Symmetry of GaAs1-xNx conduction-band minimum probed by resonant Raman scattering

초록

The nature of the conduction-band minimum of GaAs1-xNx (xless than or equal to0.7) is probed by performing resonant Raman scattering (RRS) on thin layers of GaAs1-xNx epitaxially grown on Ge substrates. Strong resonance enhancement of the LO-phonon Raman intensity is observed with excitation energies near the E-0 as well as E+ transitions. However, in contrast to the distinct LO-phonon linewidth resonance enhancement and activation of various X and L zone-boundary phonons brought about slightly below and near the E+ transition, respectively, we have not observed any resonant LO-phonon linewidth broadening or activation of sharp zone-boundary phonons near the E-0 transition. The observed RRS results reveal that the conduction-band minimum of GaAs1-xNx predominantly consists of the delocalized GaAs bulklike states of Gamma symmetry.

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