Description: XPS is a surface sensitive method for chemical analysis widely used for e. g. thin films, molecular layers or chemical surface modification. The sample is irradiated with monochromatic x-rays and photoelectrons from core level shells are released from the sample. The binding energies can be calculated from the measured kinetic energies and are characteristically for a specific chemical element. Additionally, chemical bond states can be determined by chemical shifts in binding energies.
- Multiprobe UHV-surface-analysis system (Omicron Nanotechnology);
- X-ray source: DAR400 aluminium-anode;
- Quartz-crystal monochromator XM 500;
- X-ray excitation energy: 1486,70eV (Al Kα1-line);
- Monochromated x-ray line width (FWHM): 0.2 eV;
- Energy analyzer: hemispherical analyzer, type EA 125;
- Signal-detection with pulse-counting channeltron (5 channels for count-rate enhancement);
- Total energy resolution (x-ray source + hemispherical analyzer): 0.4eV for detailed scans at 10eV pass-energy (+ lifetime broadening of the electronic state);
- Analyzed surface-aerea: around 1 mm in diameter;
- Maximum sample size: (10 x 10) mm2;
- Information depth: between 2 and 5 nm inelastic photoelectron mean free path (depending on material and kinetic energy);
- Charge-neutralization for non-conducting samples: electron-emissions-gun for low-energy electrons (0,1 – 500 eV): FG 15/40 (SPECS).