anshul A.

AU - Lim, Allison

AU - Brunschwig, Bruce S.

AU - Lewis, Nathan S

PY - 2016/7/7

Y1 - 2016/7/7

N2 - Functionalization of semiconductor surfaces with organic moieties can change the charge distribution, surface dipole, and electric field at the interface. The modified electric field will shift the semiconductor band-edge positions relative to those of a contacting phase. Achieving chemical control over the energetics at semiconductor surfaces promises to provide a means of tuning the band-edge energetics to form optimized junctions with a desired material. Si(111) surfaces functionalized with 3,4,5-trifluorophenylacetylenyl (TFPA) groups were characterized by transmission infrared spectroscopy, X-ray photoelectron spectroscopy, and surface recombination velocity measurements. Mixed methyl/TFPA-terminated (MMTFPA) n- and p-type Si(111) surfaces were synthesized and characterized by electrochemical methods. Current density versus voltage and Mott-Schottky measurements of Si(111)-MMTFPA electrodes in contact with Hg indicated that the barrier height, φb, was a function of the fractional monolayer coverage of TFPA (θTFPA) in the alkyl monolayer. Relative to Si(111)-CH3 surfaces, Si(111)-MMTFPA samples with high θTFPA produced shifts in φb of ≥0.6 V for n-Si/Hg contacts and ≥0.5 V for p-Si/Hg contacts. Consistently, the open-circuit potential (Eoc) of Si(111)-MMTFPA samples in contact with CH3CN solutions that contained the 1-electron redox couples decamethylferrocenium/decamethylferrocene (Cp∗2Fe+/0) or methyl viologen (MV2+/+) shifted relative to Si(111)-CH3 samples by +0.27 V for n-Si and by up to +0.10 V for p-Si. Residual surface recombination limited the Eoc of p-Si samples at high θTFPA despite the favorable shift in the band-edge positions induced by the surface modification process.

AB - Functionalization of semiconductor surfaces with organic moieties can change the charge distribution, surface dipole, and electric field at the interface. The modified electric field will shift the semiconductor band-edge positions relative to those of a contacting phase. Achieving chemical control over the energetics at semiconductor surfaces promises to provide a means of tuning the band-edge energetics to form optimized junctions with a desired material. Si(111) surfaces functionalized with 3,4,5-trifluorophenylacetylenyl (TFPA) groups were characterized by transmission infrared spectroscopy, X-ray photoelectron spectroscopy, and surface recombination velocity measurements. Mixed methyl/TFPA-terminated (MMTFPA) n- and p-type Si(111) surfaces were synthesized and characterized by electrochemical methods. Current density versus voltage and Mott-Schottky measurements of Si(111)-MMTFPA electrodes in contact with Hg indicated that the barrier height, φb, was a function of the fractional monolayer coverage of TFPA (θTFPA) in the alkyl monolayer. Relative to Si(111)-CH3 surfaces, Si(111)-MMTFPA samples with high θTFPA produced shifts in φb of ≥0.6 V for n-Si/Hg contacts and ≥0.5 V for p-Si/Hg contacts. Consistently, the open-circuit potential (Eoc) of Si(111)-MMTFPA samples in contact with CH3CN solutions that contained the 1-electron redox couples decamethylferrocenium/decamethylferrocene (Cp∗2Fe+/0) or methyl viologen (MV2+/+) shifted relative to Si(111)-CH3 samples by +0.27 V for n-Si and by up to +0.10 V for p-Si. Residual surface recombination limited the Eoc of p-Si samples at high θTFPA despite the favorable shift in the band-edge positions induced by the surface modification process.

UR - http://www.scopus.com/inward/record.url?scp=84978136428&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84978136428&partnerID=8YFLogxK

U2 - 10.1021/acs.jpcc.6b03824

DO - 10.1021/acs.jpcc.6b03824

M3 - Article

VL - 120

SP - 14157

EP - 14169

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 26

ER -