Raman scattering studies in H + and He + implanted n-GaAs

Abstract

The liquid encapsulated czochralski (LEC) grown (1 0 0) oriented n-GaAs have been implanted with low energy H + and He + for various doses ranging from 10 13–10 17 cm −2. Raman spectra of as-grown, H + and He + implanted n-GaAs are recorded and analysed. Full width at half maximum (FWHM) of the LO mode decreases up to a dose of 10 15 cm −2 for H + and 10 13 cm −2 for He + and increases at higher doses. Mode narrowing is accompanied by an increase of the area under the peak, while the area under the peak decreases when the mode broadens. The peak position remains almost the same at low doses but decreases at high doses. These results are explained with carrier concentration reduction at low doses and lattice damage at high doses. Annealing of the high dose implanted n-GaAs reduces the FWHM of the LO mode and increases the area under the peak and the peak frequency, due to the annealing of the implantation induced lattice damage.