Transient response of photodetectors

Calculations by drift diffusion and Monte Carlo methods and experimental data on the transient response of metal–semiconductor–metal photodetectors are reported. We have shown how the interplay of carrier and displacement currents, inhomogeneities in field and charge distributions, and hot electron effects determines observed structure in the transient response. In particular, we have demonstrated the role played by the regions under the contacts that are not illuminated in forming peaks in the transient response. We have also demonstrated that the peaks in the transient response need not be attributed to velocity overshoot and the scaling of detector response with contact separation has been studied.