2015
- Dynamics of formation and electrical transport in molecular junctions
Seminar
EMPA (Dübendorf), Nov. 16, 2015. - Does molecular electronics compute ?
Seminar
Federal Office of Metrology (metas), Nov. 24, 2015. - Molecular junctions: dynamics of formation and electrical transport
Plenary talk
Science et Technologie des Systèmes pi-Conjugués (SPIC 2015), Angers, France, Oct. 12-16, 2015.
- Molecular junctions: dynamics of formation and electrical transport
Invited talk
Nanoweek 2015, Limerick, Ireland, Oct 21-22, 2015. - Formation Mechanisms and Electrical Transport: from Individual to Arrays of Molecular Junctions
Invited talk
8th International Conference on Materials for Advanced Technologies (ICMAT2015), Symposium Z: Surfaces/Interfaces Modification by Molecules, Singapore, Malaysia, June 28-July 3, 2015. - From transport mechanisms in molecular junctions to ion sensing using ISFETs
Seminar
Institute of Electronics, Microelectronics and Nanotechnology (IEMN), Lille, France, March 5, 2015.
2014
- Electromechanical structure of molecular junctions & alternative contacting strategies
Invited talk
International Workshop "Controlled charge and heat transport at the molecular scale", University of Konstanz, Germany, September 29 – October 1, 2014. - Formation and transport mechanisms in individual and self-assembled networks of molecular junctions
Invited talk
2nd Self-Assembly and Molecular Electronics conference, Aalborg, Denmark, August 27-29, 2014. - Mechanical and electronic structure of molecular junctions and alternative contacting strategies
Seminar
Walter Schottky Institut (WSI), Technische Universität München (TUM), June 24, 2014..
[Abstract]
The formation of molecular junctions (MJs) is a dynamic process [1] where the atomic details of the interface between the contact electrodes and the molecule(s) strongly influence its electronic properties. The variability of possible microscopic configurations and limited stability of the different arrangements make a detailed understanding of MJs delicate and limit their applicability as electronic and optoelectronic compounds [2]. Time-dependent and spectroscopic characterizations of these systems can thus help developing a deeper insight in the mechanisms at stake. With a Conducting Atomic Force Microscope (C-AFM), we have simultaneously investigated the electrical and mechanical properties of Au-Au and Au-molecule-Au junctions [3]. We show that scatter plots (2D histograms) are a powerful method to correlate force with conductance. Our measurements support a scenario where, in about twenty percent of the MJs formed during a breaking cycle, the molecules migrate along the metal contacts thanks to the mobility of surface atoms. Using a mechanically-controllable break junction (MCBJ) setup operated in a liquid environment, we have recorded IV characteristics and observed current rectification effects in symmetric and asymmetric molecular junctions. From a simple analytical model, we can extract basic parameters such as the electronic coupling provided by different anchor groups. The relatively fast IV acquisition rate achieved opens the possibility to follow the evolution and symmetry changes of IV traces along a single conductance plateau. We also investigated the effect of dipolar binding groups on the formation of conductance plateaus not only during opening cycles (i.e. opening and breaking of the junction) but also during closing cycles (i.e. while pushing the contacts together). An alternative approach to contact few molecules consists in using graphene electrodes. Gold, the most commonly used metal to create MJs, presents major drawbacks such as high mobility of the surface atoms, a strong screening of a backgate potential and the existence of many possible binding geometries leading to ill-defined MJ conductances. Graphene is interesting in this context as its planarity will grant an easier access for gating experiments as well as facilitate optical and scanning probe imaging. Furthermore, it can be produced at large scale through e.g. chemical vapor deposition (CVD). Using an electroburning process, we have recently demonstrated the fabrication of nanoscale gaps in graphene constrictions at high yield [4]. The electrodes formed in this way are suitable for the subsequent contacting of molecules. References 1. J. Brunner et al., Random telegraph signals in molecular junctions, submitted to J. Phys. Cond. Matt. (2014) 2. See e.g. the special issue: Does molecular electronics compute? Nat. Nanotech 8, 377 (2013); See also the review: Molecular electronics: functions and features arising from tailor-made molecules, M. Mayor, M. Calame and R. Waser, in Nanoelectronics and information technology, 3rd Ed., Wiley-VCH (2012) 3. C. Nef et al., Force-conductance correlation in individual molecular junctions, Nanotechnology, 23, 365201 (2012) 4. C. Nef, et al., High-yield fabrication of nm-size gaps in monolayer CVD graphene, Nanoscale 6, 7249 (2014)
- Emerging functionality in nanoparticles arrays
Invited talk
E-MRS Spring meeting, Lille, May 26-30, 2014..
