Abstract
The reaction chemistry of H-terminated crystalline Si(111) and Si(100) surfaces in CH3OH, CD3OD, CF3(CH2)3OH, C4H9OH, and C4D9OD solutions containing ferrocenium (Fc+)-BF4, I2, or Br2 was monitored using X-ray photoelectron (XP) spectroscopy and infrared (IR) spectroscopy. Addition of the one-electron oxidant Fc+, or addition of the oxidizing species I2 or Br2, produced diagnostic changes in the IR spectra that clearly indicated formation of surficial Si-OR groups. XPS data confirmed the conclusions of the IR studies: Under our reaction conditions, no detectable reaction occurred without the presence of the oxidant. The data are consistent with oxidative activation of the surficial Si-H bonds toward nucleophilic attack by the alcohols. The reaction chemistry was generally similar on (111)-and (100)-oriented Si surfaces, although some differences were observed in the ratio of reaction products on the two different surface orientations. Alkoxylated surfaces were also prepared by a two-step process in which the surface was first chlorinated and then reacted with LiOCH3, LiOCD3, or LiO(CH2)3CF3. The data indicate that formation of silicon-halogen bonding alone is not sufficient to provide a robust correlation between the electronic and chemical properties of such crystalline Si surfaces and that formation of silicon-alkoxyl bonds is a common motif for surfaces often used in electronic and electrochemical studies of Si.
| Original language | English |
|---|---|
| Pages (from-to) | 3639-3656 |
| Number of pages | 18 |
| Journal | Journal of Physical Chemistry B |
| Volume | 106 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - Apr 11 2002 |
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- Physical and Theoretical Chemistry
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Infrared and X-ray photoelectron spectroscopic studies of the reactions of hydrogen-terminated crystalline Si(111) and Si(100) surfaces with Br2, I2, and ferrocenium in alcohol solvents. / Haber, Joel A.; Lewis, Nathan S.
In: Journal of Physical Chemistry B, Vol. 106, No. 14, 11.04.2002, p. 3639-3656.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Infrared and X-ray photoelectron spectroscopic studies of the reactions of hydrogen-terminated crystalline Si(111) and Si(100) surfaces with Br2, I2, and ferrocenium in alcohol solvents
AU - Haber, Joel A.
AU - Lewis, Nathan S
PY - 2002/4/11
Y1 - 2002/4/11
N2 - The reaction chemistry of H-terminated crystalline Si(111) and Si(100) surfaces in CH3OH, CD3OD, CF3(CH2)3OH, C4H9OH, and C4D9OD solutions containing ferrocenium (Fc+)-BF4, I2, or Br2 was monitored using X-ray photoelectron (XP) spectroscopy and infrared (IR) spectroscopy. Addition of the one-electron oxidant Fc+, or addition of the oxidizing species I2 or Br2, produced diagnostic changes in the IR spectra that clearly indicated formation of surficial Si-OR groups. XPS data confirmed the conclusions of the IR studies: Under our reaction conditions, no detectable reaction occurred without the presence of the oxidant. The data are consistent with oxidative activation of the surficial Si-H bonds toward nucleophilic attack by the alcohols. The reaction chemistry was generally similar on (111)-and (100)-oriented Si surfaces, although some differences were observed in the ratio of reaction products on the two different surface orientations. Alkoxylated surfaces were also prepared by a two-step process in which the surface was first chlorinated and then reacted with LiOCH3, LiOCD3, or LiO(CH2)3CF3. The data indicate that formation of silicon-halogen bonding alone is not sufficient to provide a robust correlation between the electronic and chemical properties of such crystalline Si surfaces and that formation of silicon-alkoxyl bonds is a common motif for surfaces often used in electronic and electrochemical studies of Si.
AB - The reaction chemistry of H-terminated crystalline Si(111) and Si(100) surfaces in CH3OH, CD3OD, CF3(CH2)3OH, C4H9OH, and C4D9OD solutions containing ferrocenium (Fc+)-BF4, I2, or Br2 was monitored using X-ray photoelectron (XP) spectroscopy and infrared (IR) spectroscopy. Addition of the one-electron oxidant Fc+, or addition of the oxidizing species I2 or Br2, produced diagnostic changes in the IR spectra that clearly indicated formation of surficial Si-OR groups. XPS data confirmed the conclusions of the IR studies: Under our reaction conditions, no detectable reaction occurred without the presence of the oxidant. The data are consistent with oxidative activation of the surficial Si-H bonds toward nucleophilic attack by the alcohols. The reaction chemistry was generally similar on (111)-and (100)-oriented Si surfaces, although some differences were observed in the ratio of reaction products on the two different surface orientations. Alkoxylated surfaces were also prepared by a two-step process in which the surface was first chlorinated and then reacted with LiOCH3, LiOCD3, or LiO(CH2)3CF3. The data indicate that formation of silicon-halogen bonding alone is not sufficient to provide a robust correlation between the electronic and chemical properties of such crystalline Si surfaces and that formation of silicon-alkoxyl bonds is a common motif for surfaces often used in electronic and electrochemical studies of Si.
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U2 - 10.1021/jp0102872
DO - 10.1021/jp0102872
M3 - Article
VL - 106
SP - 3639
EP - 3656
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 14
ER -