Ar-sputtering of In0.52Al0.48As was investigated with room-temperature
Raman and photoluminescence spectroscopy. A clear increase of carrier
density in the near-surface region was observed in the Raman spectra.
The PL intensity was found to depend in a complex way on plasma self-
bias potential, incident laser irradiance, and InAlAs doping level, in
dicating that the recombination mechanisms dominating the PL response
differ with changing experimental conditions. The observed trends can
be explained by sputter-induced formation of an electron accumulation
layer in the near-surface region.