Photo and dark current noise in self-assembled quantum dot infrared photodetectors

摘要

Current noise is investigated in InAs/GaAs self-assembled quantum dot infrared photodetectors in the dark and under irradiation at T = 4.2 K. At low temperature, the noise is consistent with a mechanism of fluctuations driven by the electric field, related to field- and photon-assisted tunneling rather than trapping-detrapping of charge carriers from the quantum dots. In particular, a strong noise suppression effect determines the decrease of the fluctuation intensity as the voltage increases in the negative differential photoconductivity region of the I-V characteristics. The noise suppression mechanism acts in the dark and under irradiation. The noise intensity decreases consistently with the occurrence of the nonlinear differential photoconductivity effect.