Equipment

Our main experimental facilities are integrated systems for the preparation of thin films and the analysis of surfaces by photoemission (XPS/UPS),  low energy ion scattering (LEIS) and electron diffraction (LEED)…..

FACILITIES

(1)  The central multi-technique facility of the Surface Science Laboratory consists of a horizontally mounted, turbo- and ion-pumped and μ-metal shielded ultra-high-vacuum stainless steel chamber with three working sections.The first section is interfaced with a sample fast-entry system.Communication between these sections is achieved via a long (60 cm) z-drive sample manipulator, which, in addition , allows: micrometer-controlled motion in the x , y directions, 360° axial rotation, 100° azimuthal rotation perpendicular to its axis, heating and cooling of the specimen stage (-120 to 850° C) and electrical isolation of the specimen stage from ground.The following sample treatment and surface characterization pieces of equipment are mounted on the chamber :

• – A Ribere/Cameca argon ion gun with capability for scanning the ion beam over the surface of the specimen.
• – Home-built evaporation sources, for in situ deposition of thin films on various surfaces, as well as an organic liquid vapor introduction  system.
• – A Leybold EA-11 hemispherical Electron / ion Energy Analyzer with 150 mm hemispheres , a non-magnifying electron lens assembly and a rectangular entrance slit controllable in size between 1×1 and 5×1 mm.
• – A Specs/XR-30 dual anode, non-monochromatic X-ray source (MgK_α and AlK_α ), which is used, in combination with the analyzer, for the implementation of the X-ray Photoelectron and Auger Electron Spectroscopy (XPS/XAES).
• – A Specs Ultra Violet light source ( He I and He II) , which is used , in combination with the analyzer for the implementation of the UV Photoelectron Spectroscopy (UPS).
• – A Specs electron source ( PU-EQ 22) , which is used , in combination with the analyzer for the implementation of the Auger Electron and Electron Energy Loss Spectroscopy (AES, EELS).
• – A Specs ion source ( PU-IQE 12/38) , which is used , in combination with the analyzer for the implementation of the Ion Scattering Spectroscopy (ISS).
• – A Δφ–Εlektronik , S-type Kelvin Probe for measurements of sample surface Work Function (WF) changes in conductive specimens.
• – A WA Technology reverse view LEED facility with three-grid optics and Z-retraction. The VSI Aida-PC video-LEED system is used, in combination with the LEED facility in order to perform real time monitoring and intensity measurements on the LEED patterns of single-crystalline samples .
• – A Balzers Quadrupole Mass Analyzer (200 AMU, Channeltron, axial filaments).

The QMA is mounted in a differentially-pumped, internally fitted cell, which ends up in a 1.5mm diameter nozzle facing the sample. The whole QMA assembly can be positioned by Z-retraction as close to the specimen surface as desired.The Analyzer, the QMA and the video-LEED system are interfaced with PC for data acquisition and preliminary treatment. More advanced treatment and graphic presentation of the data are possible using a number of special software packages available at the SSL.

 (2) Since 2008, SSL has upgraded and enhanced its surface analytical facilities, through the acquisition of an additional, fully automated Surface Analysis System (MAX200 from LEYBOLD / SPECS). The main use of this system is currently in offering surface analytical services ( XPS/XAES/ISS ) to interested users both within and outside the University of Patras.

 (3) Since 2005, a complete DC sputtering system has been installed and operates at the SSL (in collaboration with other faculty members). Using this system, one can prepare high purity and uniformity films of controlled thickness on heated substrates.