Charging effects in X-ray photoelectron spectroscopy

When X-ray photons strike a surface, they cause the emission of electrons. This, of course, is the basis of the XPS technique. If the surface is electrically insulating, then the emission of electrons causes a positive charge to accumulate at the surface. When a non-monochromated source is used for XPS analysis there are usually a sufficient number of electrons in the region of the sample to limit the effect of the charging. However, when using a monochromated X-ray source for XPS measurements, there are too few stray electrons to control the charging and the resulting positive charge severely affects the XPS spectrum. It causes the peaks in the spectrum to shift to high binding energies and become distorted. For this reason, it is necessary to neutralize the charge on the surface by replenishing electrons from an external source. This stabilizes and controls the charging to within a few electron volts of the neutral state. Any remaining small shift can be removed after data collection is complete, by using the spectrum processing tools contained within the Thermo Scientific Avantage data system.

Combination electron beam and ion beam gun

The use of a single gun to produce both the focused low energy electron beam and the large area ion flux has a number of distinct advantages over the use of independent sources. A new, combined ion/electron gun has been designed which incorporates all the above advantages. This novel design uses a LaB6 emitter to produce a bright source of low energy electrons, with an energy spread of only about 0.3 eV. These are focused to a small spot on the sample. Precise alignment to the X-ray beam is provided using integral X-Y deflectors. Focusing and alignment of this low energy beam is enhanced by the extremely low residual magnetic fields present in the mu-metal analysis chambers.

Features of Charge Compensation for the ESCALAB Xi+ spectrometer

  • Patented ‘in the lens’ multi-mode electrostatic flood source
  • 0 - 5 eV (mode 1) charge compensation
  • 0 - 1000 eV (mode 2) REELS / imaging / alignment
  • Up to 500 µA electron emission
  • Additional dual beam (ion / electron) flood source

Features of Charge Compensation for Nexsa and K-Alpha spectrometers

  • Patented dual beam source
  • Single mode flood gun for all sample types
  • Single mode for all X-ray spot sizes
  • Ultra-low energy beam results in minimal shift from reference positions
  • Flood source assembly incorporating electrostatic deflection for precise alignment
  • REELS capability available for Nexsa
Charging Effects in XPS


用于将 H2 样式更改为具有 em-h2-header 类 p 的样式表

Nexsa G2 XPS

  • 微焦点 X 射线源
  • 独特的多技术选项
  • 用于单原子和簇离子深度剖析的双模式离子源

K-Alpha XPS

  • 高分辨率 XPS
  • 快速、高效、自动化的工作流程
  • 用于深度剖析的离子源


  • 高光谱分辨率
  • 多技术表面分析
  • 丰富的样品制备和扩展选项

Contact us