Improvement of a number of active tips and emission measurements from individual tips in volcanostructured Spindt-type field emitter arrays

We developed an electron optical instrument for evaluating multi-emitters. This device enables us to evaluate both the percentage of active tips and the stability of the emission current from each active tip. Herein, we employed the instrument to observe a volcano-structured Spindt-type field emitter array (FEA) in the photoelectron emission microscopy (PEEM) and field electron emission microscopy (FEEM) modes. Furthermore, we measured the emission current from each active tip in the FEA. Consequently, we found that the number of active tips in the FEA can be considerably increased by aging at a relatively high voltage.