Photodetector and photodetection method using the same

摘要

Disclosed is a photodetector adapted to detect light having a predetermined level of photon energy, comprising: a first semiconductor layer, a second semiconductor layer having a quantum well or a quantum line structure, a barrier layer provided between the first and second semiconductor layers, a device for applying voltage to the barrier layer and the first and second semiconductor layers in order to generate a tunnel current flowing through the barrier layer, and a device for detecting the tunnel current. The second semiconductor layer exhibits a plurality of electron levels, the energy difference between which is slightly smaller or slightly larger than the photon energy of the detected light. Further, incidence of the detected light upon the second semiconductor layer causes the electron levels to shift by the photo Stark effect, resulting in variation of the tunnel current.