Charge Patterning on Sapphire Studied by Electrostatic Force Microscopy

The ability of insulating materials to trap charges is a phenomenon of interest in many technological fields such as information storage, electron beam lithography and formation of electrets for instance. However, charge-trapping characteristics are not well understood in spite of a large amount of studies carried out mainly by scanning electron microscopy (SEM) [1,2] and more recently by atomic force microscopy (AFM) [3,4]. Whatever the field of application, several issues such as the formation, the accumulation and the stability of charges after injection into the material demand further investigations.