Supervisor : Emmanuel Lhuillier
Contact : el@insp.jussieu.fr
Funding : Sorbonne Université - CNRS
keywords : Experimental and Internship M2
Gratification : Oui
Team(s) internship page(s) : Chemical Physics and Dynamics of Surfaces  
Internship description

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Nanocrystals are semiconductor nanoparticles, which optical fetaures can easily be tuned from UV to the THz range. So far most pof the effort have been focused on the visible wavelength where nanocrystals have reached a commercial status for example as light down-converter into display. Another application is their use as absorbing and light emitting material in the infrared range [a]. Nnaocrystals can be transformed into photoconductive thin films. INSP group have recently the hability to build camera [2] from such film and the latter are very promissing to design a new generation of cost effective device in the infrared.

Our early effort have been focused on the short wave infrared (2.5 µm) [3] In this project we target to explore much longer wavelength (ie >10 µm and possibly up to 100 µm) [4]. Three startegies will be explores to obtain absorption at such wavelength. The most naive approach is to grow larger particle to reduce the quantum confinment, but this needs to be done while preserving the particle colloidal stability. This is critical to later build uniform and pinhole free film. Alternatively particle can be doped to achieve intraband absorption. Finally, core shell strcture with type II band alignement may also appears as a strategy to reduce the eneregy of the optical transistion. The latter method also present the benefit to duissociate the electrion hole pair whicc is a critical step for their later use into photoconductive device.

The intern will be in charge of the growth of these particles and their structural characterization (TEM, XRD). Then he will be involved in the device characterization (clean room and glove box prpocessing) and finally he will takes part to the device characterization using cryogenic environment

Keywords: nanocrystals, device, infrared

Background : the applicant will have a background in semiconductor or in nanopartcile synthesis. skill in clean room or electrical measurement will be a plus but are not mandatory. The group being international, the applicant must speak english

 

References

[1] Mercury Chalcogenides Quantum Dots: a Material Perspective for Device Integration, C. Gréboval, et al Chem Rev 121, 3627 (2021)

[2] Photoconductive focal plane array based on HgTe quantum dots for fast and cost-effective short-wave infrared imaging, C. Gréboval et al, Nanoscale 14, 9359 (2022)

[3] Seeded growth of HgTe nanocrystals for shape control and their use for narrow infrared electroluminescence, Y. Prado, et al, Chem Mater 33, 2054 (2021)

[4] Terahertz HgTe nanocrystals: beyond confinement, N. Goubetet al, J. Am. Chem. Soc. 140, 5053 (2018).