Determination of optical damage cross-sections and volumes surrounding ion bombardment tracks in GaAs using coherent acoustic phonon spectroscopy
Abstract
We report the results of coherent acoustic phonon spectroscopy analysis of band-edge optical modification of GaAs irradiated with 400 keV Ne++ for doses between 1011–1013 cm−2. We relate this optical modification to the structural damage density as predicted by simulation and verified by ion channeling analysis. Crystal damage is observed to cause optical modification that reduces the amplitude of the optoacoustic signal. The depth-dependent nature of the optoacoustic measurement allows us to determine optical damage cross-sections along the ion track, which are found to vary as a function of position along the track. Unexpectedly, we find that this optical modification is primarily dependent on the structural damage density and insensitive to the specific defect configuration along the ion track, suggesting that a simple model of defect density along the track is sufficient to characterize the observed optical changes. The extent of optical modification is strongly probe frequency-dependent as the frequency is detuned from the GaAs band edge. As determined from the experimental measurements, the spatial extent of optical modification exceeds the spatial extent of the structural disorder by an order of magnitude.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 01, 2012
- Source ID
- 10.1063/1.4732072
Entities
People
- A. B. Hmelo
- A. Steigerwald
- K. Varga
- L. C. Feldman
- N. Tolk
Organizations
- Army Research Office
- National Science Foundation
- Rutgers University
- United States Department of Energy
- Vanderbilt University