Nonstationary and nonlinear response of a p-i-n photodiode made of a two-valley semiconductor

The influence of nonstationary and nonlinear effects on carrier transport in a p-i-n photodiode made of a two-valley semiconductor is analyzed. A phenomenological model based on a two-valley conduction-band model is used, incorporating transition rates for intervalley electron transfer into the continuity equations and the drift-diffusion equations for carrier transport. A large optical power absorption in a small device can perturb, via the space-charge potential, the electric field which governs the carrier transport, and thus give rise to a nonlinear electrical response. The influence of these effects on photodiode response to pulsed light stimulation under various reverse-bias voltages is calculated.