A surface plasmonic coupled mid-long-infrared quantum well detector

Abstract This paper presents a surface plasmon (SP)-coupled quantum well infrared detectors based on a rectangular gold patch arrays to enhance the absorption of vertically incident light in GaAs/AlGaAs quantum well structures across the mid-long-infrared band. The electric fields are analyzed by algorithm of finite difference time domain method. The device exhibits strong localized electric field enhancement in the quantum wells region. Fourier transform infrared spectroscopy measurements confirmed that the resonance wavelength peak excited by SP in the coupled device as well as the absorption wavelength of the quantum wells, which is consistent with the simulation results. The detector achieves a peak detectivity of 1.27 × 10 8 cm·Hz 1/2 W −1 at λ = 7.6 μ m under a bias voltage of 1.68 V and the temperature of 77 K. Moreover, the structure demonstrates excellent fabrication incident angle compatibility and can be well compatible with FPAs, which is favored for practical applications.