Low Energy Ion‐Electron Luminescence: A New Technique for the Excitation of Inorganic Phosphors

Abstract

A new technique for the excitation of inorganic phosphors by low kinetic energy ions (<40 eV) and low kinetic energy electrons (<20 eV) has been demonstrated and characterized. The characteristic light output of the phosphor has been used as a probe of the excitation mechanism. An empirical relationship between the light output and the ion and electron currents has been determined and used to ascertain the change in light output as a function of ion and electron kinetic energy and ionization potential. The excitation mechanism starts with the formation of holes by the ion beam. Although the holes are mobile in the lattice, some of the holes get trapped. In a second step electrons interact with these trapped holes to create an excited state (s) of the phosphor. Energy is transferred to the luminescent centers resulting in the characteristic emission of the phosphor. The slow or rate‐limiting step in the production of light by low energy ions and electrons is the emission of light. Of the ten phosphors examined for low energy ion‐electron excitation, six showed detectable levels of light output and, hence, we conclude that this excitation technique is quite general. The efficiency of light production observed for is ∼1 photon per 40 ions and no effort has been made to increase this efficiency. We refer to the light produced by this excitation technique as low energy ion‐electron luminescence (LEIEL).