Fragments of known composition, such as H +, CH 3 +, Na +, H-, C-, O-and OH-were used for mass calibration and carefully checked these peak shapes did not have any charging effect. Methods employed with good success here at Surface Science Western include mounting samples on non-conductive double sided tape or mounting on glass slides. Charge compensation was achieved using a pulsed electron flood source. This "specimen isolation" technique is similar to that used in secondary ion mass spectrometry and effectively makes the entire sample (both insulating, semi-conductive and conductive areas) behave non-conductively. One excellent way to combat differential charging effects is to electrically isolate (or "float") the entire sample from the specimen holder. Must be understood or erroneous assignment of chemical states may result. All of this can result in changes in selected peak positions that A multilayered system may include alternating layers ofĬonducting, semi-conducting and insulating species in a variety ofĬombinations. The thin oxide layer on a metallic (conducting) materialĬan behave as a conductor, as a semi-conductor, or as an insulator as the film
Layered structures may alsoĬharge differentially. Spectra may be broadened significantly as a result. Semi-conductors and their conductivity varies with thickness. This may be complicated if the islands or domain structures behave as Neutralizer whereas the spectral features of the underlying material will notīe shifted. Will be shifted to lower binding energies by the action of the charge It is possible to imagineĪ sample with insulating domains or island structures that have varying Phenomenon known as differential charging can occur. Or layers of the sample being conducting or semi-conducting. Some cases only a portion of the sample is insulating with some discrete areas