Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films
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- 作者：Farnaz Niroui ; Annie I. Wang ; Ellen M. Sletten ; Yi Song ; Jing Kong ; Eli Yablonovitch ; Timothy M. Swager ; Jeffrey H. Lang ; Vladimir Bulovi膰
- 刊名：ACS Nano
- 出版年：2015
- 出版时间：August 25, 2015
- 年：2015
- 卷：9
- 期：8
- 页码：7886-7894
- 全文大小：488K
- ISSN：1936-086X
文摘
Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a 鈥渟quitch,鈥?which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on鈥搊ff ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal鈥搈olecule鈥揼raphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications.