Innovative Methods for a Deconvolution of XPS Spectra from Plasma-oxidized Polyethylene

X-ray photoelectron spectroscopy (XPS) has been used to study the chemical effects of oxygen plasma treatment on polyethylene films. A comparison of previous investigations shows that the simple deconvolution by curve-fitting leads to contradictory results. For a deconvolution we used innovative methods. The maximum entropy algorithm leads to a valid identification of chemical states. A proper consideration of the background shows that a linear background is not appropriate. For this reason, we used a model for an insulator loss function which was inspired by the loss function calculated from optical data. The model depends on four parameters which were included in the fitting process. The background calculation was performed according to the method of S. Tougaard and co-workers.