AlGaAs emitter/GaAs barrier terahertz detector with a 2.3 THz threshold

摘要

A heterojunction interfacial work function internal photoemission (HEIWIP) detector with a threshold frequency (f_0) of 2.3 THz (λ_0=128 μm) is demonstrated. The threshold limit of ～3.3 THz (92 μm) due to the Al fraction being limited to ～0.005, in order to avoid control and transition from alloy to isoelectronic doping behavior, was surpassed using AIGaAs emitters and GaAs barriers. The peak values of responsivity, quantum efficiency, and the specific detectivity at 9.6 THz and 4.8 K for a bias field of 2.0 kV/cm are 7.3 A/W, 29%, 5.3 X 10~(11) Jones, respectively. The background-limited infrared photodetector temperature of 20 K with a 60° field of view was observed for a bias field of 0.15 kV/cm. The f_0 could be further reduced toward ～1 THz regime (～300 μm) by adjusting the Al fraction to offset the effect of residual doping, and/or lowering the residual doping in the barrier, effectively lowering the band bending.