Monolithic circuit is ‘a milestone for low-cost, high-resolution broadband and hyperspectral imaging systems’
Researchers at the Institute of Photonic Sciences (IFCO) in Spain, have built the first monolithic device to combine a CMOS integrated circuit with graphene and quantum dots (QDs).
The chip, which is made up of hundreds of thousands of photodetectors based on graphene and PbS colloidal QDs, functions as a digital camera that is sensitive to UV, visible and infrared light at the same time.
The study was published in Nature Photonics.
The graphene-QD hyperspectral, image sensor was fabricated by taking PbS colloidal quantum dots, depositing them onto the CVD graphene and subsequently depositing this hybrid system onto a CMOS wafer with image sensor dies and a read-out circuit.
The work was carried out by ICFO researchers Stijn Goossens, Gabriele Navickaite, Carles Monasterio, Schuchi Gupta, Juan Jose Piqueras, Raul Perez, Gregory Burwell, Ivan Nitkitsky, Tania Lasanta, Teresa Galan, Eric Puma, and led by ICREA (Catalan Institution for Research and Advanced Studies) professors Frank Koppens and Gerasimos Konstantatos, in collaboration with the company Graphenea.
“No complex material processing or growth processes were required to achieve this graphene-quantum dot CMOS image sensor. It proved easy and cheap to fabricate at room temperature and under ambient conditions, which signifies a considerable decrease in production costs. Even more, because of its properties, it can be easily integrated on flexible substrates as well as CMOS-type integrated circuits,” said Stijn Goossens.
The team engineered the QDs to extend to the short infrared range of the spectrum (1100-1900nm), to a point where it was possible to demonstrate and detect the night glow of the atmosphere on a dark and clear sky enabling passive night vision.
“This work shows that this class of phototransistors may be the way to go for high sensitivity, low-cost, infrared image sensors operating at room temperature. addressing the huge infrared market that is currently thirsty for cheap technologies,” said Gerasimos Konstantatos
“The development of this monolithic CMOS-based image sensor represents a milestone for low-cost, high-resolution broadband and hyperspectral imaging systems,” said Frank Koppens.
The researchers think that this kind of technology could potentially be used in applications such as night vision, food inspection, fire control, and vision under extreme weather conditions, to name a few.
This project is currently incubating in ICFO’s Launchpad. The team is working with the institute’s tech transfer professionals to bring this breakthrough along with its full patent portfolio of imaging and sensing technologies to the market.
The research has been partially supported by the European Graphene Flagship, European Research Council, the Government of Catalonia, Fundaciù Cellex and the Severo Ochoa Excellence program of the Government of Spain.