The design, fabrication and characterization of resonant cavity enhanced photodiodes for the short-wave infrared has been investigated. An InGaAsSb absorber and AlGaSb barrier were used in an nBn structure, within a Fabry-Perot cavity bounded by AlAsSb/GaSb DBR mirrors. The resonant cavity design produced a narrow response at 2.25 µm, with a FWHM of ∼ 26 nm and peak responsivity of 0.9 A/W . The photodiodes exhibited high specific detectivities and low leakage currents at 300 K -5 × 10 10 cmHz 1/2 W −1 and 0.2 mAcm −2 respectively, with an applied bias voltage of −100 mV. A maximum specific detectivity of 1 × 10 11 cmHz 1/2 W −1 was achieved at 275 K and the detector continued to perform well at high temperatures -at 350 K the peak specific detectivity was 3×10 9 cmHz 1/2 W −1 . The narrow resonant response of these detectors make them suitable for spectroscopic sensing, demonstrated by measurements of glucose concentrations in water. Concentrations as low as 1 % were discriminated, limited only by the associated electronic systems.

t q ratio and the variation in transport mobility with carrier density cannot be explained by reasonable levels of background impurities or well width fluctuations. Thus, there is at least one additional scattering mechanism unaccounted for, most likely arising from structural defects.

No abstract

No abstract

No abstract