Preliminary study of KCl by field-emission microscopy

Small projections of KCl grown on the tungsten substrate from the saturated solution were observed by field-emission microscopy in an ultrahigh vacuum. The observed fieldemission patterns consisted of many bright spots with different sizes and brightness, and some of the bright spots repeated periodically disappearance and reappearance under the application of a constant voltage at lower temperatures. The spots increased in number and in brightness as the applied voltage and the substrate temperature were increased. A phenomenon which seems to be a kind of vacuum arc was frequently observed with a periodicity and its period was found to decrease with increasing the applied voltage.