Scanning Force Microscopy (SFM) is a metrology method used for imaging and force sensing the microscopic world, capable of achieving spatial resolutions well below those possible with optical microscopes; therefore, it has been employed in many scientific and industrial applications. Indeed, this method has revealed to be of fundamental importance in life sciences, as it can be used to determine the properties at the scale of individual molecules. Many types of SFM exist (Atomic force microscopy (AFM) and Nanoindentation being two examples), but all have a broadly similar construction. A tiny needle (or probe) is mounted at the end of a flexible cantilever. The probe scans the surface of a sample, and the force interactions between the sample and the probe are used to infer information about the sample.
However, all these instruments present a major issue that is common to all SFM rigs: in order to provide an absolute measurement, the spring constant of the cantilever upon which the probe is mounted must be known. While many SFM manufacturers calibrate their cantilevers at time of their construction, there are many environmental factors that can cause the cantilever spring constant to vary over time: temperature, humidity and mechanical shocks can all cause drifts or tares in the cantilever values. Therefore, without a pre-measurement calibration, users may not know to what extent they could trust their measurements. This uncertainty undermines the results and may potentially lead to misleading outcomes with detrimental impact for the user, both scientifically and financially.
What is needed is a tool that can be used prior the measurements to re-calibrate the cantilever. This can be achieved via the use of microelectromechanical systems (MEMS): microscopic mechanical instruments machined from semi-conductor materials. Such devices are ubiquitous in 2020 – underpinning the technology of mobile phone accelerometer. By using a ‘mass-on-spring’ design, a miniaturised calibration device can be produced that will act like a common weight scale. As a force is applied to the MEMS device by means of the microscopic probe, the displacement of the mass will be measured using a precision capacitive readout, and a calibration of the cantilever spring constant will be calculated.
In this project you will work within a small team to develop this exciting new technology. This project offers an exciting opportunity to work in world leading research groups and labs. You’ll learn new skills and work collaboratively with a vibrant team of multidisciplinary researchers. You’ll get trained in nanofabrication in the JWNC. You’ll get to work with collaborators in industry and academia. You’ll receive a tax-free stipend, and you’ll get to travel internationally for meetings and conferences. You’ll be encouraged to work hard when at university, but encouraged equally to maintain a healthy work/life balance.
We’re looking for a new PhD student from a STEM background (with a 1st or 2:1 degree in engineering/physics etc.) Enthusiasm is essential, as well as a willingness to learn skills in many different areas of science and engineering.
A bit about the primary supervisor: Richard Middlemiss is a Royal Academy of Engineering research fellow. His last project produced a Nature paper, a patent, and many industrial and academic collaborations. He wants to widen participation in Engineering/Physics, because diverse teams produce better work. You won’t just be working with him, though – you’ll be working in a friendly group of researchers in the James Watt School of Engineering
To apply, please email Dr Richard Middlemiss ([Email Address Removed]) with a C.V and cover letter before the 20th January (though it is also fine to get in touch in advance if you have any informal questions). The successful candidate will be put forward for a funding scholarship. The PhD position is conditional on this funding application.
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