Zhao Zijun C, McKenzie David R
School of Physics, The University of Sydney, NSW 2006, Sydney, Australia.
Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, The University of Sydney, NSW 2006, Sydney, Australia.
Sci Rep. 2017 Oct 6;7(1):12772. doi: 10.1038/s41598-017-13028-5.
The tunnelling of electrons through barriers is important in field emission sources and in interconnects within electronic devices. Here we use the analogy between the electromagnetic wave equation and the Schrodinger equation to find potential barriers that, when added before an existing barrier, increase the transmission probability. A single pre-barrier of negative potential behaves as a dielectric "antireflection coating", as previously reported. However, we obtain an unexpected and much greater enhancement of transmission when the pre-barrier has a positive potential of height smaller than the energy of the incident electron, an unfamiliar optical case, corresponding to media with superluminal phase velocities as in dilute free electron media and anomalous dispersion at X-ray frequencies. We use a finite difference time domain algorithm to evaluate the transmission through a triangular field emission barrier with a pre-barrier that meets the new condition. We show that the transmission is enhanced for an incident wavepacket, producing a larger field emission current than for an uncoated barrier. Examples are given of available materials to enhance transmission in practical applications. The results are significant for showing how to increase electron transmission in field emission and at interconnects between dissimilar materials in all types of electronic devices.
电子隧穿势垒在场发射源和电子器件内部的互连中具有重要意义。在此，我们利用电磁波方程与薛定谔方程之间的类比关系，来寻找在现有势垒之前添加时能增加透射概率的势垒。如先前报道的那样，单个负电势的前置势垒表现为一种介电“抗反射涂层”。然而，当前置势垒具有小于入射电子能量的正电势时，我们获得了意想不到且更为显著的透射增强效果，这是一种不常见的光学情形，类似于稀薄自由电子介质中超光速相速度以及X射线频率下反常色散的介质情况。我们使用时域有限差分算法来评估通过带有满足新条件的前置势垒的三角形场发射势垒的透射情况。我们表明，对于入射波包，透射得到增强，产生的场发射电流比未涂覆势垒时更大。文中给出了在实际应用中可用于增强透射的材料示例。这些结果对于展示如何在所有类型电子器件的场发射以及不同材料之间的互连中增加电子透射具有重要意义。
