Observation of Non-Gaussian and Generation-Recombination Noise in n-Type GaAs/AlGaAs Multiple Quantum Wells

The time trace and the noise spectrum of the dark current are measured to probe the non-Gaussian properties and the generation-recombination noise in n-type GaAs/AlGaAs quantum well infrared photodetectors. We observed that time-dependent random telegraph signals showed a non-Gaussian two-level random fluctuation of the current amplitude arising from trapping and detrapping of carriers by a quantum well. A change in the carrier lifetime, which corresponds to capture in a well, is also observed at low bias by measuring the low-frequency noise spectrum. We investigated a relation between the two-level random fluctuation and the carrier lifetime or the capture probability.