XPS und UPS measurements with the ASTRAIOS analyzer

Angle-integrated UPS is commonly used to measure the occupied valence band density-of-states in order to determine the energetic position of electronic states near the Fermi level. These states govern the chemistry as well as the electrical properties of a material. The Ag sample was illuminated with UV photons with an energy of 21 eV, corresponding to the He I emission line from a SPECS UVS 300 UV source and focused onto the sample using µFOCAL VUV optics. The ASTRAIOS was operated in the wide-angle mode, with a conical acceptance angle of 40 degree. The size of the entrance slit within the lens optics, virtual entrance slit mechanism, is set to 50µm. At room temperature the measured width of the fermi level, 107 meV, is mainly determined by thermal broadening.

Furthermore, we performed XPS measurements on the same area of the Ag sample with a SPECS focused x-ray monochromator µFOCUS 500, using Al Kα with an energy of 1486.61 eV. In the main panel of the figure below, the Ag 3d3/2 and Ag 3d5/2 lines are plotted for different pass energies of the ASTRAIOS analyzer, ranging from 7.5 to 60 eV. The inset of the figure is from the survey spectrum of the Ag sample measured in medium area mode with a pass energy of 50 eV and shows a smooth transmission of the analyzer in the entire energy range. 

The ASTRAIOS 190 is a revolutionary ARPES analyzer for 2D momentum mapping. It is based on a direct k-mapping single spot shifting lens with a virtual entrance slit for ultimate k- and energy resolved measurements.