Article
Processing of porous GaAs at low frequency sparking
Autor
ROJAS LÓPEZ, MARLON
Institución
Resumen
We report on the preparation of photoluminescent porous GaAs by the application of high voltage
spark discharges at low repetition rates ~20 Hz! in air and in argon atmospheres. The
spark-processed porous ~spp! samples were characterized by the observation of their visible
photoluminescence ~PL! when illuminated with UV monochromatic radiation. In contrast to
previous work on spp-GaAs at high sparking frequencies we find that the PL of samples prepared
at low sparking frequency is highly reproducible from sample to sample. Important differences are
observed in the initial PL spectra of the spp-GaAs according to the atmosphere of preparation under
similar conditions. After prolonged air exposure both the spp-GaAs prepared in air and in argon
show two similar broad peaks at energy positions 2.5 and 3.1 eV. Raman results indicate that the PL
might not be associated to any size dependent mechanism. We present evidence that oxygen
compounds formed by the exposure to air of the samples play a role in the PL excited in the
spp-GaAs. This is reinforced by x-ray photoelectronic spectroscopy measurements that indicate that
the spp-GaAs is covered by an oxidized film. © 1999 American Vacuum Society.
S0734-2101(99)03002-X