High-Sensitivity Transmission IR Spectroscopy for the Chemical Identification and Structural Analysis of Conjugated Molecules on Gallium Arsenide Surfaces
We demonstrate the use of high-sensitivity, off-normal transmission IR spectroscopy with s-polarized light to probe the chemical identity and orientation of quaterphenyldithiol (QPDT) molecular assemblies on GaAs as a function of ammonium hydroxide (NH{sub 4}OH) concentration. NH{sub 4}OH is added to the assembly solution to convert the thioacetyl groups on the QPDT precursor to thiolates. When assembled at high NH{sub 4}OH concentrations, the acetyl groups are completely removed, and QPDT is disordered on GaAs. Assembly at low NH{sub 4}OH concentrations, however, results in QPDT assemblies that are preferentially upright. The molecular orientation is further quantified with near-edge X-ray absorption fine structure spectroscopy.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 930167
- Report Number(s):
- BNL-80825-2008-JA; LANGD5; TRN: US200822%%1215
- Journal Information:
- Langmuir, Vol. 22; ISSN 0743-7463
- Country of Publication:
- United States
- Language:
- English
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