The following is a list of the different surface science terms found on this
Web site. For each term the acronym and a brief description are listed. In
addition, links are provided (where availible) to tutorial sites that give more
complete information on the specific techniques.
|AES||Auger Electron Spectroscopy||A technique for measuring the chemical composition of the near surface region. An electron beam is used to ionize core holes in near surface atoms. One possible decay mechanism for this excited state involves an electron falling to fill the core hole, with a second electron being ejected to remove the excess energy. The kinetic energy of this ejected electron is then measured, and is characteristic of the emitting atom.||Yes|
|AFM||Atomic Force Microscopy||A sharp probe is scanned along the surface and the force exerted on the tip is measuremd. This gives information of the surface structure.||Yes|
|LEED||Low Energy Electron Diffraction||Low energy electrons have a wavelength comparable to crystal lattice dimensions, and thus are observed to diffract off of a crystalline surface. Analysis of the diffraction pattern produced can give information about the structure of the surface.||Yes|
|MOKE||Magneto-Optic Kerr Effect||In a MOKE (or SMOKE for surface MOKE) experiment a polarized laser is reflected off of the sample. This reflection rotates the polarization of the light by an amount that is proportional to the sample magnetization. By measuring this polarization rotation as a function of the applied magnetic field, the hystersis loop of the sample can be measured.||No|
|SEM||Scanning Electron Microscopy||The surface is scanned with a focused electron beam while the intensity of secondary electrons emitted by the sample is monitored. This produces an image of the surface morphology with resolution down to a few nanometers being possible.||Yes|
|SIMS||Seconday Ion Mass Spectrometry||The sample is bombarded with an energetic ion beam, resulting in the ejection of material in the form of positive and negative ions and neutral species. The ejected ions are then analyzed with a mass spectrometer to yield information about the chemical composition of the sample surface.||Yes|
|STM||Scanning Tunneling Microscopy||A sharp tip is scanned just above the surface of the sample and the tunneling current between the two is measured. This technique can give atomic resolution of surface structure.||Yes|
|TPD||Temperature Programmed Desorption||A sample containing an adsorbed species is heated while any material released from the surface is monitored by a mass spectrometer. Analysis of desorption temperatures can yield information about surface sites, binding strength and kinetics.||No|
|UHV||Ultra-High Vacuum||UHV is typically defined as oressures less that 1x10-9 torr of gas. Obtaining such vacuum condiutions is vital for surface science experiments, as only at this level will the sample stay clean for long enough to run experiments.||No|
|XPS||X-ray Photoelectron Spectroscopy||The sample is exposed to monoenergetic X-rays, resulting in the emission of electrons by the sample. The kinetic energy of these emitted electrons is characteristic of the X-ray energy and the emittor, and is used to identify the surface composition.||No|
|Sputtering||The removal of surface material by bombarding a surface with high energy ions. This is a commonly used procedure for cleaning metal samples.||No|
© Shirley Chiang - 1998.