CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 3
Fig. 3.7: Schematic of X-ray photoelectron spectroscopy showing (1) X-ray source, (2) sample,
(3) electronic focusing system, (4) spectrometer (5) electron detector or channeltron and (6) data
acquisition system [92].
The selection of X-ray source depends on many factors such as (a) energy resolution of X-
ray, (b) energy of the photons that are produced, and (c) the ease of application plication as an anode
material. Based upon these criteria, Al K (1486.6 eV) and Mg K (1253.6 eV) are universally
used in laboratory XPS studies. The monochromatization of the X-ray source is carried out
according to the Bragg’s relation by diffraction of a crystal for reduced back ground, narrow peak
width, and filtering of satellite peaks. The monochromatized X-ray source is then refocused to a
point where the specimen is located. The irradiation of the specimen with X-ray source causes
emission of electrons (photoelectrons) of discrete energy by means of photoelectric effect. The
analysis of energies of these photoelectrons escaped from the surface of the specimen is the most
important part of XPS measurement. Thus, an electron energy analyzer (spectrometer) is often
used to measure the kinetic energy of the ejected electrons. The basic function of the spectrometer