OPTICONs "DEEM" Spectromicroscope qualified as a "BREAKING NEWS!" at the International Vacuum Congress IVC19, 9-13 September 2013 in Paris !



DualEEM: a novel surface science technique for simultaneous ultrafast electron spectromicroscopy, nanospectroscopy and diffraction

Krzysztof P. Grzelakowski

OPTICON Nanotechnology

Muchoborska 18, PL54-424 Wrocław, Poland

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We present experimental proof of the novel dual emission electron microscopy (DEEM) technique [1] based on photoemission (PEEM) [2] and low energy electron microscopy    (LEEM) [3]. DualEEM utilizes the idea of the aberration free spherical analyzer α-SDA [4], that assures not only the selection of characteristic energy for imaging, but also an electron optical separation into two imaging channels: energy-selective real image and reciprocal (diffraction) image. Their quasi- simultaneous acquisition in DualEEM offers an unique opportunity to investigate ultrafast dynamic processes on the surface under these two aspects on the sub-femtosecond scale [5]. The idea and its realization is illustrated in Fig.1. An electron gun located inside the immersion objective lens (b) allows a unique electron beam sample illumination and thus, opens a new application field for electron spectromicroscopy under laboratory conditions.

fig1 paris


Fig. 1. Modus operandi: α-rays (black), γ (blue), p1,p2: real and diffraction plane, respectively: a) E- selective k-projection, upper hemisphere switched off, b) E- selective real image mode, both hemispheres switched on, c) General appearance of the assembled flange-on DualEEM oriented as ‘a’ and ‘b’

The first test results (<45nm resolution in the spectroscopic modus) obtained from 2μm Pd/Si in ultrahigh vacuum are collected and described in Fig.2. (final res. <10nm, ΔE<100meV)


fig2 ivc paris3


Fig.2. Pd/Si, FoV of ‘a’ ~ 7,5μm, pass energy=700eV, top: UV(Hg) illumination, ΔE: 400meV,              disp.apt. :~80μm, a) E- selective real image, screen1; b) E-selective K-projection, screen2.                                                                                                                                                                                              bottom: selected area microspectroscopic analysis for two characteristic energy ranges that utlizes a unique method for sample electron beam illumination [1], Fig.1b.


  1. 1.K.P. Grzelakowski, Ultramicroscopy 130 (2013) 29
  2. 2.E. Brueche, Z.Phys. 86  (1933) 448
  3. 3.E. Bauer, Proc.of the 5thInt. Cong. for Electron Micr.(Academic, N.Y., 1962, p.D-11)
  4. 4.K.P. Grzelakowski, Ultramicroscopy 116 (2012) 95
  5. 5.K.P. Grzelakowski, R. M. Tromp, Ultramicroscopy 130 (2013) 36


Exhibition booth in Vienna                ...
new results   The DEEM resolution is continously improving towards 10nm!
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