Symmetry of GaAs_{1 -x}N_x conduction-band minimum probed by resonant raman scattering

The nature of the conduction-band minimum of GaAs_{1 - x}N_x (x≤0.7) is probed by performing resonant Raman scattering (RRS) on thin layers of GaAs_{1 - x}N_x epitaxially grown on Ge substrates. Strong resonance enhancement of the LO-phonon Raman intensity is observed with excitation energies near the E₀ 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 E₀ transition. The observed RRS results reveal that the conduction-band minimum of GaAs_{1 - x}N_x predominantly consists of the delocalized GaAs bulklike states of F symmetry.