Pd growth and subsequent Schottky barrier formation on chemical vapor cleaned p-type GaN surfaces

P. J. Hartlieb, A. Roskowski, R. F. Davis, W. Platow, R. J. Nemanich

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Abstract

Characterization of chemical vapor cleaned, Mg-doped, p-type GaN(0001) surfaces and Pd contacts sequentially deposited on these surfaces has been conducted using x-ray and ultraviolet photoelectron spectroscopies and low-energy electron diffraction. The band bending and the electron affinity at the cleaned p-GaN surface were 1.4±0.1eV and 3.1±0.1eV, respectively. A previously unidentified band of surface states was observed at ∼1.0 eV below the Fermi level on this surface. The Pd grew epitaxially on the cleaned surface in a layer-by-layer mode and formed an abrupt, unreacted metal-semiconductor interface. The induced Fermi level movement with Pd deposition has been attributed to a complex interaction between extrinsic and intrinsic surface states as well as metal induced gap states. The final Schottky barrier height at the Pd/p-GaN interface was 1.3±0.1eV; the interface dipole contribution was 0.4±0.1eV.

Original languageEnglish (US)
Pages (from-to)732-738
Number of pages7
JournalJournal of Applied Physics
Volume91
Issue number2
DOIs
StatePublished - Jan 15 2002
Externally publishedYes

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

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