Surface analysis Assignment Example | Topics and Well Written Essays - 1750 words

Surface analysis - Assignment Example These ions on collision dislodge atoms from the surface creating secondary ions. Using a combination of electrostatic and magnetic fields which distinguishes the ions on the mass to charge ratio, these secondary ions are drawn into a mass spectrometer. By varying the strength of the magnetic field one can assess ions of different mass to charge ratios. (Surface Analysis, 2000) Some of the applications of SIMS include (i) Identifying the isotopes in a material that might have same atomic masses as it is capable of producing mass resolutions to tune of 7000. (ii) It is capable of finding out the extent of impurity concentration present in a specimen and represents the same as a function of depth. The sensitivity of this instrument is in the range of 1 ppb (-10^13 at/cm^3) (iii) It can accurately map the interface layers and the impurities that may be located at these grain boundaries. (iv) It uses the raster scanning technique to produce three dimensional images of the grain distributi on. (v) Using the secondary ions it can directly produce an image showing the arrangement of trace elements. Source: Surface Analysis, 2000 2. ... Some of the applications of AES include (i) This is used to identify compositions of elements in solid materials with high output sensitivities in the range of 0.5 atomic percent for lithium to uranium. (ii) This is useful in carrying out the volumetric analysis of a specimen. (iii) This is capable of producing magnified images to the tune of 20000x and is used extensively in microelectronics. 3. X-Ray Photoelectron Spectroscopy (XPS) (Surface Analysis, 2000) This advanced technique uses x rays in dislodging electrons from specimens and these have distinct kinetic energies depending on the nature of emitted electrons. It is particularly useful in providing information regarding the type of bonds that exist between electrons. This is because any change in binding energy is reflected in the XPS spectrum chart which shows crests and troughs. The crests obviously reflect the high chemical boding energy that existed and the troughs vice versa. Its applications include (i) Determining mole cular composition of surfaces along with information regarding the atomic bonding. (ii) It can identify very accurately to the tune of 0.5 atomic % the presence of lithium and uranium. (iii) This can create depth profiles for materials in the range of 1Â µm thickness. (iv) This method of analysis is particularly useful to study functional groups in polymers. 4. Scanning Probe Microscopy (SPM) This is also referred to as Atomic Force Microscopy (AFM). This is capable of generating a profile that shows the topographical nature of the specimen surface. Schematic of atomic force microscope operation Source: Surface Analysis, 2000 This essentially consists of a tip mounted on a cantilever. The specimen is placed below this cantilever and