Novel FTO/SRO/silicon optical sensors: characterization and applications

In this paper, we describe the electrical and optoelectronic properties of new metal-insulator-silicon optical sensors, in which the silicon rich oxide layer is used as leaky insulator. Due to a leakage current through the insulator layer, two possible operating modes have been found for sensors. At the first mode and at certain voltage bias, the sensors are likewise photodetectors with an abrupt p-n junction. The second operating mode when the sensors investigated have the properties of a "usual" MOS capacitor takes place at a lowered bias. We show the possibility of combining these operating modes by applying to the structure a mixed DC and pulse voltage bias. With this, transient processes taking place can be used for the design of new optical sensors with internal signal gain.