The current responsivity of the photo detector is determined by the quantum efficiency,; and by the photoelectric gain, g:
The quantum efficiency value describes how well the detector is coupled to the radiation to be detected. It is usually defined as the number of electron–hole pairs generated per incident photon.
The idea of photoconductive gain, g; was put forth by Rose as a simplifying concept for the understanding of photoconductive phenomena and is now widely used in the field.
The photoelectric gain is the number of carriers passing contacts per one generated pair. This value shows how well the generatedelect ron–hole pairs are used to generate the current response of a photodetector. Both values are assumed here as constant over the volume of the device
current resonsivity will be= ((wavelength* QE*q*g)/(hc))
