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Jesper Wallentin

Position:    Assistant Professor

E-mail:    jesper.wallentin@sljus.lu.se
Phone:   
Cell phone:    +46 70 559 3949
Room:    K542
Address:    Professorsgatan 1
22100 Lund
      Sweden

University:    Lund University
Division:    Synchrotron Radiation Research
Research Area(s):    Materials Science
Nanoelectronics- & photonics
Interests:    X-ray analysis of nanostructures

 
jesper.wallentin

Teaching:

I teach physics at the Faculty of Science:
* FYSA01 General physics. Responsible for the Quantum physics part of the course.
* FYSN11 Physics experiments in Research and Society

If you are interested in a MSc project, don't hesitate to contact me.


Research:

My research studies single nanostructure devices using coherent X-ray imaging and X-ray diffraction. In particular, I'm developing techniques for investigations that combine hard X-ray imaging and X-ray diffraction with electrical measurements [3,5]. Hard X-rays can penetrate through thick samples, allowing measurements of devices in operando. The X-rays can both be used as a pump, to study for instance X-ray induced electrical conductance [5], or as a probe of the structure in nanodevices [3]. Nanowires have demonstrated much stronger response to hard X-rays than expected from bulk data [5]. We have shown that the shape of bent nanowires can be reconstructed in 3D with nanometre precision [2,3].

The image below shows a 3D reconstruction of a nanowire changing shape under the influence of a strong electric field [3].
NW_model_projections_xvid_gif_001.gif

The experiments require intense nanofocused X-ray beams that are only available at synchrotrons such as Petra-III and ESRF, and now also at MAX IV.

The image below shows a recent ptychographic reconstruction from the Nanomax beamline at the new MAX IV synchrotron, depicting a standing GaInP nanowire (courtesy Vilgaile Dagyte and Magnus Borgström).
particle_2_ptycho_object_cropped.jpg

We have simulated the heating from pulsed X-rays using the finite-element software Comsol [1]:
Repeated_pulses_angle_video_gif.gif


For an updated lists of publications, please see ResearcherID or Google Scholar. A selected list of recent work:
  1. H Wallander, J Wallentin: Simulated sample heating from a nanofocused X-ray beam J. Synchrotron Radiat. 24 (5) (2017) doi.org/10.1107/S1600577517008712
  2. J Wallentin, D Jacobsson, M Osterhoff, MT Borgström, T Salditt: Bending and twisted lattice tilt in strained core-shell nanowires revealed by nanofocused X-ray diffraction Nano Lett. 17 (7) (2017) (dx.doi.org/10.1021/acs.nanolett.7b00918)
  3. J. Wallentin, M. Osterhoff, and T. Salditt, "In operando X-ray diffraction reveals electrically induced strain and bending in single nanowire device" Adv. Mater. 28 (9), 1788 (2016) http://dx.doi.org/10.1002/adma.201504188
  4. M. Osterhoff, C. Eberl, F. Döring, R. N. Wilke, J. Wallentin, H.-U. Krebs, M. Sprung, and T. Salditt, "Towards multi-order hard x-ray imaging with multilayer zone plates" J. Appl. Crystallogr. 48, 116 (2015) http://dx.doi.org/10.1107/S1600576714026016
  5. J. Wallentin, M. Osterhoff, R. N. Wilke, K.-M. Persson, L.-E. Wernersson, M. Sprung, and T. Salditt, "Hard X-ray detection using a single 100 nm-diameter nanowire" Nano Lett. 14 (12), 7071 (2014) http://dx.doi.org/10.1021/nl5040545
  6. R. N. Wilke, J. Wallentin, M. Osterhoff, D. Pennicard, A. Zozulya, M. Sprung, and T. Salditt, "High-flux ptychographic imaging using the new 55 mm pixel detector Lambda based on the Medipix3 readout chip" Acta Crystallogr. Sect. A A70 (6), 552 (2014) http://dx.doi.org/10.1107/S2053273314014545

Jesper Wallentin's pages

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