Arsenic oxide microcrystals in anodically processed GaAs: Electrochemical growth, spectroscopy, and morphology
Anodic etching of GaAs wafers in concentrated HCl produces many As{sub 2}O{sub 3} microcrystals (1--50 {micro}m 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 As{sub 2}O{sub 3} microcrystal growth. Polarization-dependent Raman spectroscopy identified the As{sub 2}O{sub 3} microcrystals and accessed symmetry changes of the GaAs surface induced by the electrochemical processing Raman signals from quantum-size effect confined phonons in Ga As 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 (As{sub 2}O{sub 3}). A few strong emitters originating from amorphous impurity inclusions are also identified in samples prepared in a macor cell.
- Research Organization:
- Univ. of Illinois, Urbana, IL (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 20080572
- Journal Information:
- Journal of the Electrochemical Society, Vol. 147, Issue 5; Other Information: PBD: May 2000; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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