A new type on-chip electron source based on electroformed SiO_x is recently reported to show dense and efficient electron emission under low working voltage. Here we study the effect of the Si doping type of SiO_x/Si substrate on the performances of the SiO_x-based electron source fabricated on it. The electron source is composed of an array of parallelly integrated micro-emitters. Each micro-emitter is composed of a square nanogap with a width about 100 nm which is spaced by two concentric graphene films on the SiO_x substrate. The inner graphene film contact with bottom Si electrode through a via hole opening to the bottom Si layer and the outer graphene film contact with the common metal electrode. Effective emission current and efficiency of the electron source are found to be significantly influenced by both the polarity of the driven voltage applied between the metal electrode and bottom Si layer and the polarity of the Schottky barrier at graphene-Si contact. The performances of electron sources can be optimized by choosing n-type doping of SiO_x/Si substrate to make the positive influence of the two aspects achieved at the same time. An emission current up to 100 μA and emission density of 250 mA cm⁻² are achieved for an optimized device with 64 micro-emitters at bias voltage of 32.8 V.

最近报道了一种基于电铸 SiO _x的新型片上电子源，在低工作电压下显示出密集而高效的电子发射。在这里，我们研究了 SiO _x /Si 衬底的 Si 掺杂类型对在其上制造的 SiO _x基电子源性能的影响。电子源由平行集成的微发射器阵列组成。每个微发射极由宽度约为 100 nm 的方形纳米间隙组成，该纳米间隙由 SiO _x上的两个同心石墨烯薄膜隔开基质。内层石墨烯薄膜通过通向底部硅层的通孔与底部硅电极接触，外层石墨烯薄膜与公共金属电极接触。发现电子源的有效发射电流和效率受到施加在金属电极和底部 Si 层之间的驱动电压的极性以及石墨烯-Si 接触处的肖特基势垒极性的显着影响。通过选择SiO _x /Si衬底的n型掺杂，可以优化电子源的性能，同时实现两方面的积极影响。发射电流高达 100 μ A，发射密度为 250 mA cm ^-2 在 32.8 V 偏置电压下实现了具有 64 个微发射极的优化器件。