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 t he type of intersubband transition has on the dark current noise of quantum well infrared photodetectors containing 32 Si-doped GaAs quantum wells sep arated by similar to 350 Angstrom thick AlxGa1-xAs barriers. The experiment ally observed asymmetry in the noise characteristics is similar but larger than the asymmetry between dark currents under forward and reverse bias vol tages. We are able to control the ratio between the components of the dark current by biasing with constant current and varying the temperature over a n extended range well below the intended operational point. Our results ind icate a clear relationship between the excessive low-frequency generation-r ecombination noise and the thermally assisted tunneling component of the da rk current. We have also found indications that the excessive 1/f like nois e component can be related to the tunneling process in direct well-to-well tunneling and to thermally assisted tunneling dark current mechanisms. (C) 2000 American Institute of Physics. [S0021-8979(00)05105-7].