Asymmetry in the dark current low frequency noise characteristics of B–B and B–C quantum well infrared photodetectors from 10 to 80 K

We present experimental results demonstrating the significant effect that the type of intersubband transition has on the dark current noise of quantum well infrared photodetectors containing 32 Si-doped GaAs quantum wells separated by ∼350 Å thick AlxGa1−xAs barriers. The experimentally observed asymmetry in the noise characteristics is similar but larger than the asymmetry between dark currents under forward and reverse bias voltages. We are able to control the ratio between the components of the dark current by biasing with constant current and varying the temperature over an extended range well below the intended operational point. Our results indicate a clear relationship between the excessive low-frequency generation-recombination noise and the thermally assisted tunneling component of the dark current. We have also found indications that the excessive 1/f like noise component can be related to the tunneling process in direct well-to-well tunneling and to thermally assisted tunneling dark current mechanisms.