The binding energy of each emitted electron can be calculated using the equation below since the energy of the x-rays being emitted is known.Į binding is the binding energy of the electron, E photon is the energy of the x-ray photons, E kinetic is the kinetic energy that is measured by the XPS, and F is the work function of the spectrometer.įigure 1.
There are tables with the kinetic energies as well as binding energies already in the system that will help identify the elements present in the surface of the material. Since each element will produce a characteristic peak at characteristic binding energies, the element at the surface can be identified and because the number of electrons in each peak is directly related to the amount of the element, the elemental composition within the area that is being analyzed can be calculated. the binding energy of the electrons detected (Figure 2). With this information you can obtain an XPS spectrum which plots the number of electrons detected vs. It will also count the number of photoelectrons that are being ejected from the surface with the cylindrical mirror detector analyzer. When the x-ray photons hit the sample, they transfer this energy to core electrons and are emitted from the initial state with a kinetic energy which is being measured (Figure 1). The XPS functions by irradiating a surface with a beam of x-rays which are usually monochromatic Al Ka (1486.6eV) or non-monochromatic Mg Ka (1253.6eV) in an ultra-high vacuum. Other examples include paints, inks, viscous oils, wood and papers. Some examples that can be analyzed using the XPS are elements, metal alloys, semiconductors polymers, ceramics, and inorganic compounds. Preparation of the samples is minimal if any you can analyze samples “as receive” or can clean the surface to eliminate any contaminates that might be present. Also, it can only analyze depths ranging from 1 to 10nm, for this reason it only gives analysis of the surface. This instrument will only detect elements with an atomic number higher of 3 and higher since hydrogen and helium atoms are very small and the probability of detecting them is almost zero. The XPS will measure the elemental composition, chemical state as well as the electronic state, thickness measurements of overlayers (up to 8nm), and will give you the empirical formula of the material that is being analyzed. X-Ray photoelectron spectroscopy (XPS), also known as electron spectroscopy for chemical analysis (ESCA) is a non-destructive technique used to analyze the surface of a material. Click here to see other posts about XPS Only 10 $ for interpretation of each element in your XPS spectrum
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