Resonant polar-optical-phonon modulation of Schottky barrier charging dynamics

The dynamical behavior of GaAs-based Schottky-diode interfaces near the pol ar-optical-phonon (POP) resonance frequency is addressed. The manifestation of a THz-regime coupling mechanism between the temporal evolution of the d iode barrier and POP's is revealed. Specifically, POP's are shown to pertur b the spatial dependence of the displacement field within the depletion reg ion, and strongly enhance the nonlinearity associated with diode current. T his resonance coupling emerges in the unscreened barrier region and leads t o dramatic nonlinear effects on both the resistive (i.e., emission particle transport) and the reactive (displacement transport) physics. Specifically , the spatial depth of the space-charge region is reduced leading to a larg e tunneling current. Furthermore, the phase coherence of the dynamical char ging is modified resulting in an increased higher-harmonic current-density generation.