We report direct-backscattering Raman studies of GaAs1-xNx alloys, for x≤0.03, grown on (001) GaAs. The Raman spectra exhibit a two-mode behavior. The allowed GaAs-like longitudinal-optic phonon near 292cm-1 is found to red shift at a rate of -136±10cm-1/x. This is well described by the combined effects of strain and alloying. The GaN-like phonon near 470cm-1 is observed to increase in intensity in direct proportion to x, and to systematically blue shift at a rate of 197±10cm-1/x. This blue shift is likewise attributed to strain and alloying. The GaAs-like second-order features are also seen to broaden slightly and diminish in intensity with increasing nitrogen concentration. These results are attributed to a weak breakdown in the zincblende-crystal long-range order, possibly related to the presence of ordered domains within the random alloy.
|Number of pages||3|
|Journal||Applied Physics Letters|
|State||Published - 1998|