PORTEFEUILLE

The optoelectronic and nanoelectronic industries promise to bring solutions to current environmental problems by providing affordable high efficiency photovoltaics, solid-state lighting and processors. Yet, these technologies enter the every-day life slowly, partly due to the lack of enabling tools. Manufacturers struggle to improve their devices and production. To speed up the development of optoelectronics components and improve the production yield, controlling electron current at the nanometer scale becomes indispensable.

This project aimed at bringing new inspection tools to the emerging nanoelectronic and photoelectronic industries. It does so by bridging the gap between two technologies apparently very different: electron microscopy and ultrafast optics. In this respect, this project is very innovative and promising.

During this project, an ultrafast fiber optical electron source was developed and mounted within a commercial electron microscope. This new instrument was turned into a movie camera of the nanoworld, in such a way that it meets the requirements of the industry. A market study was also conducted which validates short-term to long-term market opportunities for such an instrument. The project is completed and follow up projects are running.

Electron source manufacturing and testing:
A manufacturing process for fiber-based electron sources was set up and optimized. The electron source comprises an ultrafast UV laser, an optical fiber and a photocathode. Different production methods have been tested for those electron sources. Each source prototypes were mounted for testing within a dedicated electron gun on a scanning electron microscope. Parameters as beam spot size, maximum output current and lifetime were measured. The beam spot size at sample level turned out to be independent of the production method. A thorough alignment of the electron microscope always led to a spot size of 50 nm. Much difference could be observed in the efficiency and degradation/lifetime of the source. It turned out to strongly depend on the manufacturing protocol and the quality of the material that were used. Much work has been done in order to understand the aging process. Using non-solarizing optical fibers and high-quality photocathodes could significantly reduce it.

Market study:
The participation to tradeshows and contacts with over 200 potential customers have validated short-term to long-term market opportunities for such equipment. It also led to a pipeline of potential clients interested in such an acquisition.

Follow-up projects:
A CTI/KTI project has been started in collaboration between EMPA, EPFL and Attolight in order to improve the reliability and throughput of the production process.

P. Corfdir, P. Lefebvre, L. Balet, S. Sonderegger, A. Dussaigne, T. Zhu, D. Martin, J.-D. Ganière, N. Grandjean, and B. Deveaud-Plédran. Exciton recombination dynamics in a-plane (Al,Ga)N/GaN quantum wells probed by picosecond photo and cathodoluminescence, Applied Physics 107, 043524 (2010);
N. Grandjean, E. Feltin, R. Butté, J.-F. Carlin, S. Sonderegger, B. Deveaud, and J.-D. Ganière. Growth mode induced carrier localization in InGaN/GaN quantum wells, Philosophical Magazine 87, 2067 (May 2007);
S. Sonderegger, E. Feltin, M. Merano, A. Crottini, J.-F. Carlin, R. Sachot, B. Deveaud, N. Grandjean, and J.-D. Ganière. High spatial resolution picosecond cathodoluminescence of InGaN quantum wells, Applied Physics Letters 89, 232109 (2006);
M. Merano, S. Sonderegger, A. Crottini, S. Collin, E. Pelucchi, P. Renucci, A. Malko, M. H. Baier, E. Kapon, J.-D. Ganière, and B. Deveaud. Time-resolved cathodoluminescence of InGaAs/AlGaAs tetrahedral pyramidal quantum structures, Applied Physics B 84, 343 (2006);
M. Merano, S. Sonderegger, A. Crottini, S. Collin, P. Renucci, E. Pelucchi, A. Malko, M. H. Baier, E. Kapon, B. Deveaud, and J.-D. Ganière. Probing carrier dynamics in nanostructures by picosecond cathodoluminescence, Nature 438, 479 (24 November 2005);
M. Merano, S. Collin, P. Renucci, M. Gatri, S. Sonderegger, A. Crottini, J.-D. Ganière, and B. Deveaud. High brightness picosecond electron gun, Review of Scientific Instruments 76, 085108 (2005);
S. Collin, M. Merano, M. Gatri, S. Sonderegger, P. Renucci, J.-D. Ganière, and B. Deveaud. Transverse and longitudinal space-charge-induced broadenings of ultrafast electron packets, Journal of Applied Physics 98, 094970 (2005).

Un microscope qui oberserve les electrons en mouvement, Le Temps, 03.06.2008, Auflage 46189, Seite 22;
Ils ont levé des fonds!, Le magasin des créateurs, Numéro 6, page 56;
Jetzt kann man die Nanowelt filmen, Cash, 04.02.2009, Auflage 111720, Seite 5;
Interview at the RSR, Journal de 12h30 on “Esprit d’entreprise en période de crise”, short interview with Samuel Sonderegger;
MSM - Le Mensuel de l'Industire, Octobre 2nd, 2008, page 10.