Strong enhancement of responsivity and tunability of THz quantum-well photodetectors by magnetic field

Here we report an experimental study on the responsivity and tunability of QWIP THz photodetector under high magnetic field (B). A set of QWIP devices had been studied under magnetic field, the response peaks (lambdap) are 7.1, 5.4 and 3.2 THz at zero magnetic field. Based on the responsivity values at zero magnetic field² (in the range of 0.4 to 1.0 A/W), the responsivity under magnetic field reaches about 10 A/W, larger than that achieved in mid-infrared QWIPs³. While the maximum relative tuning band (deltalambdap/lambdap) is about 90%. For example, by adjust the magnetic field from zero to 10 Tesla, the response peaks can be tuned from 3.2 THz to 5.4 THz. This large tunability will be very useful for the THz spectroscopy application.