Chemical engineering of gallium arsenide surfaces with 4′-methyl-4-mercaptobiphenyl and 4′-hydroxy-4-mercaptobiphenyl monolayers

K. Adlkofer, A. Shaporenko, M. Zharnikov, M. Grunze, A. Ulman, M. Tanaka

Research output: Contribution to journalArticle

Abstract

Stable chemical engineering of stoichiometric GaAs [100] surfaces was achieved by deposition of two types of mercaptobiphenyls: 4′-methyl-4-mercaptobiphenyl and 4′-hydroxy-4-mercaptobiphenyl, which can render the surface hydrophobic and hydrophilic, respectively. Topography of the engineered surface was studied by atomic force microscopy (AFM), and the covalent binding between the thiolate and surface arsenide was confirmed by high-resolution X-ray photoelectron spectroscopy (HRXPS). Total surface free energies of the engineered surfaces as well as its dispersive and polar components were calculated from contact angle measurements. Electrochemical properties of the engineered GaAs in aqueous electrolytes were measured by impedance spectroscopy at a cathodic potential (-350 mV), demonstrating that both types of mercaptobiphenyls can form stable monolayers with high electric resistances, R > 2 MΩ cm2. The surface engineering method established here allows for control of surface free energies toward deposition of model biomembranes on GaAs-based device surfaces.

Original languageEnglish (US)
Pages (from-to)11737-11741
Number of pages5
JournalJournal of Physical Chemistry B
Volume107
Issue number42
DOIs
StatePublished - Oct 23 2003

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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