Quantum Interband Cascade Superlattice Light-Emitting Diodes For Environmental And Health Sensing (Sensors Europe 2019)

The QuiC SLED light emitting diode and its photodiode counterpart, the PDQ, use InAs-GaSb p-i-n superlattices for emission and detection, cascaded with tunnel junctions. Variable-period superlattices form the carrier injectors and separate-confinement heterostructures. The superlattices mitigate Auger recombination losses; weakly-coupled dielectric buttes enhance light extraction, and composite metal-mesh electrodes aid current spreading. The first example of the platform, emitting at 4.25 µm and aligned with carbon dioxide absorption in the MWIR band, is rated at 2 mW in pulse mode at room temperature. Emitting superlattices can cover approximately 3 µm to 12 µm wavelengths. Prominent sensing applications for this class of devices, including personal air quality, environmental, health, and IoT sensing, rely on short-pulse, low-duty cycle measurements to reduce system power requirements for long battery life. An important target is for the LEDs typically to consume less than a few microjoules per measurement pulse. Within this context, the optimal QuiC SLED-PDQ properties are defined by the needs of the product stack, which starts with these mid-IR devices and extends through the analog front end chips and signal processing chips, to the application algorithms and user interface.

Dr. Miller co-founded the company in 2000 and has served full-time since 2011. Previously, Dr. Miller's research and teaching in engineering and physics centered on semiconductor device design, fabrication, and applications, with contributions in quantum nanostructures for optical and electrical devices, vacuum electronics, and terahertz technologies.

Terahertz Device Corp had developed unique mid-IR LEDs to serve the appetite of the internet-of-things (IoT) for high-volume, inexpensive, low-power optical sensor nodes for many unmet needs in environmental and health sensing. These QuiC SLEDs™ (quantum interband cascade superlattice light emitting diodes) bring the wavelengths and performance to make these billion-node applications possible. The mid-IR, spanning roughly 3-12 µm wavelengths, holds a wealth of molecular fingerprint signatures for LED-based sensing for many applications including smart buildings and smart homes, the oil and gas production and distribution infrastructure, wearable and mobile device makers, automobile clean air cabins, and many more.