[Abstract]
Arrays of metal nanoparticles interlinked by an organic matrix have attracted a lot of interest due to their diverse electronic and optoelectronic properties [1]. By controlling the nature of the matrix material and the interparticle distance, the electronic behavior of the nanoparticle array can be substantially tuned and controlled [1,2]. We have recently shown that nanoparticle arrays form a useful architecture to build networks of molecular junctions. Here, the nanoparticles act as electronic contacts to the molecules and a molecular functionality can be used to induce an overall functionality at the array scale. Using this approach, we have build nanoarticles arrays exhibiting for instance redox [3] and optical [4] switching behaviors. The later is made possible thanks to the excitation of surface plasmons in the nanoparticles. Thanks to this particular configuration, the molecules can easily be accessed by optical means. A resonant excitation of the molecules within the array will thus leads to a photoconductance enhancement at the array level [5]. Nanoparticle arrays thus represent an interesting architecture opening possibilities for the development of novel molecular scale electronic and optoelectronic devices. Their possible implementation as an information storage platform or even as computing networks thanks to a defect-tolerant architecture is currently under investigation [6]. References 1. M.A. Mangold et al., Nanoparticles arrays, to appear in the Springer Handbook of Nanoparticles (2014). 2. M. Calame, Molecular junctions: from tunneling to function, Chimia Int. J. Chem, 64 (6), 391-397 (2010). 3. J. Liao et al., Cyclic conductance switching in networks of redox-active molecular junctions, Nano Letters, 10 (3) , 759–764 (2010). 4. S. van der Molen et al., Light-controlled conductance switching of ordered metalmolecule- metal devices, Nano Letters, 9 , 76-80 (2009). 5. M. A. Mangold et al., Resonant Photoconductance of Molecular Junctions Formed in Gold Nanoparticle Arrays, J. Am. Chem. Soc., 133 (31) , 12185–12191 (2011). 6. G. Wendin et al., Synaptic Molecular Networks for Bio-Inspired Information Processing, Int. J. Unconv. Comp., 8 , 325-332 (2012).
- Silicon nanowire bio-chemical sensors
Invited talk
International Conference on Ultimate Integration on Silicon, 15th ed. (ULIS 2014), Sigtunahöjden, Stockholm – Sigtuna, Sweden, April 07-09, 2014.
2013
- Spectroscopic insight on electrical transport through molecular junctions
Seminar
Department of Physics, Budapest University of Technology and Economics, Budapest, Hungary, September 26, 2013. - Characterizing the electronic and mechanical structure of molecular junctions
Invited talk
CECAM Workshop "Molecular Electronics: Quo Vadis?", Bremen, Germany, March 4-8, 2013. - Electronic transport in molecular junctions and junctions networks
Seminar
École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI), France, March 28, 2013.
[Abstract]
Electronic transport in molecular junctions and junctions networks Michel Calame Department of Physics and Swiss Nanoscience Institute, University of Basel, Switzerland Nanometer scale structures embedding molecular compounds represent a versatile test-bed to investigate non-equilibrium quantum transport phenomena. We follow two experimental routes to characterize and control electronic transport in molecular junctions. Using atomic contacts prepared with a mechanically-controllable break junction system, we investigate the electro-mechanical properties of individual molecular junctions. Operating these devices in a liquid environment, we have for instance observed the importance of intermolecular interactions and pi-pi stacking effects [1]. Molecular junctions are not static devices and undergo dynamical reconfigurations. By acquiring IV characteristics at a relatively high rate, we can follow the time evolution of the junctions and gain insight in the various geometries explored and their electronic properties. Conducting AFM further provides the possibility to simultaneously investigate the electrical and mechanical properties of Au-Au and Au-molecule-Au junctions [2]. Using Au nanoparticle arrays as a backbone structure, we investigate the transport properties of molecular junctions networks. We have demonstrated that this platform can be efficiently used to study transport modulation effects via chemical [3] and optical [4] stimuli as well as study photoconductance effects [5]. 1. S. Wu et al., Nature Nano., 3, 569-574 (2008) 2. C. Nef et al., Nanotechnology, 23, 365201 (2012) 3. J. Liao, et al., Nano Letters, 10 (3), 759–764 (2010) 4. S. van der Molen, et al., Nano Letters, 9 , 76-80 (2009) 5. M. A. Mangold et al., ACS Nano, 6 (5) , 4181–4189 (2012)
