MECHANISM OF CHANGE IN THE EMISSION AND OPTICAL PROPERTIES OF W AND Mo AFTER BOMBARDMENT WITH LOW-ENERGY IONS

The paper reports the results of study of composition, emission, and optical properties of polycrystalline W and Mo samples implanted with Ba+ ions and coated with submonolayer Ba atoms by applying Auger electron spectroscopy, secondary electron emission coefficient sigma technique, as well as the photoelectron quantum yield Y. The experimental part was carried out by using the instrumentation and under vacuum P approximate to 10(-6) Pa. It is shown that during the implantation of Ba ions in the surface layers of refractory metals, a mechanical mixture of the W + Ba and Mo-Ba types is formed. It has been established that the values of the coefficient of secondary electron emission s and the quantum yield of photoelectrons Y at the same value of the work function e phi in the case of implantation of Ba+ ions are much larger than in the case of deposition of atoms. The obtained experimental results are substantiated by theoretical calculations.