Design of a top mirror for the n-GaAs homojunction far-infrared/terahertz detectors

摘要

The top mirror of the resonant cavity enhanced homojunction interfacial workfunction internal photoemission (HIWIP) far-infrared (FIR)/terahertz (THz) detector is investigated. Aiming at an existing half-optimized n-GaAs HIWIP FIR/THz detector, two designs of the top mirror are investigated to increase the quantum efficiency. The genuine or equivalent single layer is proved to be unqualified as the top mirror. A design based on the two-dimensional (2D) periodical reversed pyramidal structure of intrinsic GaAs is proposed as the top mirror. The resulted quantum efficiency can be as high as 29.0%. Some elementary thoughts and a tentative fabricating solution of this 2D periodical reversed pyramidal intrinsic GaAs top mirror are suggested. The designing ideas of this kind of top mirror may also be applied to other FIR/THz devices for reference.