X-ray excited current from solid surfaces measured by using a STM apparatus

Irradiation of X-ray to solid surfaces causes photoelectron and Auger electron emission from the surfaces. We detected the X-ray excited current from a tip specimen using a scanning tunneling microscope (STM) apparatus for the first time. It was found that the current was amplified by ionization of the gaseous atoms and molecules present in the atmosphere. The dependence of the excited current on the irradiated X-ray intensity, gas pressure, kinds of gases and kinds of solids has been investigated. (author)