Arsenic oxide microcrystals in anodically processed GaAs electrochemical growth, spectroscopy, and morphology

Xiuling Li, P. W. Bohn

Research output: Contribution to journalArticle

Abstract

Anodic etching of GaAs wafers in concentrated HCl produces many As2O3 microcrystals (1-50 μm in size) on the GaAs substrate. The etching process and the nature of the luminescence from these GaAs surfaces have been explored in detail. The etch pits are initiated at point defect sites, not extended defects. High HCl concentration, high current density, as well as long etching times facilitate As2O3 microcrystal growth. Polarization-dependent Raman spectroscopy identified the As2O3 microcrystals and accessed symmetry changes of the GaAs surface induced by the electrochemical processing. Raman signals from quantum-size effect confined phonons in GaAs were not observed. Far-field photoluminescence of such samples shows a strong emission band centered around 540 nm. Spatially resolved spectroscopy and imaging (cathodoluminescence and near-field scanning optical microscopy) unambiguously indicate that the 540 nm emission comes from many weak emitters (As2O3). A few strong emitters originating from amorphous impurity inclusions are also identified in samples prepared in a macor cell.

Original languageEnglish (US)
Pages (from-to)1740-1746
Number of pages7
JournalJournal of the Electrochemical Society
Volume147
Issue number5
DOIs
StatePublished - May 1 2000

ASJC Scopus subject areas

  • Electrochemistry
  • Surfaces, Coatings and Films
  • Surfaces and Interfaces

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