Low voltage, high resolution SEM imaging for mesoporous materials

Abstract

Mesoporous silicas (MPSs), which possess highly ordered structures with a pore size of 2–15 nm, must be widely applied to catalysts, adsorbents, membranes, and sensors. Direct SEM observation of MPSs provides detail information on the external and internal structures, though it consistently faces charge-up problems of insulating silica frameworks. Several skills such as choosing low resistance substrate or replica method succeed to avoid charge-up phenomena [1]. In this contribution, high resolution, direct SEM imaging of MPSs is tried under the condition of low voltages. A cold FEG SEM, which employs the snorkel type objective lens, retarding device [2] and E cross B (ExB) filter [3] for detecting secondary electron (SE) are used for this study.