Effect of the optical excitation signal intensity on the impulse response of a metal-semiconductor-metal photodiode

The effect of the optical excitation signal intensity on the impulse response of a photodetector based on a set of metal-semiconductor-metal (MSM) rectifier contacts is studied. The response of the detector is better at a low optical excitation signal. When the energy of an optical excitation pulse is high, the response can be improved by increasing the bias voltage. The advantages of a GaN-based MSM diode in detecting high- energy radiation pulses are established. It is shown that the speed of the GaN-based MSM detector may reach 25 ps for a 60-pJ optical excitation pulse at a wavelength of 290 nm.