  An internal field induced resonant intensity enhancement of Raman scattering
of phonon excitations in InAs nanowires is reported. The experimental
observation is in good agreement with the simulated results for the scattering
of light under varying incident wavelengths, originating from the enhanced
internal electric field in an infinite dielectric cylinder. Our analysis
demonstrates the combined effect of the first higher lying direct band gap
energy (E1) and the refractive index of the InAs nanowires in the internal
field induced resonant Raman scattering. Furthermore, the difference in the
relative contribution of electro-optic effect and deformation potential in
Raman scattering of nanowires and bulk InAs over a range of excitation energies
is discussed by comparing the intensity ratio of their LO and TO phonon modes.
