Chang Wen-Teng, Cheng Ming-Chih, Chuang Tsung-Ying, Tsai Ming-Yen
Department of Electrical Engineering, National University of Kaohsiung, Kaohsiung 811, Taiwan.
Nanomaterials (Basel). 2020 Nov 29;10(12):2378. doi: 10.3390/nano10122378.
Field emission air-channel (FEAC) devices can work under atmospheric pressure with a low operation voltage when the electron channel is far less than the mean free path (MFP) in the air, thereby making them a practical component in circuits. Forward and reverse electron emissions of the current FEAC devices demonstrated symmetric Fowler-Nordheim (F-N) plots owing to the symmetric cathode and anode electrodes. This research aimed to demonstrate the arithmetic application of the FEAC devices, their substrate effect, and reliability. A voltage adder was composed of two FEAC devices whose two inputs were connected to two separate function generators, and one output was wire-connected to an oscilloscope. The devices were on a thin dielectric film and low-resistivity silicon substrate to evaluate the parasitic components and substrate effect, resulting in frequency-dependent impedance. The results show that the FEAC devices possessed arithmetic function, but the output voltage decreased. The FEAC devices were still capable of serving as a voltage adder after the reliability test, but electric current leakage increased. Finite element analysis indicated that the highest electrical fields and electron trajectories occur at the apices where the electrons travel with the shortest route less than the MFP in the air, thereby meeting the FEAC devices' design. The modeling also showed that a sharp apex would generate a high electric field at the tip-gap-tip, enhancing the tunneling current.
场发射空气通道（FEAC）器件在电子通道远小于空气中的平均自由程（MFP）时，能够在大气压下以低工作电压工作，从而使其成为电路中的实用组件。由于阴极和阳极电极对称，当前的FEAC器件的正向和反向电子发射呈现出对称的福勒-诺德海姆（F-N）曲线。本研究旨在展示FEAC器件的算术应用、其衬底效应和可靠性。一个电压加法器由两个FEAC器件组成，其两个输入连接到两个独立的函数发生器，一个输出通过导线连接到示波器。这些器件置于薄介电膜和低电阻率硅衬底上，以评估寄生元件和衬底效应，结果呈现出频率相关的阻抗。结果表明，FEAC器件具有算术功能，但输出电压降低。经过可靠性测试后，FEAC器件仍能用作电压加法器，但漏电增加。有限元分析表明，最高电场和电子轨迹出现在顶点处，电子在这些顶点处以小于空气中MFP的最短路径行进，从而符合FEAC器件的设计。该建模还表明，尖锐的顶点会在尖端-间隙-尖端处产生高电场，增强隧穿电流。
