Response time of amorphous selenium based photodetector driven by diamond cold cathode

We investigated the response time of a-Se based vacuum photodetector driven by diamond cold cathode. To characterize the response time, the a-Se surface was illuminated using pulsating white light and the variation of emission current from diamond field emitter was measured on an oscilloscope. The results show that there is a relationship between the response time, measured through the time constant, and the quantum efficiency. As the quantum efficiency increases, the detector time constant decreases.