Low Excess Noise, High Quantum Efficiency Avalanche Photodiodes for Beyond 2 {\mu}m Wavelength Detection

TL;DR

This paper presents a novel InGaAs/GaAsSb APD with high gain, low excess noise, and high quantum efficiency at room temperature, suitable for greenhouse gas detection beyond 2 μm, offering a manufacturable alternative to HgCdTe detectors.

Contribution

The development of a high-performance, manufacturable InGaAs/GaAsSb APD with exceptional sensitivity and low noise for greenhouse gas sensing beyond 2 μm.

Findings

Achieved a room temperature gain of 178.

Maximum external quantum efficiency of 3560%.

Excess noise factor below 2 at gain less than 20.

Abstract

The increasing concentration of greenhouse gases, notably CH4 and CO2, has fueled global temperature increases, intensifying concerns regarding the prevailing climate crisis. Effectively monitoring these gases demands a detector spanning the extended short-wavelength infrared (~2.4 {\mu}m) range, covering wavelengths of CH4 (1.65 {\mu}m) and CO2 (2.05 {\mu}m). The state-of-the-art HgCdTe avalanche photodetectors (APDs) offer exceptional performance metrics, including high gain (M) and low excess noise (F). However, their widespread adoption is hindered by inherent challenges such as manufacturability, reproducibility, and cost factors. Moreover, their reliance on cryogenic cooling adds to the cost, size, weight, and power of the system. We have demonstrated a linear mode APD combining an InGaAs/GaAsSb type-II superlattice absorber and an AlGaAsSb multiplier lattice matched to InP substrates. This APD has demonstrated a room temperature M of 178, a maximum measurable external quantum efficiency of 3560 % at 2 {\mu}m, an extremely low excess noise (F < 2 at M < 20), and a small temperature coefficient of breakdown (7.58 mV/K {\mu}m). Such a high performance APD with manufacturable semiconductor materials could lead to a rapid transition to a commercial III-V foundry, holding the promise of revolutionizing high-sensitivity receivers for greenhouse gas monitoring.