Covalent Attachment to GaP(110) -- Engineering the Chemical Functionalization of a III-V Semiconductor

ORAL

Abstract

With its 2.3 eV bulk bandgap, relatively high conduction band edge, and low chemical reactivity, the (110) surface of GaP is an excellent candidate for many UV and visible light applications, such as photo-catalysis and light-induced chemical reduction. However, the reconstruction and resulting charge transfer of the surface makes it difficult to covalently attach the required molecules. Indeed, very little work has been done to understand either covalent functionalization or passivation of this surface. Here we report on a Staudinger-type, thermally-driven covalent attachment of perfluorophenyl azide (pfpa) to GaP(110). We have studied the adsorption of pfpa molecules by means of high-resolution scanning tunneling microscopy and spectroscopy in combination with first principles calculations. We show a progression from a physisorbed state at room temperature to a covalently attached state after exposure to slightly higher temperatures ($\sim$ 50$^{\circ}$C). The developed approach is expected to be valid for various other functional groups attached to the azide, as well as other III-V semiconductors. \\[4pt] [1] J.L.A. Alves, et. al.\textit{Phys. Rev. B.}, 6188-6198.\\[0pt] [2] M.M. Ugeda, et. al.\textit{J. Phys. Chem. C.}(accepted November 2013).

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Authors

  • A.J. Bradley

    UC Berkeley, Dept of Physics

  • Miguel Ugeda

    UC Berkeley, Physics; LBNL, UC Berkeley, Dept of Phsyics; JCAP, LBNL, UC Berkeley physics

  • Wenjun Liu

    UC Berkeley, Dept of Chemistry; JCAP, LBNL

  • Min Yu

    JCAP, LBNL; Materials Science Division, LBNL

  • T. Don Tilley

    UC Berkeley, Dept of Chemistry

  • Rub\'en P\'erez

    Dept. F\'isica Te\'orica de la Materia Condensada, UAM, Madrid

  • Jeffery B. Neaton

    Department of Physics, UC-Berkeley; Molecular Foundry, LBNL, Molecular Foundry, LBNL, Department of Physics, UC Berkeley, Molecular Foundry, LBNL and Dept. Physics, UC Berkeley, Molecular Foundry, Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, UC Berkeley, Dept of Physics; Materials Science Division, LBNL, Molecular Foundry, Lawrence Berkeley National Laboratory; Department of Physics, UC-Berkeley, The Molecular Foundry, LBNL; Dept. of Physics, University of California, Berkeley, Lawrence Berkeley National Laboratory, UC Berkeley Department of Physics, Lawrence Berkeley Natl Lab and Department of Physics, UC-Berkeley, Physics Department, UC Berkeley; Molecular Foundry, Lawrence Berkeley National Lab

  • Michael Crommie

    UC Berkeley, Physics; LBNL, UC Berkeley, Dept of Physics; Materials Science Division, LBNL, UC Berkeley physics/ LBNL MSD, Univ of California - Berkeley, University of California, Berkeley, UC Berkeley Physics Dept. and LBL Materials Sciences Division, University of Carlifornia at Berkeley