UGC-DAE Consortium for Scientific Research
( An Autonomous Institution of University Grants Commission, New Delhi )
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Electron Spectroscopy for Chemical Analysis (ESCA)
Dr. V. Ganesan/Dr. U.P. Deshpande
  • Mg and Al twin anode X-ray gun for X-ray Photo electron spectroscopy
  • Electron gun for Auger spectroscopy
  • He UV lamp for Ultra Violet Photo electron spectroscopy
  • Ar sputtering gun for surface etching / depth profiling
  • Sample scrapper assembly
  • Hemispherical analyser with multichannel detector

Angle dependent XPS measurements
Surface sensitivity can be varied by varying sample tilt angle as shown below
Related publications:

  • Non-toxic, earth-abundant 2% efficient Cu2SnS3 solar cell based on tetragonal films direct-coated from single metal-organic precursor solution

      D. Tiwari, T.K. Chhaudhuri, T. Shripathi, U. P. Deshpande, R. Rawat, Solar Energy Materials and Solar Cells, 113 (2013) 165.

  • Structural Studies and Valence Band Splitting Parameters in Ordered Vacancy Compound AgGa7Se12

      R. Jacob, R. Geethu, T. Shripathi, V. Ganesan, U. P. Deshpande, S. Tripathi, B. Pradeep, R. R. Philip, J. Inorg. Organomet. Polym. 23 (2013) 424.

Chemical state information

The binding energy of Cu 2p1/2 and Cu 2p3/2 peaks are 953.2 and 933.4 eV, respectively. The absence of shake-up or satellite peaks around 942 eV implies the nonexistence of Cu2+ ion. The binding energies for Sn 3d5/2 and Sn 3d3/2 are 486.6 and 495.03 eV, respectively and that for S2p3/2 and S2p1/2 are 160.89 and 162.04 eV, respectively. The experimental data indicates that Cu and Sn are present in +1 and +4 oxidation states. According to the quantitative analysis, the relative concentration of Cu, Sn and S is found to be 30%, 15% and 49%, respectively. Whereas, concentration of C and O is 1% and 3%, respectively. The [Cu]/[Sn] ratio suggests slightly Cu deficient and Sn excess stoichiometry.

ESCA (electron Spectroscopy for Chemical Analysis) is a surface sensitive technique that  provides information about

  1. Chemical composition (atomic percent of elements present in the sample)
  2. Oxidation state (chemical state) of the constituent elements
  3. Valance band structure (density of occupied electronic states)