Impedance and switching of GaAs p-i-n diodes

The impedance of GaAs p-i-n diodes under forward bias is modeled using the two-dimensional simulation program PISCES. A parallel equivalent circuit gives almost constant resistance and capacitance over a wide range of frequencies. The intrinsic turn-off switching time of the diode, neglecting contact resistance, is determined by the sweep out time of the carriers, not by the carrier lifetime, unless this is very short. The diode current is recombination dominated at low forward bias. At higher applied voltages, this current becomes diffusion dominated if not masked by high injection conditions