Development of Low Energy Cathodoluminescence System and its Application to the Study of ZnO Powders

Abstract

AbstractWe have developed a cathodoluminescence (CL) system with high spatial resolution using a thermal-field emission gun operating with low electron beam energies. Since the electron range is proportional to the 1.7th power of the electron beam energy, operation with a low energy electron beam strongly reduces the probe size of CL. Luminescence property of ZnO tetrapods was studied with this system. High spatial resolution better than 100 nm was achieved when it was operated with a beam energy less than 3 keV. The variation of CL spectra along one leg of tetrapod was recorded. The ratio of the ultraviolet emission to the visible luminescence at the center of tetrapod was different from those of the points along the arm, suggesting that the center of tetrapod is much defective compared with the arms. We also observed a decrease of CL intensity during observation. Possible degradation mechanisms were discussed.