Graphene Micro-sensors for Adaptive Acoustic Transduction (GMAAT)

This project aims to develop novel acoustic transduction technology for use in hearing aids. The
key proposition is to use an ultra thin-film membrane (graphene) as the vibrating mechanical
component in a resonant gate transistor (RGT). Such a sensor will provide direct transduction of
acoustical vibrations in air, via vibrations of the membrane, to an electrical signal within the
underlying transistor. Main advantages of such an approach include adaptive gain control,
selective frequency tuneability, improved signal to noise performance over conventional
transducers and multi-channel scalability.

The proposed system, made using microelectromechanical systems (MEMS) fabrication
processes, also lends itself particularly well to direct incorporation within a wider integrated circuit
design that will provide both signal processing and real-time tuning and gain control capabilities.
Eventually, a fully integrated parallel system is proposed that will see an array of transducers, each
acoustically/mechanically/electrically tuned to a narrow portion of the auditory bandwidth and
capable of real-time gain and frequency response control.

Such a system will provide cochlea-inspired gain control and, where desired,
frequency selectivity at the point of transduction, leading to improved signal to noise
performance and opening up a range of novel signal processing possibilities.

Knowledge and People
The successful outcome of the programme will provide the research community in the UK with a crucial research knowledge base for the fabrication and characterisation of MEMS acoustic devices. The proposal brings together two elements of MEMS processing technology and acoustic devices design and testing, all aspects of which are internationally competitive. In particular, the application of the adaptive MEMS-transistor to hearing aid devices represents a first in the world and the unique combination of the recognised expertise provides immense opportunity for the UK to gain leadership in this area.

The collaboration between scientific colleagues at the Reid School of Music and School of Engineering will enable access to exploit the results when the opportunity arises, by interacting with the University's research and innovation initiative (ERI). The collaborative work between scientific colleagues, will be of great benefit to the post-docs involved as the project will enable them to develop interdisciplinary skills and address exciting scientific and technical challenges in the process. Moreover, it is envisaged that the research team will join the LLHW Hearing Aid Research Network in order to promote cross-fertilisation of ideas and concepts perhaps currently lacking in the proposal that is associated with end user needs of the proposed research. To this end, we have made initial contact with Dr Michael Stone, who will be submitting a LLHW Hearing Aid Research Network bid.

Economy and Society
The hearing aid market is an economically significant and expanding sector. The worldwide hearing aid market was reported to be worth around 5.4 billion USD in 2012, while the UK market share of hearing aids was more than 600 million Euros in 2011. The worldwide sector is dominated by six companies, who together owned around 98% of the market in 2012. The success and ongoing expansion of the sector mean that new and disruptive technologies are going to be in demand by all the large manufacturers. A key growth area is likely to be in personalised hearing prosthetics that perform better within noisy listening environments. The opportunites opened up by our proposed novel transduction technology in these areas could see it ready for use within real devices within the next 5-10 years. We view our potential involvement in the present call as being a key step along this pathway to impact, providing us with unique collaboration and engagement opportunities with clinical and industrial partners, by joining the LLHW Hearing Aid Research Network.

Hearing loss affects more than 10 million people in the UK. With an increasingly older population, its societal impacts are likely to grow. The UK currently performs quite well in the use of hearing prosthetics, relative to the rest of the EU, with a 35.3% uptake rate in 2010. The objective of all researchers working in the auditory sciences is to improve the hearing of hearing impaired listeners, and facilitate greater use of hearing technology by those in society that are yet to experience its benefits. We are proposing to develop a novel transduction technology that may be applicable to a range of current and next-generation hearing aid designs. Ultimately, the proposed research is targeted at the improvement of hearing aids, leading to improved quality of life for users. The research will lead to exciting opportunities for adopting novel, personalised sound transduction and signal processing strategies that will address individual hearing problems, provide improved speech-in-noise performance and be adaptable over time to our ever changing needs.