Silicon nanowire networks for the application of field effect phototransistor

A random network of silicon nanowires was synthesized on Si3N4/Si substrate via a catalytic reaction in N2 atmosphere at 1000 °C using a parallel plate structure. The nanowires were completely amorphous with an average diameter of 40-80 nm. A commercial high-brightness light emitting diodes was used as the light source in the gate of the field effect phototransistor. It was found that drain current was proportional to the light intensity. It is suggested that the current gain of the photoresponse under the red light illumination is smaller compared to that under the blue light illumination. The maximal current gain increases approximately 30 times under the blue light illumination.