High-sensitivity transmission IR spectroscopy for the chemical identification and structural analysis of conjugated molecules on gallium arsenide surfaces

Dmitry A. Krapchetov, Hong Ma, Alex K.Y. Jen, Daniel A. Fischer, Yueh Lin Loo

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

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 4OH) concentration. NH 4OH is added to the assembly solution to convert the thioacetyl groups on the QPDT precursor to thiolates. When assembled at high NH 4OH concentrations, the acetyl groups are completely removed, and QPDT is disordered on GaAs. Assembly at low NH 4OH 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.

Original languageEnglish (US)
Pages (from-to)9491-9494
Number of pages4
JournalLangmuir
Volume22
Issue number23
DOIs
StatePublished - Nov 7 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

Fingerprint Dive into the research topics of 'High-sensitivity transmission IR spectroscopy for the chemical identification and structural analysis of conjugated molecules on gallium arsenide surfaces'. Together they form a unique fingerprint.

  • Cite this