Browsing by Subject "Partial neutralization"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Charging / discharging of thin PS / PMMA films as probed by dynamic x-ray photoelectron spectroscopy
    (2007) Sezen, H.; Ertas, G.; Dâna, A.; Süzer, Şefik
    Polystyrene / polymethyl methacrylate (PS-PMMA) thin films were analyzed for detecting phase separation as well as probing their electrical responses by XPS. It was also shown that electrical parameters like resistance or capacitance can also be extracted using dynamical XPS measurements. A Kratos ES300 electron spectrometer was used for XPS measurements, and a nearby filament provided low-energy electrons for charge neutralization. The results show that under a positive stress, low-energy electrons are attracted to the sample and yield less positive charge on the sample, due to partial neutralization.
  • Thumbnail Image
    ItemOpen Access
    Differential charging in SiO2/Si systems as determined by XPS
    (American Chemical Society, 2004) Karadas, F.; Ertas, G.; Süzer, Şefik
    The Si2p binding and the SiKLL kinetic energy difference between the SiO2 layer and Si substrate is shown to be influence by application of external voltage bias to the sample holder due to the differential charging as was already reported earlier (Ulgut, B.; Suzer, S. J. Phys. Chem. B 2003, 107, 2939). The cause of this bias induced (physical)-shift is now proven to be mostly due to partial neutralization by the stray electrons within the vacuum system by (i) introducing additional stray electrons via a filament and following their influence on the measured binding energy as a function of the applied voltage, (ii) measuring and Auger parameter. It is also shown that citrate-capped gold nanoclusters deposited on the SiO2/Si system experience differential charging similar to that of the oxide layer rather than the silicon substrate.