Vacuum Nanoelectronics

We have been studying all-metal field emitter array (FEA) cathode [1-14] as a potential high current and high brilliance electron source for advanced accelerator applications e.g. X-ray free electron lasers such as SwissFEL [15], requiring stringent cathode specs: high current (200 pC in 10 ps), low normalized transverse emittance (0.4 mm-mrad), and compatibility with the high acceleration electric field in the order of 100 MV/m.

For that, we have proposed the double-gate nanotip FEAs with surface-plasmon-enhanced laser-induced field emission: electrons from 1 million nanotips are produced by near infrared laser pulses, of which optical electric field is enhanced via the surface-plasmon-polariton resonance of the cupper-double-gate structure and the lightening rod effect at the molybdenum nanotip apexes.

The double-gate FEAs with the demonstrated collimation capability are expected to open up new electron beam applications including micro electron microscope, sub-THz and THz vacuum electronic power amplifiers, ultra-compact mass spectrometers, compact X-ray sources, parallel e-beam lithography tools, etc.

In collaboration with the University of Hamburg, we also conduct research directing to developing the brightest, next generation electron sources, for atomically resolving the structure-function correlation in biological systems to directly observe biology in action at atomic level.

References

[1] S. Tsujino, P. Beaud, E. Kirk, T. Vogel, H. Sehr, J. Gobrecht, and A. Wrulich, Ultrafast electron emission from metallic nanotip arrays induced by near infrared femtosecond laser pulses, Appl. Phys. Lett. 92, 193501 (2008).
[2] S. Tsujino, F. le Pimpec, J. Raabe, M. Buess, M. Dehler, E. Kirk, J. Gobrecht, and A. Wrulich, Static and optical field enhancement in metallic nanotips studied by two-photon photoemission microscopy and spectroscopy excited by picosecond laser pulses, Appl. Phys. Lett. 94, 093508 (2009).
[3] A. Mustonen, P. Beaud, E. Kirk, T. Feurer, and S. Tsujino, Five picocoulomb electron bunch generation by ultrafast laser-induced field emission from metallic nano-tip arrays, Appl. Phys. Lett. 99, 103504 (2011).
[4] A. Mustonen, P. Beaud, E. Kirk, T. Feurer, and S. Tsujino, Efficient light coupling for optically excited high-density metallic nanotip arrays, Scientific Reports, 2, 915 (2012).
[5] S. Tsujino, P. Helfenstein, E. Kirk, T. Vogel, C. Escher, and H.-W. Fink, Field-Emission Characteristics of Molded Molybdenum Nanotip Arrays With Stacked Collimation Gate Electrodes, IEEE Electron Device Letters, vol. 31, 1059 (2010).
[6] P. Helfenstein, E. Kirk, K. Jefimovs, T. Vogel, C. Escher, H.-W. Fink, and S. Tsujino, Highly collimated electron beams from double-gate field emitter arrays with large collimation gate apertures, Appl. Phys. Lett. 98, 061502 (2011).
[7] P. Helfenstein, K. Jefimovs, E. Kirk, C. Escher, H.-W. Fink, and S. Tsujino, Fabrication of metallic double-gate field emitter arrays and their electron beam collimation characteristics, J. Appl. Phys. 112, 093307 (2012).
[8] P. Helfenstein, V. A. Guzenko, H.-W. Fink, and S. Tsujino, _Electron beam collimation with a 40 000 tip metallic double-gate field emitter array and in-situ control of nanotip sharpness distribution, J. Appl. Phys. 113, 043306 (2013).
[9] S. Tsujino, M. Paraliev, E. Kirk, T. Vogel, F. Le Pimpec, C. Gough, S. Ivkovic, and H.-H. Braun, _Nanosecond pulsed field emission from single-gate metallic field emitter arrays fabricated by molding, J. Vac. Sci. Technol. B29, 02B117 (2011).
[10] S. Tsujino, M. Paraliev, E. Kirk, C. Gough, S. Ivkovic, and H.-H. Braun, Sub-nanosecond switching and acceleration to relativistic energies of field emission electron bunches from metallic nano-tips, Phys. Plasmas 18, 064502 (2011).
[11] S. Tsujino, M. Paraliev, E. Kirk, and H.-H. Braun, _Homogeneity improvement of field emission beam from metallic nano-tip arrays by noble-gas conditioning, Appl. Phys. Lett. 99, 073101 (2011).
[12] P. Helfenstein, A. Mustonen, T. Feurer, and S. Tsujino, _Collimated Field Emission Beams from Metal Double-Gate Nanotip Arrays Optically Excited via Surface Plasmon Resonance, Applied Physics Express, 6, 114301 (2013).
[13] S. Tsujino and M. Paraliev, _Picosecond electrical switching of single-gate metal nanotip parrays, J. Vac. Sci. Technol. B 32, 02B103 (2014).
[14] A. Mustonen, V. Guzenko, C. Spreu, T. Feurer, and S. Tsujino, High-density metallic nano-emitter arrays and their field emission characteristics, Nanotechnology 25, 085203 (2014).
[15] B. Patterson, R. Abela, H.-H. Braun, U. Flechsig, R. Ganter, Y. Kim, E. Kirk, A. Oppelt, M. Pedrozzi, S. Reiche, L. Rivkin, Th. Schmidt, B. Schmidt, V. N. Strocov, S. Tsujino, and A. F. Wrulich, Coherent science at the SwissFEL x-ray laser, New J. Physics, 12, 035012 (2010).

Sub-projects