Resonant cavity enhanced GaAs/AlGaAs IR detectors

HEterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) detectors have been demonstrated with cutoff wavelengths λ c up to 92 μm. One method of increasing the response in a desired range is to employ the cavity effect to create resonant maxima. Results are reported here confirming the presence of cavity enhancements in both the absorption and the detector response of HEIWIP structures at the 3λ/4 resonance. The detectors consisted of 13, 19 and 30 Be doped GaAs emitter and undoped Al 0.02 Ga 0.98 As barrier layers. Transmission and reflection spectra for multilayer GaAs/AlGaAs IR detectors in the range 2000-100 cm -1 at room temperature are presented. Comparisons with the calculated results based on free carrier absorption and interaction with optical phonons model are reported. It is shown that the absorption can be maximized by using the resonant cavity effect. The use of the resonant cavity effect should allow the design of detectors with increased response in the desired wavelength ranges.