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

Bainbridge, Andrew and Mamic, Katarina and Hanks, Laura and Al-Saymari, Furat and Craig, Adam and Marshall, Andrew (2020) Resonant Cavity Enhanced Photodiodes in the Short-Wave Infrared for Spectroscopic Detection. IEEE Photonics Technology Letters, 32 (21). pp. 1369-1372. ISSN 1041-1135

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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^1/2W^−1 and 0.2 mAcm^−2 respectively, with an applied bias voltage of −100 mV. A maximum specific detectivity of 1×10^11 cmHz^1/2W^−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^1/2W^−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.