Far Infrared Heterodyne Detection with Gallium Doped Germanium Photoconductors

摘要

This contract has been directed at the examination of the bandwidth and sensitivity of semiconducting heterodyne detectors for far infrared radiation (FIR). Germanium detectors variously doped with gallium have been of prime interest. However, HeCdTe detectors have also been tested. While efforts to find good FIR heterodyne detectors have been slow, towards the end of the contract period substantial success was achieved and measurements have continued even past the contract period to round out what we regard as important quantitative measurements of improved detection. We have measured faster more responsive detectors and have reduced our system temperature. We have also seen for the first time, a change in detector bandwidth with bias voltage. We believe we have proceeded in the correct direction in detector fabrication and doping levels to produce faster detectors while retaining high responsivity.