Porous silicon field emission arrays with built-in spacer

In this research, we applied the physical and electrical characteristics of porous silicon to enhance the performance of field emission devices. The surface of silicon field emitters have been modified by chemical etching with HF:HNO3:H2O solution, and electrochemical etching with HF:ethanol solution. The emitter surface became roughened and had nano-scale fibrils over the emitter surface in both cases. We found PS thin films prepared by chemical etching of Si field emitters also gave similar field enhancement effects as does electrochemically formed PS. Porous silicon contributed to the increase of the emission current, the reduction of operating voltage, the improvement of the uniformity of the emission characteristics between the emitters and the reduction of the probability of emitter failure during operation.