Photo-response measurements and temporal analyses of gated p-silicon field emitter array

Successful integration of gated field emitter arrays (FEAs) on p-Si substrates with an improved fabrication procedure that results in dramatically reduced leakage current to the gate is presented. Improved fabrication procedure enables a maximum anode-to-gate current ratio of 3300 and high photocurrent to dark current contrast. The dark current at 150 V is 6 μA, about 40 times less than an earlier device. I-V curve shows an abrupt transition from field emission to the supply-limited emission at around 50 V. A linear response of the photocurrent to optical power up to sub-milliamp range is achieved. Analyses show that sub-nanosecond response time is possible. These results show promising applications of gated FEA photocathodes in microwave tubes and electron accelerators.