High Kinetic Energy Photoelectron Spectroscopy
|Energy range||Si(111):2 - 12 keV; Si(311): 4 - 12 keV; Si(422): 6 - 12 keV|
|Energy resolution||1000 at 4 keV|
|Flux||1e11 at 4 keV|
|Focus size (hor. x vert.)||0.4 x 0.6 mm|
|Phone||+49 30 8062 14838|
|Temperature range||tested: 71 K to 1023 K|
|Pressure Range||5 x 10-9 mbar to 5 x 10-7 mbar|
|Detector||VG Scienta R4000 electron analyzer up to 10 keV, Bruker XFlash ® 4010 fluorescence detector|
|Manipulators||VG Scienta He cryostat with 5 degrees of freedom - 4 motorized|
|Sample holder compatibility||Omicron type|
|Manipulator motorization||Axis X, Y, Z, Polar - Labview controlled|
|Sample transfer||Omicron type|
|Sputter gun||yes; Available gas: Argon|
|Charge compensation flood gun||yes - with electron energies up to 300 eV|
|X-ray Focusing||Glass Capillary X-ray Optics: parabolic x-ray mono-capillary (IfG GmbH) Beam properties @ experiment: Focus: 100 microns x 50 microns; Flux density gain: x15; HIKE overall signal gain: x5.|
The HAXPES Spectrometer
The HIKE end-station has been set-up in late 2005 and begun user operation in 2006. The system is designed for hard X-ray high kinetic energy photoelectron spectroscopy (HAXPES or HIKE) experiments using a photon excitation energy range from 2 keV to 12 keV with an optimized available photoelectron kinetic energy range from 150 eV to 10000 eV.
While soft x-ray photoelectron spectroscopy, e.g. ESCA, is one of the most important spectroscopic tools of today due to its surface sensitivity, HAXPES goes beyond the surface and probes the true bulk electronic properties of materials. The technique insensitivity to surface effects and contaminants allows the study of samples without particular surface treatments such as prototype systems for applications such as magnetic memories, solar cells, batteries, etc.
The HIKE end-station is installed at the KMC-1 beamline. Typical experiments running on the HIKE end station are investigations of bulk samples, multilayers and heterostructures where core levels and valence band are recorded, buried interfaces are accessed and spatially resolved chemical information by x-ray standing waves is recorded. In addition to HAXPES experiments the station also provides parallel access to the sample drain current (TEY) and the signal from a fluorescence detector (FY) thus enabling absorption experiments: XANES and EXAFS.
- extended depth profiling yielding stoichiometry and chemistry information
- buried interface chemistry investigations e.g. diffusion, order disorder transitions
- standing waves enhanced HAXPES
E. Holmström, W. Olovsson, I. A. Abrikosov, A.M.N. Niklasson, B. Johansson, M. Gorgoi, O. Karis, S. Svensson, F. Schäfers, W. Braun, G. Öhrwall, G. Andersson, M. Marcellini, W. Eberhardt, "A Sample Preserving Deep Interface Characterisation Technique", Physical Review Letters 97 (2006) 266106.
O. Karis, S. Svensson, J. Rusz, P. M. Oppeneer, M. Gorgoi, F. Schäfers, W. Braun, W. Eberhardt, N. Mårtensson, "High-kinetic-energy photoemission spectroscopy of Ni at 1s: 6-eV satellite at 4 eV", Physical Review B 78 (2008) 233105.
M. Sing, G. Berner, K. Goß, A. Müller, A. Ruff, A. Wetscherek, S. Thiel, J. Mannhart, S. A. Pauli, C. W. Schneider, P. R. Willmott, M. Gorgoi, F. Schäfers, R. Claessen, "Profiling the Interface Electron Gas of LaAlO3/SrTiO3 Heterostructures with Hard X-Ray Photoelectron Spectroscopy", Physical Review Letters 102 (2009) 176805.
H. Mönig, Ch.-H. Fischer, R. Caballero, C. A. Kaufmann, N. Allsop, M. Gorgoi, R. Klenk, H.-W. Schock, S. Lehmann, M.C. Lux-Steiner, I. Lauermann, "Surface Cu depletion of Cu(In,Ga)Se2 films: an investigation by hard X-ray photoelectron spectroscopy", Acta Materialia 57 (2009) 3645
S. Döring, F. Schönbohm, U. Berges, R. Schreiber, D.E. Bürgler, C.M. Schneider, M. Gorgoi, F. Schäfers, C. Papp, B. Balke, C.S. Fadley, C. Westphal, "Hard x-ray photoemission using standing-wave excitation applied to the MgO/Fe interface," Physical Review B 83 (2011) 165444.
R. Schölin, M.H. Karlsson, S.K. Eriksson, H. Siegbahn, E.M. J. Johansson, H. Rensmo, "Energy Level Shifts in Spiro-OMeTAD Molecular Thin Films When Adding Li-TFSI," The Journal of Physical Chemistry C 116 (2012) 26300.
B. Philippe, R. Dedryvere, M. Gorgoi, H. Rensmo, D. Gonbeau, and K. Edstrom, "Improved performances of nanosilicon electrodes using the salt LiFSI: a photoelectron spectroscopy study," J. Am. Chem. Soc. 135 (2013) 9829.