Physics Department "E. R. Caianiello", University of Salerno, via Giovanni Paolo II n. 132, Fisciano 84084, Italy.
Nanoscale. 2019 Jan 23;11(4):1538-1548. doi: 10.1039/c8nr09068h.
We report the first observation of a gate-controlled field emission current from a tungsten diselenide (WSe2) monolayer, synthesized by chemical-vapour deposition on a SiO2/Si substrate. Ni contacted WSe2 monolayer back-gated transistors, under high vacuum, exhibit n-type conduction and drain-bias dependent transfer characteristics, which are attributed to oxygen/water desorption and drain induced Schottky barrier lowering, respectively. The gate-tuned n-type conduction enables field emission, i.e. the extraction of electrons by quantum tunnelling, even from the flat part of the WSe2 monolayers. Electron emission occurs under an electric field ∼100 V μm-1 and exhibits good time stability. Remarkably, the field emission current can be modulated by the back-gate voltage. The first field-emission vertical transistor based on the WSe2 monolayer is thus demonstrated and can pave the way to further optimize new WSe2 based devices for use in vacuum electronics.
我们首次观察到了由化学气相沉积在 SiO2/Si 衬底上合成的二硒化钨 (WSe2) 单层的栅控场发射电流。在高真空下，Ni 接触的 WSe2 单层背栅晶体管表现出 n 型传导和漏极偏压相关的转移特性，分别归因于氧/水的解吸和漏极诱导肖特基势垒降低。栅极调谐的 n 型传导使得电子通过量子隧穿被提取出来，即使是从 WSe2 单层的平坦部分。电子发射发生在约 100 V μm-1 的电场下，并且表现出良好的时间稳定性。值得注意的是，场发射电流可以通过背栅电压进行调制。因此，首次展示了基于 WSe2 单层的场发射垂直晶体管，这为进一步优化基于 WSe2 的新型器件在真空电子学中的应用铺平了道路。
