dr. J.J. (Jaco) Geuchies
J.J.Geuchies@uu.nl
Gegenereerd op 2017-10-18 05:56:38


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Many applications have been envisioned for supercrystals of quantum dots (QDs), ranging from solar cells to LEDs. The properties of such systems not only depend on the properties of the constituent particles, but crucially also on the structure of the supercrystal. Surprisingly, despite its potentially large impact, the effect of nanoscale geometry on the electronic properties of these 2-D semiconductors has been overlooked.

 

One particular example where the electronic properties are governed by the nanoscale geometry, is the honeycomb lattice. A supercrystal of QDs with this geometry will have a linear dispersion close to the Fermi level - like graphene - but dressed with unique features such as strong spin-orbit coupling. A recent discovery in the Condensed Matter and Interfaces group [1] will be further developed to a mature technology for the preparation of atomically coherent 2-D honeycomb semiconductors of metal-chalcogenides with strong (intrinsic) spin-orbit coupling.

 

In this project we will synthesize the constituent nanoparticles and assemble them into various nanocrystal superlattices. The nanogeometry will be studied using Transmission Electron Microscopy and its complementary techniques. The electronic properties will be characterized by scanning probe microspectroscopy (SPM) and by angle resolved photoelectron spectroscopy (ARPES). Furthermore the mechanism of formation of these superlattices will be studied using in-situ grazing-incidence small angle x-ray scattering (GISAXS). Hence, by means of imposing a well-defined nanogeometry, we will study non-trivial electronic phases in well-known and easily accessible semiconductors.

 

Motivated students who would like to perform their thesis in this very versatile subject are more than welcome to contact me!

[1] W.H. Evers et al., Nano Lett. 13 , 2317–2323 (2013).

 

Strategic themes / Focus areas
Involved in the following study programme(s)

(A) Model of a PbSe nanocube, with high resolution TEM images below. (B) TEM image of a large area of PbSe honeycomb superlattice, inset shows the corresponding electron diffractogram which shows the single-crystal nature of the system. (C) Honeycomb superlattice after ion exchange to CdSe, inset shows electron diffractogram after exchange.
Gegenereerd op 2017-10-18 05:56:38
All publications
  2016
Van Der Stam, Ward, Rabouw, Freddy T., Geuchies, Jaco J., Berends, Anne C., Hinterding, Stijn O M, Geitenbeek, Robin G., Van Der Lit, Joost, Prévost, Sylvain, Petukhov, Andrei V. & De Mello Donega, Celso (13.09.2016). In Situ Probing of Stack-Templated Growth of Ultrathin Cu2-xS Nanosheets. Chemistry of Materials, 28 (17), (pp. 6381-6389) (9 p.).
Geuchies, J.J., van Overbeek, C., Evers, W.H., Goris, Bart, de Backer, Annick, Gantapara, A.P., Rabouw, F.T., Hilhorst, J., Peters, J.L., Konovalov, Oleg, Petukhov, Andrei V., Dijkstra, M., Siebbeles, Laurens D A, Van Aert, S., Bals, Sara & Vanmaekelbergh, D.A.M. (2016). In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals. Nature Materials, 15 (12), (pp. 1248-1254) (7 p.).
Van Der Stam, Ward, Rabouw, Freddy T., Vonk, Sander J W, Geuchies, Jaco J., Ligthart, Hans, Petukhov, Andrei V. & De Mello Donega, Celso (13.04.2016). Oleic Acid-Induced Atomic Alignment of ZnS Polyhedral Nanocrystals. Nano Letters, 16 (4), (pp. 2608-2614) (7 p.).
  2014
Boneschanscher, M. P., Evers, W. H., Geuchies, J. J., Altantzis, T., Goris, B., Rabouw, F. T., van Rossum, S. A. P., van der Zant, H. S. J., Siebbeles, L. D. A., Van Tendeloo, G., Swart, I., Hilhorst, J., Petukhov, Andrei V., Bals, S. & Vanmaekelbergh, D. (20.06.2014). Long-range orientation and atomic attachment of nanocrystals in 2D honeycomb superlattices. Science, 344 (6190), (pp. 1377-1380) (4 p.).
Kalesaki, E., Boneschanscher, Mark, Geuchies, J. J., Delerue, C., de Morais Smith, Cristiane, Evers, W. H., Allan, G., Altantzis, T., Bals, S. & Vanmaekelbergh, D. (01.01.2014). Preparation and study of 2-D semiconductors with dirac type bands due to the honeycomb nanogeometry. In Alexandre Freundlich & Jean-François Guillemoles (Eds.), Physics, Simulation, and Photonic Engineering of Photovoltaic Devices III - 3–6 February 2014 San Francisco, California, United States SPIE.
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Gegenereerd op 2017-10-18 05:56:38
Full name
dr. J.J. Geuchies Contact details
Leonard S. Ornsteinlaboratorium

Princetonplein 1
Room -
3584 CC  UTRECHT
The Netherlands


Phone number (direct) +31 30 253 2220
Leonard S. Ornsteinlaboratorium

Princetonplein 1
Room ORNST. 110
3584 CC  UTRECHT
The Netherlands


Buys Ballotgebouw

Princetonplein 5
Room ORNST. 110
3584 CC  UTRECHT
The Netherlands


Phone number (direct) +31 30 253 2321
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Gegenereerd op 2017-10-18 05:56:38
Last updated 14.07.2014