Raman study of luminescent spark processed porous GaAs

Abstract

We have analyzed spark-processed porous GaAs ~spp-GaAs! samples prepared by the application of high-voltage discharges at low repetition rates ~20 Hz! in different ambients, ranging from pure nitrogen to pure oxygen flow, using a microRaman probe and a scanning electron microscope in combination with an energy dispersive spectroscopy system ~SEM-EDS!.We found that for samples prepared in pure nitrogen, the resulting material is basically amorphous material, with amorphous-GaAs with some cubic phase of As2O3 also present. For samples prepared under even a low concentration of oxygen, 20:1, we find that the cubic phase of As2O3 is substituted by the monoclinic phase of As2O3 ‘‘claudetite.’’ SEM micrographs show the resultant morphologies obtained that exhibit a porous, granular, agglomerated granular appearance. EDS and Raman suggest that the claudetite phase of As2O3 and As2O5 play a contributing role in the green-blue photoluminescence emitted by spp-GaAs. © 2001 American Vacuum Society. DOI: 10.1116/1.1366709