Stiction-Free and Tuneable Nano-Electro-Mechanical Systems Incorporating Liquid Crystals

Lead Research Organisation: University of Southampton
Department Name: Optoelectronics Research Centre (ORC)

Abstract

Nano-electro-mechanical systems (NEMS) are integrated miniature devices that can sense or actuate on the nanoscale, while generating observable effects on the macroscale. They are beginning to shape into one of the key technologies of the 21st century, which has the potential to revolutionize both industrial and consumer products, transforming the way we live and work through a multitude of applications (ranging from displays, smart phones, portable electronics and computer peripherals to cars, medical diagnostics and therapy, metrology and navigation). However, nanoscopic mechanical motion underpinning the functionality of such systems is often affected by a number of parasitic effects and the chief among them is stiction - unintentional adhesion of moving parts leading to a catastrophic failure of the devices. Correspondingly, the ability to engage and control reliably mechanical movements in NEMS is the main challenge of the technology.

We believe that by combining NEMS with liquid crystals we can meet this challenge in a simple yet efficient manner and develop a new generation of NEMS - stiction-free hybrid nano-electro-mechanical systems, which will feature dynamically adjustable behaviour and field-programmable functions. Our approach exploits elastic distortions in liquid crystals coupled to nanoscopic mechanical motion in operating NEMS. By engaging transitions between various structural phases of liquid crystals and their susceptibility to a wide range of stimuli (i.e. heat, light, electric and magnetic fields) we will introduce a mechanism for tuning dynamically the response characteristics of the resulting hybrids and eliminate the need for additional integrated circuitry, thus, reducing the overall complexity and cost of the devices. A broad spectrum of structural transitions exhibited by liquid crystals (when confined at the nanoscale) should further enrich the behavior of such hybrid NEMS as actuators, sensors, relays, re-configurable metamaterials and plasmonic circuits, making the development of adaptive and 'smart' nanosystems a practical proposition.

Planned Impact

The proposed project offers strong technological impact by addressing current challenges and introducing new capabilities in the field of microsystems and, in particular, nano-electro-mechanical systems (NEMS). Given that NEMS technology is starting to occupy a central position in our daily life (think of smart phones, displays, cars, telecom and internet, heart pacemakers and hearing aids etc.), the successful outcome of our research program will provide the UK's relevant industries with a competitive advantage that will ultimately translate to improvement in the quality of life.

The project will also contribute directly to applied and fundamental sciences by

- providing a platform for engineering smart photonic media with strong nonlinearity, and dynamically and spatially tuneable optical properties;

- expanding our knowledge on mechanical behaviour and ordering of liquid crystals (LCs) at the nanoscale through systematic study and characterization of LC-NEMS hybrids;

- introducing a new exciting area of research, which interfaces elastic and mechanical response of soft and (structured) hard matter at the nanoscale.