C1s regions for polymers can often have acquisition times of Different polymers have different degradation rates.Some polymers are sensitive to prolonged X-ray exposure.Particularly useful in cases where C1s XPS data cannot easily distinguish between.Acquisition of valence band can be useful for “fingerprint” identification of polymers.Polymers Binding energies of common chemical states: Inelastic scatter of electrons through the adventitious carbon layer may cause a largeĬhange in background shape when compared with the spectrum from a clean sample.For example, the Na1s peak (binding energy=1071eV) may be weaker thanĮxpected, or completely disappear, but the Na KLL peak (binding energy=497eV).The intensity of higher binding energy peaks may be reduced relative to their.Quantification may be inaccurate when using peaks of significantly different energy.On native oxide of aluminium appears at ~286eV).Ī few nanometers of adventitious carbon on a sample can dramatically affect the survey Not always a valid charge reference value (e.g.The C-C component may be set to a binding energy of 284.8eV, by default.C1s spectrum for contamination typically has C-C, C-O-C and O-C=O components.Prevent/minimize chemical damage to the underlying material.Īdventitious carbon contamination is commonly used as a charge reference for XPS spectra. Use lowest energy argon beam available (e.g.Adventitious carbon may be removed by argon sputtering.(Typically with a layer thickness of 1-2nm.)
Most samples that have been exposed to the atmosphere will have a detectable quantity ofĪdventitious carbon contamination.Carbonates and Carbides)Īdventitious Carbon Contamination Binding energies of common chemical states:Ĭharge referenced to adventitious C1s, C-C peak at 284.8eV Experimental Information