Surface charge on poorly conducting thin films, a result of the emission of photoelectrons, had been considered an obstacle to measuring such samples, but researchers at Weizmann Institute of Science in Rehovot, Israel, see it as a means of measurement. Reporting in the July 27 issue of Nature, the team describes how a variant of x-ray photoelectron spectroscopy offers the ability to nondestructively analyze thin films.

The technique, which the researchers have called controlled surface charging, monitors changes in the energy of photoelectrons that are released when a sample is exposed to an electron flood gun. Demonstrating the approach on a multilayered sample, the team found that it could identify the depth and composition of the thin-film layers.