Molecular Platform for Fast Low-Voltage Nanoelectromechanical Switching

Abstract

The use of molecules as active components to build nanometer-scale devices inspires emerging device concepts that employ the intrinsic functionality of molecules to address longstanding challenges facing nanoelectronics. Using molecules as controllable-length nanosprings, here we report the design and operation of a nanoelectromechanical (NEM) switch which overcomes the typical challenges of high actuation voltages and slow switching speeds for previous NEM technologies. Our NEM switches are hierarchically assembled using a molecular spacer layer sandwiched between atomically smooth electrodes, which defines a nanometer-scale electrode gap and can be electrostatically compressed to repeatedly modulate the tunneling current. The molecular layer and the top electrode structure serve as two degrees of design freedom with which to independently tailor static and dynamic device characteristics, enabling simultaneous low turn-on voltages (sub-3 V) and short switching delays (2 ns). This molecular platform with inherent nanoscale modularity provides a versatile strategy for engineering diverse high-performance and energy-efficient electromechanical devices.

Toward Practical Single‐Molecule/Atom Switches

“…Using molecules as length-controllable nano springs, Han et al, reported the design and operation of a nanoelectromechanical switch that overcomes the typical challenges of high actuation voltages and slow switching speeds. [303] The molecular distance between the upper and lower electrodes can be efficiently changed by electrostatic mechanical force by applying different biases and substituting molecular systems with varying chain lengths. This allows the switching between high and low conductivity states.…”

Directed Assembly of Nanomaterials for Making Nanoscale Devices and Structures: Mechanisms and Applications

“…The continuous miniaturization of CMOS field-effect transistors (FETs) faces challenges related to off-state current leakage and power dissipation . NEM switches have attracted attention in recent years due to their merits of near zero off-state current, steep subthreshold slopes, and robustness in extreme environments. − Han et al fabricated NEM switches using DEP assembled gold nanorods as active components (Figure a). Single gold nanorods were bridged between a pair of gold electrodes with self-assembled molecular spacers between the nanorod and electrodes.…”

“…(a) Fabrication of NEM switches using DEP assembled gold nanorods as active components. Reprinted with permission from ref ( 448 ). Copyright 2021, American Chemical Society.…”

Elucidating the effect of spin crossover materials on graphene sensing devices

“…An important bottleneck in molecular electronics applications is their considered limited speed capabilities when compared to standard semiconductor device technologies. Even though a few reports of fast switching molecular devices can be found in the literature 14,15 , their integration into scalable circuitry remains elusive. The switching of SCO materials can occur at the ns time scale when their size is reduced down to the nanoscale, at which one can still take advantage of the molecules collective behavior.…”