  Under hot electron condition, the hot carriers phonon excited by ultra-short
pulses in polar semiconductors initially loose energy rapidly by emitting
longitudinal optic phonons via dominant Frolic coupling. Thus, energy supplied
to the carriers by high electric fields goes into phonon generation. As the
phonon life time is long enough, phonon distribution is disturbed and a non
equilibrium population of LO phonons or hot phonons are produced, leading to
their re-absorption by the carriers. In the present work the high frequency
performance of GaN nanostructures is studied in the framework of heated drifted
Fermi-Dirac distribution function incorporating the relevant scattering
mechanisms and the influence of non-equilibrium LO phonons. It is observed that
degradation of phonon distribution enhances significantly 3-dB cut off
frequency thereby makes the high frequency response flatter reflecting that
high frequency response is better if effects of non-equilibrium phonon
distributions are included in the calculations.
