What Is Surface Analysis?
Surface analysis is a technique that involves irradiating the surface of a target material with electron beams, X-rays, ions, or similar excitatory sources. This method detects the electrons, ions, or other particles emitted from the irradiated site to reveal the sample’s state at the molecular and atomic levels. It is particularly useful for analyzing chemical states and elemental compositions of substances that may be challenging to analyze by other methods.
Uses of Surface Analysis
Surface analysis applies to a wide range of materials, including organic substances, semiconductors, and inorganic materials. Specific methods like XPS (X-ray Photoelectron Spectroscopy), TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometry), and AES (Auger Electron Spectroscopy) are employed for various analytical purposes, such as analyzing contaminants, determining molecular weights, and conducting qualitative and semi-quantitative element analyses.
Principles of Surface Analysis
Surface analysis operates on the principle that when an excitatory source is applied to the sample surface, it alters the energy state of surface atoms, causing the emission of particles like electrons and ions. Analyzing these emitted particles can clarify the sample surface’s state and structure. The depth of analysis and the types of particles emitted depend on the excitatory source and the analysis method used.
Types of Surface Analysis
Various methods are available depending on the depth and nature of the sample surface analysis required:
- XPS (X-ray Photoelectron Spectroscopy): Also known as ESCA, this method uses X-rays to irradiate the sample surface, emitting photoelectrons whose energy spectrum reveals the elemental composition and bonding state of the surface.
- TOF-SIMS (Time of Flight Secondary Ion Mass Spectrometry): This method involves irradiating the sample surface with an ion beam, and analyzing the emitted ions (secondary ions) to obtain elemental composition information and chemical structure details with high accuracy.
- AES (Auger Electron Spectroscopy): This technique uses an electron beam to irradiate the sample surface, emitting “Auger electrons” whose unique energies allow for elemental analysis.