Photoassisted electron emission from metal-oxide-semiconductor cathodes based on nanocrystalline silicon

Abstract

This paper investigates the effect of optical pulses on the electron emission properties of metal-oxide-semiconductor (MOS) cathodes based on nanocrystalline silicon (nc-Si). The emission current is enhanced by about two orders of magnitude by the irradiation of 405 nm laser light. The increase of the emission current under irradiation was proportional to incident laser power. The differential quantum efficiency of the nc-Si based MOS diode itself was estimated to be 3 × 10−2. However, the value of the photoemission current was only 3 × 10−7 due to the short mean free path of hot electron for Pt used as the gate electrode. We obtained a pulsed electron beam from the cathode device by a pulsed laser. The result shows that MOS type cathodes have a suitable structure for optically generating a train of short electron bunches.

Electron Emission Properties of Silicon-Rich Silicon Oxide Film Prepared by Reactive Magnetron Sputtering Deposition and Rapid Thermal Annealing

“…Planar cathodes based on nanocrystalline silicon (nc-Si) particles covered with thin oxide films were fabricated by pulsed laser ablation, and the energy distribution of emitted electrons and the emission uniformity of these cathodes were analyzed [18][19][20][21][22] . Nc-Si cathodes could generate optically modulated electron emission under pulsed laser irradiation 23 . The emission efficiency of field emission cathodes based on Si quantum dots formed by very-high-frequency plasma enhanced chemical vapor deposition were improved through the thickness optimization, and the annealing and thermal-oxidation treatment of nc-Si film 24,25 .…”