Electrically tuneable spectral responsivity in gated silicon photodiodes

Abstract

We report the observation of electrically tuneable spectral responsivity in silicon-based photodetectors. The current flowing through a lateral p-i-n junction photodiode can be changed by changing either the gate bias or the intensity of incident light, with the devices exhibiting typical optical responsivities of 65 A/W. The peak sensitivity of the device can be changed over the entire visible region by changing the gate voltage in a 5 V range. This happens because with increasing gate bias, an accumulation layer of holes is pulled closer to the Si-SiO2 interface, enhancing the blue response of the device.