Amorphous silicon balanced photodiode for application in biomolecular analysis

In this work we present an amorphous silicon/amorphous silicon carbide balanced photodiode structure suitable for differential photocurrent measurements in the ultraviolet (UV) and visible range. The device is a three-terminal structure constituted by two series-connected amorphous silicon p-i-n photodiodes. The structure takes advantage of the differential measurement to reveal very small variations of photocurrent in a large background current signal. Application of the device in detection of biomolecules based on the use of photosensors, can allow the increase of both the dynamic range and the sensitivity of the measurement.