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Christian Buhl Sørensen: Broadband Graphene-Quantum Dot Optical Sensor

posted 6 Jul 2016, 02:18 by info admin
Christian Buhl Sørensen(1), Jens Larsen Lausen(1), Bjarke Egede Jensen(1,2), Rene Lynge Eriksen(3), Bjarke Jørgensen(1)
(1) Newtec Engineering; (2) Aarhus University; (3) ITI, University of Southern Denmark

The field of optical sensing has experienced a resurgence following the explosive interest in 2D materials, such as graphene. The optical ranges of near infrared (NIR) and mid infrared (MIR) are of special interest, as the existing sensors are either expensive, cumbersome to use, or has low sensitivities.

At Newtec Engineering A/S we have fabricated and investigated sensors based on FET structures,
with graphene and quantum dots as conduction layer and gain medium respectively. The substrates are made using standard photolithography procedures, the graphene is grown with high temperature CVD and the quantum dots are synthesized by liquid phase supersaturation; everything in-house.

We have demonstrated photo response with a responsivity and a temporal bandwidth usable for real life application. Promising results have been obtained in a very short time span, indicative of a robust principle for sensing devices. The immediate opportunities for optimization include quantum dot film post-processing, graphene quality and improved charge transfer.

This platform holds great promise for sensing from visible to mid infrared ranges with a consistently high sensitivity, simple operation and low price. The platform may also be used for other sensor configurations. Furthermore, it is compatible with contemporary integrated circuit- and CMOS technology which, in time, will enable broadband image sensors.

Christian Buhl Sørensen and Jens Larsen Lausen are currently employed as research and development engineers at Newtec Engineering, in Odense. They both hold a recent masters degree in optics and nanotechnology, from the University of Southern Denmark. Jens' extensive knowledge in nanofabrication and characterization complements Christians skills with electronic measurement techniques and optics. 

Newtec Engineering is developing the next generation of weighing and grading machines, for fruits and produce. The research and development department furthermore covers competencies in general physics, electronics, laser physics, chemistry and biology.