Project TESEER (2008-2012)
"Thermoelectric/thermoionic micro Energy Source Enhanced by Electromagnetic Radiation"
Grant : EADS Foundation - 2007 call
Objectives
Results
Publications
Project Goals
In this project we study the photo-thermal conversion behavior of a ligth absorbing surface made on silicon with the prospect of producing a hot spot intended to integrate a thermoelectric energy harvester. The thermoelectric elements will consist in the vertical superlattices studied in the project COFISIS. In order to fuel it by solar radiation, the optimization of the hot spot is crucial. To this end, we are developing a light-absorbing silicon layer with extremely low reflectivity obtained by cryogenic Deep Reactive Ion Etching (DRIE), so as to maximize heating of the hot spot under the effect of electromagnetic (EM) radiation in the visible and near-infrared ranges.The obtained material is known as black silicon, a material consisting of dense (sub)-micrometer cones which lead to multiple reflections of incident photons and hence to light trapping and absorption. An air cavity etched on the back side thermally insulates the hot spot, which is heated by incident light focused by a microlens.
Sketch of the target device.
Results
Conical black silicon wafer was fabricated by DRIE under cryogenic temperatures with diameter of 350 nm, height of 1.4 µm and periodicity of 570 nm. The cones are fabricated in a collective manner over the whole wafer area. This structure presents excellent antireflective behavior over the 400 – 950 nm spectral range with a reflectance ~ 1% in the visible range. This reflectance level is among the best published in the literature for plasma-etched black silicon.
SEM image of Black Silicon obtained by a cryogenic DRIE process at Université Paris-Est / ESIEE Paris.
Measured reflectance spectra of black silicon under normal incidence.
Related publications
Journals
"On the optical and morphological
properties of microstructured Black Silicon obtained by cryogenic-enhanced
plasma reactive ion etching", K. N. Nguyen, P. Basset, F. Marty, Y.
Leprince-Wang and T. Bourouina, AIP
Journal of Applied Physics, 113, 194903 (2013)
- “Study of black silicon obtained by cryogenic plasma etching: approach
to achieve the hot spot of a thermoelectric energy harvester”, K.
N. Nguyen, D. Abi-Saab, P. Basset, E. Richalot, M. Malak, N. Pavy, F.
Flourens, F. Marty, D. Angelescu and Y. Leprince-Wang et T. Bourouina, Microsystem Technologies, vol. 18, pp. 1807–14, 2012
Conferences
- “Black silicon with sub-percent reflectivity: influence of the 3D texturization geometry”, K. N. Nguyen, D. Abi-Saab, P. Basset, E. Richalot, F. Marty, D. Angelescu, Y. Leprince-Wang, T. Bourouina, , Proceeding of the 16th int. Conf. on Solid-State Sensors, Actuators and Microsystems (Transducers’11), Beijing, China, 2011
- "Study of Black Silicon Obtained by Deep Reactive Ion Etching – Approach to Achieving the Hot Spot of a Thermoelectric Energy Harvester", K.N Nguyen, D.Abi-Saab, M. Malak, P. Basset, E. Richalot, N. Pavy, F. Flourens, F. Marty, D. Angelescu, Y. Leprince-Wang, T.Bourouina, Proceeding of the 13th symposium on Design, Test, Integration and Packaging Conference (DTIP’11), Aix en Provence, France, 2011
- “On the Use of Black Silicon Obtained by Reactive Ion Etching
as the Hot Spot of a Thermoelectric Generator Heated by Electromagnetic
Radiation”, K. Ngoc Nguyen, P. Basset
and E. Richalot, Proceeding of the 6th Conference on Ph.D. Research in Microelectronics & Electronics
(PRIME’10),