Integrated Multi-Color Light Emitting Device Made with Hybrid Crystal Structure

Sang Choi,
NASA Langley Research Center;
Yeonjoon Park,
National Institute of Aerospace (NIA)Hampton, VA

Today's LEDs are built with many compound semiconductors with type-I direct bandgap energies of two different crystal structures. While red, orange, yellow, and yellowish-green LEDs are commonly made with III-V semiconductor alloys of aluminum gallium indium phosphide (AlGaInP) and aluminum gallium indium arsenide (AlGaInAs) with cubic zinc-blend crystal structures, the higher-energy colors such as green, blue, purple, and ultraviolet (UV) LEDs are made with III-Nitride compound semiconductors of AlGaInN alloys with hexagonal wurtzite crystal structures. Because the atomic crystal structures are different for red LED and green/blue LEDs, the integration of these semiconductor LEDs as individual R, G, B pixels on one wafer was almost impossible.

NASA Langley Research Center has developed a process for making red, green, and blue LED device structures on the same substrate (wafer) to improve displays. The hybrid crystal LED display device comprises double-sided hetero crystal growth with a hexagonal wurtzite III-Nitride compound semiconductor on one side of c-plane sapphire media, and a cubic zinc-blended III-V or II-VI compound semiconductor on the opposite side.

“Winning first prize in the Electronics Category brings wide exposure and great opportunity for our technology. This multi-color LED will offer a new dimension to current display technology, and it is a great privilege for us to pursue with others the advancement of this technology to the marketplace.”

The c-plane sapphire media may be a bulk single crystalline c-plane sapphire wafer a thin freestanding c-plane sapphire layer or crack-and- bonded c-plane sapphire layer on any substrate. The bandgap energy and lattice constant may be engineered by changing the alloy composition within the cubic group IV, group III-V, and group II-VI semiconductors, and within the hexagonal III-Nitrides.

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HONORABLE MENTIONS

World’s First Cost-Effective Multispectral Sensor-on- Chip Solutions

Tom Griffiths, ams AG,
Austin,TX

The AS726x cost-effective, multispectral, sensor-on-chip solutions enable chip-scale spectral analysis.They bring the lab to the sample for applications from food safety and product authentication, to routine testing. The multispectral sensors employ a new fabrication technique that enables nano-optical interfer- ence filters to be deposited directly on the CMOS silicon die with extreme precision. Onboard intelligence allows the sensors to be calibrated for life.

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Portable Rapid Sensor for Detection of E. Coli in Water

Parmiss Mojir Shaibani and Amirreza Sohrabi,
Roshan Water Solutions, Edmonton,
Alberta, Canada

The early detection of pathogens in drinking water can prevent widespread life-threatening infections and catastrophic outbreaks. The VeloCensTM portable sensor detects E. coli in water in one hour. It operates by monitoring the metabolic activity of the bacterial cells and changes in the pH of the local surroundings. It can be used on-site to help decide whether water is safe to use, especially in rural areas.

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Hearo — Internet of Sound

Hakan Lidbo and Max Bjorverud,
Libido Music AB,
Stockholm, Sweden

Hearo is an Internet of Sound sys- tem, through which any object in the home can be a digital controller. It is taught to identify certain sounds from certain objects with the app; for exam- ple, the sound of a spoon on a teacup could make Spotify skip to the next song in a playlist.The sound of the object becomes a digital controller — Hearo doesn’t record the sounds or store them online, eliminating addi- tional devices.

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Environmental Sensing in the IoT with BME680

Silvia Mayer and Thomas Block,
Bosch Sensortec, Reutlingen,
Land Baden- Wurttemberg, Germany

BME680 is a tiny sensor for ambient temperature, relative humidity, barometric pressure, and gas.The sensor measures indoor air quality for applications such as smart homes and IoT for environmental sensing, as well as health monitoring, home automa- tion control, leisure and sports, and smart transportation. It enables battery-driven devices to run for up to two years without bat- tery change.

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