Low-noise high-temperature AlInAsSb/GaSb avalanche photodiodes for 2-μm applications

Sensitive photodetectors that operate at a wavelength of 2 μm are required for applications in sensing and imaging but state-of-the-art devices are severely limited by high dark current density ( J dark ). The narrow-bandgap materials required for mid-infrared (2–5 µm) detection are plagued by carrier recombination and band-to-band tunnelling; as a result, detectors must be operated at cryogenic temperatures. HgCdTe is currently the most commonly used materials system for these applications and has achieved J dark = 3 × 10 −4 A cm – 2 at a gain of 10 while operating at 125 K. Here, we report the details and results for avalanche photodiodes for 2-μm detection based on a separate absorption, charge, and multiplication design in the Al x In 1– x As y Sb 1– y materials system. We achieve comparable J dark between 200–220 K and demonstrate very low excess noise ( k ≈ 0.01) and gain >100 at room temperature. Such avalanche photodiodes could prove useful for receivers for eye-safe light imaging, detection and ranging. Highly sensitive avalanche photodiodes that operate at near-infrared wavelengths of up to 2 μm could prove useful for eye-safe light imaging, detection and ranging, and other applications.