Resonant Cavity Enhanced Photodiodes in the Short-Wave Infrared for Spectroscopic Detection

Abstract

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.

Solid-state micro-spectrometer based on a linear array of infrared resonant-cavity-enhanced photodetectors

“…We have already demonstrated RCE-PDs between 2.2 µm -7.8 µm using a range of III-Sb absorbers and T2SLs. [1][2][3][4][5] In theory, III-Sb RCE-PDs could be created operating between 1.5 and ~12 µm using GaSb, InGaAsSb, InAsSb and InAsSb-InAs T2SLs. This spectral range covers the SWIR, MWIR and LWIR containing absorption fingerprints in Figure 6.…”

InGaAsSb for cut-off tuned SWIR detectors

“…It has a host of applications including fiber optics, 10 thermophotovoltaic cells, 11, 12 lasers, 13,14 infrared light-emitting diodes, 15,16 and infrared photodetectors. 1,17,18 In order to design and develop optimal structures, a firm knowledge basis of various material properties and device performance has to be established. Studies conducted thus far have been largely focused on higher alloy fractions 19,20 with little to no work done on dilute alloys.…”

Development and application of quasi-planar InGaAsSb p-B-n devices for spectroscopic sensing

“…InGaAsSb lattice matched to GaSb can have a cut-off wavelength up to 4.9 μm, which extends beyond the binary GaSb which is limited to a cut-off of 1.7 μm 1 . Within the InGaAsSb cut-off range are the absorption fingerprints of substances such as glucose 2 , acetone 3 and CO2 4 , making this material prime for high impact applications. GaSb is rapidly becoming the dominant substrate for detectors in the mid and longwave infrared, however to detect between 1.7 μm and 2.6 μm, lattice mismatched InGaAs photodiodes grown on InP 5 are commonly used.…”