2012
- Characterizing the mechanisms governing electrical transport in molecular junctions
Seminar
Department of Physics, University of Konstanz, Germany, December 14, 2012. - Chemosensing with Si nanowire field-effect transistors
Invited talk
Workshop on Semiconductor Nanowires Based Sensors, GdR Nanofils Semiconducteurs, Rennes, France, November 13-14, 2012. - Insights into the electronic and mechanical structure of molecular junctions
Invited talk
Workshop on Electronic and Excitonic Transport in Soft Matter, Black Forest Focus on Soft Matter 8, Freiburg Institute for Advanced Studies, Germany, October 10-14, 2012. - Electrical transport in molecular junctions: spectroscopy and switching behavior
Talk
SYMONE kickoff meeting, Chalmers University, Göteborg, Sweden, October 30, 2012. - Insights into the electronic and mechanical structure of molecular junctions
Invited talk
Joint International Conference of the Israel Institute for Advanced Studies and the Israel Science Foundation on Molecular Electronics – Hebrew University, Jerusalem, Israel, July 16th-20th, 2012. - Discussion moderation on ‘Exploiting inherent quantum effects at room temperature in single molecule junctions’
Invited moderator
Workshop "Future directions of molecular electronics", Lorenz Center, Leiden, The Netherlands, June 25th-29th, 2012.
2011
- Molecular junctions and devices: from tunneling to function
Colloquium
Antrittsvorlesung (Inaugural Lecture as Privat Docent), University of Basel, Switzerland, Oct. 7th, 2011. - Dual-gated Si (nano)wire FETs for ion- and bio-sensing
Invited talk
SINANO-Nanofunction Workshop, ESSDERC-ESSCIRC, Helsinki, Finland, Sept. 16th, 2011. - Dual-gated Si nanowire FETs for ion- and bio-sensing
Invited talk
FSRM Workshop on Innovative sensors in the Nano-Tera program, La Rouvraie, Bevaix, Switzerland, June 21, 2011. - Well ordered Au nanoparticles arrays: a template structure for molecular-scale electronics
Invited talk
GdR Or-nano Plenary meeting, Université Paul Sabatier, Toulouse, France, March 16, 2011. - Nanoelektronik: Reise in der Nanowelt
Talk
Gymnasium Liestal, Liestal, Switzerland, February 01, 2011.
2010
- Switching functionality in molecular junctions networks
Talk
ElecMol’10, 5th international meeting on molecular electronics, Grenoble, France, December 09, 2010. - Few molecules junctions: formation mechanisms, transport and spectroscopy
Seminar
Chemistry Department, MIT, Boston, USA, November 22, 2010. - Few molecules junctions: formation mechanisms, transport and spectroscopy
Colloquium
Physics Department, Lancaster University, Lancaster, UK, November 30, 2010. - Formation mechanisms and functionality in molecular junctions
Invited talk
Workshop on Carbon-based nanostructures, St Englmar (Regensgurg), Germany, October 4-6, 2010. - Voyage au coeur de la matière: nanosciences et nanotechnologie
Talk
Conférence publique, Club de la Joie du Lundi, Neuchâtel, Suisse, October 11, 2010. - Unraveling the formation mechanisms and functionality in molecular junctions
Seminar
Tyndall National Institute, Cork, Ireland, September 16, 2010. - A glimpse into the world of nano- and molecular electronics
Colloquium
Introduction talk to the Phd defence of Tobias Blom, Uppsala University, Sweden, June 9-10, 2010. - Formation mechanisms and functionality in molecular junctions
Invited talk
Electron and Spin Transport in Nanostructures Workshop, Albanova center, Stockholm, Sweden, June 9-10, 2010. - Networks of molecular junctions
Invited talk
BIMORE Summer School on Molecular Electronics, Billund, Denmark, June 21-26, 2010. - Voyage au coeur des nanosciences
Talk
Public event for the 550th Anniversary of the University of Basel, Porrentruy, Switzerland, May 8, 2010. - Electrically and mechanically controlled nanogaps for molecular electronics
Invited talk
Workshop on electromigration, Competence network on Functional Nanostructures, Karlsruhe, Germany, January 28-29, 2010.
