Application Notes

The Application Notes are written by both internal and external scientists based on remarkable and interesting results and measurements done by Scienta Omicron systems and instruments. These Notes offer product specifications, in-depth analysis and added information on measurements and instruments. Also, references to publications or Scienta Omicron users for further reading or information is found to promote papers and networking in the scientific community.

Valence Band Spectroscopy using VUV5000

The change in line shape and peak positions of valence band photoemission (PES) spectra due to change in excitation energy can be attributed to cross sections. This fact can be used in valence band studies to assign features to specific element and orbital configurations, as done by the group of Professor Maiti, using HeI (21.2 eV) and HeII (40.8 eV) light for determining the valence band composition of the EuFe2As2 compound.

Probing bulk band structure using ARPES

Traditionally, angular resolved photoemission (ARPES) is used to study the band structure of materials. The photon range used normally makes the technique surface sensitive. In order to increase the bulk sensitivity of the technique, ARPES spectra could be acquired using higher excitation energies. As the energies are increased the demands of the analyser, in terms of energy and angular resolution, is increasing. In this application note we present data from Chuck Fadley and co-workers, recorded using VG Scienta hemispherical analysers, showing band structure for > 1keV kinetic energies and true hard x-ray (HAX) angular resolved spectra at  6 KeV: data that have revolutionized the method of ARPES as it now allows probing the true bulk band character of a material.

Plasmaronic Particles in Graphene

Graphene has rendered a huge interest over the last years due to its promising future in a variety of fields, such as in electronic applications where it is a candidate for ‘post-silicon’ transistors. But it also offers new insights in physics.

nanoARPES or k-Microscope

In nanotechnology and nanoscience the objects are in the order of 10-9 m. The properties are known to be different for a material in the nano-meter size compared to bulk. An important factor to understand and control these property changes is to gain insight in the electronic properties of the material, not only with high resolution in energy, angle and reciprocal space, but also with high lateral resolution. Photoelectron spectroscopy is a perfect tool for electron property studies; with x-ray photoelectron spectroscopy (XPS) it is possible to study the core levels of a material and acquire element specific chemical information and with angular resolved photoelectron spectroscopy (ARPES) it is possible to map the band structure of a material. In order to make use of XPS and ARPES in nanoscience Maria Carmen Asensio et al. have developed a new technique where the light is focused down to nanometre size – defining the area studied with photoelectron spectroscopy (PES) to be in the nano meter size.