A novel triode-type carbon nanotube field emission micro-cathode fabricated by using electrochemical and micromachining

We report here an effective method for the fabrication of a large number of carbon nanotube (CNT) triode-type micro-cathodes. Our technique combines composite electroplating and micromachining, avoiding the tedious direct growth and the screen-printing procedures conventionally used to fabricate such structures. The emitter structure is characterized by uniform diameters and heights, as well as by high mechanical stability. In the structure, the leakage current to the gate can be reduced to near zero by coating the polysilicon on the gate. Field emission testing results show that the micro cathodes have quite good field-emission properties such as high current density (15mA/cm
²
at an applied electric field of 12Vμm-1), low turn-on field (2.4 V/μm), and good stability (109 h for 10% degradation of current density from 400μA/cm
²
).