Nanoscale Hybrid Electronic Systems

We systematically investigate the impact of granularity in CVD graphene films by performing Raman mapping and electrical characterization of single (SD) and multi domain (MD) graphene. In order to elucidate the quality of the graphene film, we study its regional variations using large area Raman mapping and compare the G and 2D peak positions of as-transferred Chemical Vapor Deposited (CVD) graphene on SiO2 substrate. We find a similar upshift in wavenumber in both SD and MD graphene in comparison to freshly exfoliated graphene. In our case, doping could play the dominant role behind the observation of such upshifts rather than the influence due to strain. Interestingly, the impact of the polymer assisted wet transfer process is the same in both the CVD graphene types. The electrical characterization shows that SD graphene exhibits a substantially higher (a factor 5) field-effect mobility when compared to MD graphene. We attribute the low sheet resistance and mobility enhancement to a decrease in charge carrier scattering thanks to a reduction of the number of grain boundaries and defects in SD graphene.

Figure Large area Raman scans of D, G and 2D bands (a-c, g-i) and peak position-histograms of SD (d-f) and MD (j-l) graphene. The average peak positions are marked with black dotted lines for D, G and 2D bands. Features in the large area scans are marked using white arrows. Scale bars: 4 µm (SD) and 2 µm (MD)

Comparative study of single and multi domain CVD graphene using large area Raman mapping and electrical transport characterization
Kishan Thodkar, Maria El Abbassi, Felix Lüönd, Frédéric Overney, Christian Schönenberger, Blaise Jeanneret and Michel Calame
pss-RRL (2016), DOI: 10.1002/pssr.201600211

Michel Calame, staff member at the Swiss Nanoscience Institute and the Department of Physics at the University of Basel, has accepted to lead a laboratory at the Empa (Swiss Federal Laboratories for Materials Science and Technology) with a new focus on “Nanoscale Transport Phenomena”, starting Oct. 1st, 2016. The activities of the group in Basel continue and will be progressively transferred to the Empa. The whole Nanoscale Hybrid Electronic Systems group will be integrated in the Empa lab and based in Dübendorf from August 2017 on.

Announcement at Empa: link.

New address
Michel Calame
Empa
Swiss Federal Laboratories for Materials Science and Technology
Ueberlandstrasse 129
CH-8600 Dübendorf
Tel: +41 58 765 4260
michel.calame@empa.ch

For administrative matters
Silvia Eppenberger (Mo-Th)
Silvia.Eppenberger@empa.ch
+41 58 765 4272

Béatrice Spoerri (Tu, Fr):
Beatrice.Spoerri@empa.ch
+41 58 765 4407

At the 8th International Conference on Molecular Electronics “Elecmol–2016” (August 22−26, Université Pierre et Marie Curie, Paris):

• Anton gave a talk “Controlled formation of organometallic molecular junctions in liquid environment”; 
• Jan presented a poster “Investigation of Electron Transport in Molecular and Optoelectronic Nanojunctions” – won a poster prize!
• Maria presented a poster “Graphene molecular junctions”.

Last week, we enjoyed a nice mountain tour in the Susten region together with the Nanoelectronics group. Thanks to Clevin & Simon for organizing it!

Abendliche Tea Party mit Physik beim Spielzeugmuseum in Riehen.

Anlässlich der Finissage der Ausstellung „Merk- und merkerwürdig Im Wunderland”, fand am Sonntag 10. July eine grosse Tea-Party im Spielzeumuseum statt. Jüngere und ältere konnten sich da auch von physikalischen Experimenten verblüffen lassen.

Am 21. Mai 2016 fand in Gelterkinden die wissenschaftliche Publikumsausstellung Nano- und Quantenwelten in Gelterkinden statt. Mit vereinten Kräften haben es das Departement Physik, das Swiss Nanoscience Institute (SNI) und die Gemeinde Gelterkinden geschaff t, in kürzester Zeit diesen Aktionstag gemeinsam zu realisieren. Ziel war es, Transparenz zu leben sowie das gegenseitige Verständnis und die Wertschätzung zwischen Stadt und Land sowie Universität und Gesellschaft zu fördern. Dieser vereinte Eff ort resultierte in einem grossen Erfolg: Über 800 Besucherinnen und Besucher, Gross und Klein, fanden trotz Traumwetter an einem Samstag den Weg in die Mehrzweckhalle in Gelterkinden, wo sie sich an den verschiedenen Ständen, Vorträgen und sonstigen Aktivitäten über den neusten Stand der Physikforschung informieren und vergnügen konnten. Es war inspirierend und motivierend zu sehen, auf wie viel Neugier, Interesse und Fragen unsere Lehr- und Forschungsaktivitäten in der Bevölkerung gestossen sind.

Source: Universität Basel “Uniintern” magazine, 01/2016 https://www.unibas.ch/de/Mitarbeitendenportal/Aktuell/Mitarbeitendenmagazin-uniintern.html

The detection of biomarkers at very low concentration and low cost is increasinglyimportant for clinical diagnosis. Moreover, monitoring affinities for receptor-antagonist interactions by time-resolved measurements is crucial for drug discovery and development. Biosensors based on ion-sensitive field-effect transistors (BioFETs) are promising candidates for being integrated into CMOS structures and cost-effective production. The detection of DNA and proteins with silicon nanowires has been successfully demonstrated using high affinity systems such as the biotin-streptavidin interaction. Here, we show the time-resolved label-free detection of the interaction of the bacterial FimH lectin with an immobilized mannose ligand on gold-coated silicon nanoribbon BioFETs. By comparing our results with a commercial state of the art surface plasmon resonance system, additional surface effects become visible when using this charge based detection method. Furthermore, we demonstrate the effect of sensor area on signal-to-noise ratio and estimate the theoretical limit of detection.

Label-Free FimH Protein Interaction Analysis Using Silicon Nanoribbon BioFETs
Mathias Wipf, Ralph Stoop, Giulio Navarra, Said Rabbani, Beat Ernst, Kristine Bedner, Christian Schönenberger, Michel Calame
ACS Sensors,  1(6), 781-789 (2016), DOI:10.1021/acssensors.6b00089

On May 4th, during the plenary session of the EMRS 2016 Spring Meeting (Lille, France), Kishan Thodkar was awarded with the first prize in the E-MRS Reach.Out! competition. 

Reach.Out! is a science communication competition that aims to engage the members of the European Materials Science community who have designed, organised and implemented a public outreach activity in the EU. This outreach activity must be related to Advanced Materials and its main aim must have been to uncover, to the non-specialists, one or more of the following aspects of work within this field: its applications, its impact on the creation of sustainable societies, its impact on the economy, the people behind the scenes, the complexity of the work done, and of course, possible controversies etc.

Anton talked about “Self-assembled nanoparticle arrays with graphene contacts” (talk J.VI.10) at Symposium J;

Kishan reported about “Characterization of HMDS-treated CVD Graphene” (Y.15.32) during the poster session of Symposium Y;

and Michel reported about “Si nanoribbon transistors for chemical and biochemical sensing” (talk O.4.1) at Symposium O.