Bio-inspired short-wave infrared single photon detectors and imagers with high gain, suppressed noise and low jitter.

摘要

Novel bio-inspired infrared single photon detectors and imagers were developed towards operation in short-wave infrared domain from 0.95 to 1.65 mum. They were designed to exploit the properties of the type-II band alignment in InP/GaAsSb/InGaAs structure to achieve higher internal amplification, lower noise levels and high speed operation.;The short-wave infrared (SWIR) detectors play an important role in many modern world applications spanning diverse fields. From the optical-to-electrical converters for telecommunication wavelengths in the internet backbone to the non-invasive medical imaging methods; from the military night-vision systems to non-destructive material inspection for homeland security, the SWIR detectors present an irreplaceable element in many essential technologies. In addition to these existing applications, emerging applications like quantum cryptography/computing, and quantum ghost imaging demand high-performance SWIR detectors.;To overcome the limitations of existing technologies, a novel SWIR single photon detector was created. Conceptually inspired by the single photon detection mechanism in the rod cells of human visual system, the nano-injection detector uses an engineered geometry in a material system with type-II band alignment to achieve high efficiency photodetection.;The layer structure and geometry of nano-injection detectors were designed and optimized with a three-dimensional nonlinear finite element method simulation. Fabricated high gain nano-injection detectors showed stable gain values reaching 10,000 at at 1 V and room temperature. Sub-Poissonian shot noise levels were achieved with Fano factors as low as 0.55. High-speed nano-injection detectors with bandwidths exceeding several gigahertz exhibited ultra-low jitter values of ∼14 ps at room temperature, outperforming the best SWIR photon detectors with internal gain at room temperature. The isolated nano-injection detectors simultaneously show high gain values exceeding 1,200 (i.e. 1500 A/W) with high speed response, where the rise time was 900 ps and the fall time was 33 ns.;Arrays of nano-injection detectors were hybridized to form focal plane array infrared cameras with 320 by 240 pixels. The unpassivated nano-injection imagers show responsivity values in excess of 2,500 A/W. Measured imager noise was 28 electrons at a frame rate of 1,950 frames/sec. Compared to commercial SWIR imagers, the imagers show two orders of magnitude improved signal-to-noise ratio at thermoelectric cooling temperatures.