Anodisation of gridded silicon field emitter arrays

Field emission characterisation of gridded silicon FEAs was carried out before and after anodisation. Each sample contains ten gridded FEAs with array sizes varying from I to 10x10. For each sample, both current-voltage and current-time measurements of each FEA were carried out before and after arzodisation. The morphology and thickness of the porous silicon layer on the emitters were controlled by the anodising current density and duration of the anodisation process. The emission uniformity of FEAs was evaluated by comparing the I-V curves from different FEAs, which show that the emission uniformity had been improved after anodisation. In addition, the I-t measurements show that the emission stability of FEAs is very sensitive to anodisation time, and it is essential to use a very short anodisation time (similar to 0.1 second) to obtain stable emission currents. Under these conditions no adverse effects of the anodisation process on emission stability have been found whilst the improvements in operating voltage and uniformity are maintained