Quantitative AES and XPS: Determination of the electron spectrometer transmission function and the detector sensitivity energy dependencies for the production of true electron emission spectra in AES and XPS

Abstract For the use of published general or theoretical sensitivity factors in quantitative AES and XPS, the energy dependence of both the spectrometer transmission function and the detector sensitivity must be known. Here, we develop simple procedures that allow these dependencies to be determined experimentally. Detailed measurements for a modified VG Scientific ESCALAB II, the metrology spectrometer , operated in both the constant Δ E / E and constant Δ E modes, are presented and compared with theoretical estimates. It is shown that an exceptionally detailed electron‐optical calculation, involving proprietary information, would be required to match the accuracy of the experimental procedures developed. Removal of the spectrometer transmission function and the detector sensitivity terms allow the measured spectrum to be converted to the true electron emission spectrum, irrespective of the mode of operation. This provides the first step to the provision of reference samples to calibrate the transmission functions and detector sensitivities of all instruments so that they, in turn, may produce true electron emission spectra. This is vital if: (1) all instruments are to give consistent results; (2) theoretical terms are to be used in quantifying either AES or XPS; (3) reference data banks are to be established for AES or XPS.