The effect of emitter geometry on lateral field emission diodes fabricated by AFM-based electrochemical nanolithography

Lateral field emission diodes were successfully fabricated using atomic force microscopy (AFM)-based electrochemical nanolithography and tetramethyl ammonium hydroxide (TMAH) wet etching method. Field emission (FE) current of the silicon emitter cathode was measured as a function of the applied anode voltage under vacuum environment. For narrowed nanogaps from 55 to 35 nm, the turn-on voltage was decreased from 21 to 16 V. The turn-on voltage of the 35 nm gap was reduced from 16 to 8 V by changing the curvature radius of the cathode tip. The sharper emitter had the lowest turn-on voltage, largest field-enhancement factor, and good stability, which were attributed to the small emitter radius at the cathode tip and very slight changes in the local field factor. These results indicate that the diodes fabricated using this technique had the lowest value of turn-on voltage ever reported for lateral silicon FE devices.