Heterojunction interfacial workfunction internal photoemission detectors for use at 8-20 μm

Heterojunction interfacial workfunction internal photoemission (HEIWIP) detectors have already been demonstrated for use in the FIR range with cutoff wavelengths λ_c up to 85 μm. An interesting feature of these detectors is their strong response in the 8-20 μm range. Initial results are reported on HEIWIP detectors operating in the 8-20 μm range. The unoptimised detectors had a peak responsivity of 1.8 A/W at 15.2 μm at 4.2 K. HEIWIPs could be an alternative to already available detectors especially when optimised for higher temperatures. λ_c can be tailored by changing the Al concentration in the barrier. Responsivity of HEIWIPs can be selectively optimised by using the cavity mechanism and adjusting the Al fraction. It should also be possible to enhance the responsivity by changing the doping concentrations of the detectors.