Numerical Modeling of the Transient Response of Metal-Semiconductor-Metal Photodetector Using Discrete Fourier Transform Method

A one dimensional (1-D) simulation program based on the drift-diffusion model and Discrete Fourier Transform method (DFT) is developed. This program numerically solves the time-dependent continuity equations for electrons and holes in a semiconductor device. This model simulates carrier concentrations and the impulse response of a GaAs metal-semiconductor-metal (MSM) photodetector at a constant bias voltage. From this simulation, we found that for a smaller value of carrier lifetime, the response fall time decreases without significantly reducing the responsivity of the device. The simulation results are well in agreement with the experimental finding and our results match the work of other people who have done the same simulation but with different approach.