2009
- Formation mechanisms and functionality in molecular junctions
Seminar
IPCMS, Université Louis Pasteur, Strasbourg, France, December 12, 2009. - Hybrid organic-inorganic devices: electrical functionality and sensing at the molecular level
Seminar
LMN, Paul Scherrer Institute, Villigen, Switzerland, December 15, 2009. - Formation mechanisms and functionality in molecular junctions
Seminar
IMDEA, Universidad Autonoma, Madrid, Spain, November 17, 2009. - Individual molecular junctions
Talk
Marie Curie FUNMOLS ITN Workshop on Single-Molecule Electronics, Copenhagen, Denmark, September 8-9, 2009. - Formation mechanisms and functionality in molecular junctions
Invited talk
CECAM Workshop, Quantum transport on the molecular scale, September 14-18, 2009. - Molecular junctions: Formation mechanisms and functionality
Invited talk
Unimolecular Electronics Center, Uppsala University, Sweden, February 9-12, 2008. - Molecular electronic junctions
Talk
Kick-off Meeting, Marie Curie FUNMOLS Initial Training Network, January 26-28 2009.
2008
- Electronics with single molecules: vision or reality?
Seminar
University of Applied Sciences, Muttenz, Basel, Switzerland, November 11th 2008. - Molecular electronic junctions with function
Seminar
ABB Corporate Research, Baden-Daetwil, Switzerland, October 21, 2008. - Molecular electronics junctions with function
Talk
First Transalpine Conference Nanosciences and Nanotechnologies Transalp’Nano 2008, Lyon, France, 27-29 October 2008. - Soft electronic junctions: from single molecules to networks
Seminar
IMT, University of Neuchâtel, Switzerland, July 3, 2008. - Molecular electronics junctions with function
Invited talk
Swiss Nanoscience Workshop, Davos, Switzerland, June 4-6, 2008. - Soft electronic junctions: from single molecules to networks
Invited talk
From Solid State to Biophysics IV, Cavtat, Dubrovnik, Croatia, 7-12 June 2008. - Le monde de la nanoélectronique: des fils de Silicium aux molécules
Invited talk
Workshop on Nanoscience, CIFOM, Le Locle, Switzerland, February 6th, 2008. - IsNanoSens: Integrateable Si Nanowire Sensing platform
Invited talk
Nano-Argovia Industry-day, Basel, Switzerland, February 26th 2008.
2007
- Versatile molecular junction networks from colloid arrays
Invited talk
EUROMAT 2007, Nuernberg, Germany, September 10-13, 2007. - From individual molecular junctions to networks
Invited talk
IWEPNM 2007, 21st Winter School on Molecular Nanostructures, Kirchberg, Austria, March 10-17 2007.
2006
- From single molecule contacting to networks of molecular junctions
Invited talk
Summer School on Molecular Nanostructures, DFG-Center for Functional Nanostructures, Bad Herrenalb, Germany, August 31 – September 2, 2006. - Molecular electronics: From single junctions to networks
Invited talk
Nanomesh Workshop, Braunwald, Switzerland, September 17-20, 2006. - Twenty years of two-coils technique: Piero’s eyes into superconducting phenomena
Colloquium
Workshop in honor of Prof. Piero Martinoli at the occasion of his retirement, September 22, 2006. - From single molecule devices to networks of molecular junctions: Parts I & II
Invited talk
International Workshop on Molecular Electronics, Rez, Prague, June 29 – July 4, 2006. - Paving the road for single molecule electronics
Invited talk
Nanoconvention Scientific Workshop, Bern, Switzerland, June 2006. - From single molecules junctions to networks of molecular junctions
Talk
SONS Workshop, Kloster-Irsee, Germany, April 26-29, 2006.
2005
- Molecular junctions: from single molecules to networks
Seminar
Schottky seminar, Walter Schottky Institute, Münich, Germany, June 21, 2005. - Electronic properties of C60 molecular junctions in liquid
Talk
NCCR Nanoscale Science Workshop, Gwatt, Switzerland, October 6-7, 2005.
2004
- Break junctions and nanogaps for molecular electronics
Invited talk
From Solid State to Biophysics II, Dubrovnik, Croatia, June 26 – July 2 2004. - Carbon nanotubes: next generation biosensors ?
Invited talk
Micro- and Nano-Technologies in the Life Sciences, Technology Transfer and Investment days, Technopark Zürich, July 6-7 2004. - Electrical characterisation of DNA molecules
Invited talk
Workshop ‘Nano-Physics of DNA’, 320th WE-Heraeus Seminar, Bad-Honnef, March 22-24 2004. - Single molecule manipulation and characterisation using nanoscale devices
Invited talk
Workshop on Single Molecule Biophysics, NCBS Bagalore, India, January 4-15 2004.