The ESCALAB 250Xi is a fully digital state-of-the-art X-ray photoelectron spectrometer (XPS) capable of performing a large suite of surface analysis experiments. The instrument is used routinely for elemental analysis (Li-U) and for chemical state analysis, differentiating between the different functional groups that a given element is bonding to (for instance, C-C verses C=C verses C=O). 

The instrument is capable of conducting a wide range of surface analysis experiments. Some of these include:

• XPS, X-ray photoelectron spectroscopy
  • Control of X-ray spot size from 900 to 200 um with monochromatic Al Ka X-rays and 0.5 m Rowland circle monochromator
  • In lens and external electron flood guns for analysis of insulators and non-conducting samples
  • Ultimate energy resolution <0.45 eV
• UPS, ultraviolet photoelectron spectroscopy
  • measurement of valence band structure (similar to the density of states, DOS) and the Fermi edge
  • HeI and HeII (21.22 eV and 40.81 eV) excitation source
  • 100 meV energy resolution
• ISS, low energy ion scattering spectroscopy
  • measurement of chemical composition of the upper atomic monolayer of the sample
  • 1 keV He⁺ ion source 
  • Energy resolution 12 eV FWHM at approximately 30,000 cps/nA ion current
• REELS, reflected electron energy loss spectroscopy
  • measurement of geometry, electronic and optical properties via the dielectric function, and structure of absorbed species on the sample surface
• TPD/TPRS, temperature programmed desorption/temperature programmed reaction spectroscopy
  • Allows analysis of gas-solid interactions by monitoring desorption of gas molecules as sample is heated
  • Gas dosing system for carrying out in situ reactions in both the analysis and load lock chamber
  • ​Single quadrupole mass analyzer for collection of mass spectra at pressure below 10^-7 mbar
  • Temperature control of samples from 77 to 1000 K in both the analysis and load lock chamber
  • Reactions may be carried out from ultra-high vacuum conditions to atmospheric pressure
• Small spot XPS
  • Use of magnetic immersion lens allows for selective analysis of areas smaller than the X-ray beam, down to 30 um or better
  • Allows for mapping of surface features on heterogeneous samples
• XPS imaging
  • 128 element multichannel plate (MCP) detector for collection of images
  • full hyperspectral data collection for each image pixel
  • Spatial resolution better than 3 um
• Angle resolved XPS (ARXPS)
  • for the depth profiling of thin films (< 10 nm)
  • full 5-axis motion control including 160^o stage tilt
• Depth profiling by Ar⁺ sputtering for thicker layered samples