Surface analysis Essay Example | Topics and Well Written Essays - 2000 words

Surface analysis - Essay Example For example, corrosion in metal is prevented through the use of specific chemicals; various optical effects on lenses may be done through special coatings; and automobile emissions are significantly reduced through the unique chemical composition on the surface of an auto-exhaust catalyst. To achieve the desired function, the surface a material should be analyzed to determine its physical characteristics, chemical composition, chemical and atomic structure, electronic state, and molecular bonding (Vickerman, 2009). Methods Several probes may be applied on a solid surface to measure its response, namely: electrons, ions, neutrons, photons, and heat or field. Each probe has a specific response. The combination of probes and corresponding responses provides 36 basic classes of experimental techniques which may be utilized for surface analysis. Table 1 Most Commonly Used Surface Analysis Methods Incident Excitation Probe photon electron ion neutron electric/magnetic field Radiation Detec ted photon FTIR, Raman, XAFS, EXAFS, SFG, IR EDAX NRA GDOES electron XPS/ESCA, UPS, (AE) XAFS AES, SAM, SEM, TEM, LEED, RHEED, SPE, STM, EELS STM, AFM ion SIMS, LEIS, RBS, ISS neutron INS As shown in Table 1, the following shows the most commonly used surface analysis methods: FTIR – Fourier Transform Infrared Spectroscopy; Raman Vibrational Spectroscopy; XAFS – X-ray Absorption Fine Structure analysis; EXAFS – Extended X-ray Absorption Fine Structure analysis; SFG – Sum Frequency Generation; IR – Infrared Spectroscopy; EDAX – Energy Dispersive Analysis of X-rays; NRA – Nuclear Reaction Analysis; GDOES – Glow Discharge Optical Emission Spectroscopy; XPS/ESCA – X-ray Photoelectron Spectroscopy / Electron Spectroscopy for Chemical Analysis; UPS – Ultraviolet Photoelectron Spectroscopy; (AE) XAFS – Auger Emission X-ray Absorption Fine Structure analysis; AES – Auger Electron Spectroscopy; SAM –Sc anning Auger Spectroscopy; SEM – Scanning Electron Microscopy; TEM – Transmission Electron Microscopy; LEED – Low Energy Electron Diffraction; RHEED – Reflection High Energy Electron Diffraction; SPE – Spin Polarized Electron spectroscopy; STM – Scanning Tunnelling Microscopy; EELS – Electron Energy Loss Spectroscopy; AFM – Atomic Force Microscopy; SIMS – Secondary Ion Mass Spectrometry; LEIS – Low Energy Ion Scattering spectroscopy; RBS – Rutherford Backscattering Spectroscopy; ISS – Ion Scattering Spectroscopy; and INS – Inelastic Neutron Scattering; Analysis Auger electron spectroscopy or AES is considered as a key chemical surface analysis tool for conducting material samples. The AES technique is based on the excitation of auger electrons which allow not only the imaging of atoms but for chemical identification as well. Information available through AES ranges between the first 2 to 10 at omic layers of the sample surface (Matheiu, 2009). Meanwhile, low energy electron diffraction or LEED works by bombarding a surface with beam of low energy electrons which enable the identification of the surface structure by electron diffraction (Vickerman, 2009). A beam of low energy electrons between 10 to 200 eV is used to determine crystallographic structure. A device called a Retarding Field Analyzer is utilized to detect diffracted electrons. Diffracted electrons appear as spots on a phosphorescent screen which move according to energy variations of electrons. The intensity of the spots also provides information regarding surface reconstructions (Walker, 2011). An auger