Silicon Oxide Based on-Chip Electron Sources

On-chip electron sources driven by electricity have been pursued by researchers for more than 60 years for their light in mass, compactness, being integratable, high energy- efficiency and fast response, etc. Thought many efforts have been devoted to them, the results are still unsatisfactory. Recently, we have proposed a new type of on-chip electron source based on electroformed silicon oxide between graphene films on silicon oxide1, which is named electron- emitting nanodiode (EEND). Electron emission from our devices is thought to be generated from horizontal tunneling diodes formed in electroformed silicon oxide. The EEND can be turned on by a voltage of ~7 V in ~100 ns and show an emission current of up to several microamperes, corresponding to an emission density of ~106 A/cm2 and emission efficiency as high as 16.6%. Since using semicondutor fabrication technolgy makes its fabrication very easy, an array of 100 EENDs is fabricated in an effective area of 82 μm ×18 μm and its emission current reaches 73.4 μA, which exhibits a global emission density of 5 A/cm2 and stable emission with negligible current degradation over tens of hours under a vacuum of ~5 × 10-6 Pa. Recent experiments show emission current increases linearly with the numbers of EENDs in an array, and emission current has reached to 1 mA. Combined advantages of high emission current and density, high emission efficiency, low working voltage, and easy fabrication make our on-chip electron sources promising in realizing miniature and on-chip electronic devices and systems based on free electron beams.