Enhanced Secondary Electron Emission in Nanoscale Thin Metal Containing MgO Film: Laser Irradiation on Creation of F Centers

Abstract

A number of oxygen vacancies were found in the MgO film when a nanoscale-metal embedded MgO film (MgO/nanoscale metal film/MgO) was exposed to a pulsed KrF excimer laser. This was due to the interfacial reaction between embedding nanoscale metal and MgO film. In a case of Nb embedding metal, the Nb(2)O(5) crystallites were evidenced to proceed the reaction at the MgO/Nb interface; 5MgO + 2Nb -> Nb(2)O(5) + 5Mg + 5V(O)(center dot center dot). The oxygen vacancies formed the F centers in the MgO bandgap, resulting in high cathodoluminescence intensity at the 431 and 526 rim region, corresponding to F(+) and F centers. The F centers in MgO played a role in increasing secondary electron emission coefficient (gamma). As several kinds of nanoscale metals for creating F centers (Cr, Ti, V, In, Ta, and Nb) were embedded into MgO film, the gamma values were found to be inversely linear with the Delta G(f) for the formation of metal oxides. The Nb embedded MgO film showed the highest gamma value of similar to 0.232 compared with normal MgO film (0.034).