Quantum Dots for Thermal Infrared Detection
Guyot-Sionnest Philippe a
Materials for Sustainable Development Conference (MATSUS)
Proceedings of nanoGe September Meeting 2015 (NFM15)
Santiago de Compostela, Spain, 2015 September 6th - 15th
Invited Speaker, Guyot-Sionnest Philippe, presentation 059
Publication date: 8th June 2015

Most research in the colloidal quantum dot community is justified by LED and PV technology, trying to improve efficiency percentile by percentile, notwithstanding issues of long term viability and large scale processing. These are highly competitive topics where there are already moderate to low cost, high volume solutions and the enormous scale of quantum dots research in those fields is therefore questionable. In contrast, Thermal infrared imaging is a high cost small volume application. The current cheapest technology uses microbolometers. These are made with conventional lithography and can be rather cheap, plus they operate at room temperature and require little power. However, their sensitivity is 1 to 2 orders of magnitude below the background limit and their response frequency is low, of the order of 10Hz. For high sensitivity and high speed, epitaxial semiconductors such as HgCdTe or InSb are used. However, these are expensive materials to fabricate, moreover they require cryogenic cooling because of the thermal generation of carriers and the fast recombination, by Auger, at moderate temperatures. Raising the operating temperature to 300K would create major opportunity for semiconductor infrared imaging. Colloidal quantum dots are a potential cheap and better alternative where the core is free of high frequency infrared vibrations but can lead to widely tunable electronic infrared transitions. Furthermore, Auger relaxation is much reduced in quantum dots at comparable carrier density. After fundamental studies of infrared interband or intraband relaxation, Auger relaxation, doping and electronic transport, we demonstrated that QD devices show background limited infrared detection, and the present challenges are to increase the operation temperature and spectral range, along with more practical issues of pixel uniformity, lifetime etc. I will present results on interband detection between 3 and 12 microns, using photoconductive or photovoltaic modes. For the first time in the 30 years of colloidal nanomaterial history, the intraband transition was also specifically used.



© FUNDACIO DE LA COMUNITAT VALENCIANA SCITO
We use our own and third party cookies for analysing and measuring usage of our website to improve our services. If you continue browsing, we consider accepting its use. You can check our Cookies Policy in which you will also find how to configure your web browser for the use of cookies. More info