Speaker
Mr
Jamie O D Williams
(Department of Physics and Astronomy, University of Leicester)
Description
Graphene offers great potential as a technology for fast photodetectors due to its unique electronic characteristics, which include very high carrier mobility, and sensitivity of its conductivity to external doping. We begin by reviewing the state of the art of graphene research, including fundamental research, graphene synthesis, manufacturing processes used to develop devices, and research into applications. We then describe the development of within this project of two graphene-based detectors: a terahertz detector capable of detecting 1.2THz, and an X-ray detector aimed at single photon sensitivity, both designed for operation at room temperature.
There is high demand for fast, broadband terahertz photodetectors in a wide range of fields including space communications, security and imaging in both commerce and scientific research. We report on the development of a totally passive graphene-based broadband terahertz detector utilizing the Dyakanov-Shur effect [1] [2]. The device, which is based around a graphene field effect transistor geometry, generates an intrinsic photovoltage on illumination with THz radiation with no requirement for a drain-source voltage. We present a theoretical study of the detector response and use simulation software to design and optimise the detector antennae. We present our latest experimental results obtained using broadband pulsed and tunable cw laser sources, including estimates of the sensitivity of the device. We propose routes to further improve sensitivity and discuss the scope for narrowband THz detectors, and arrays of detectors for imaging, at frequencies where such technology is not readily available.
We also report on developments towards a fast, simple and cheap to manufacture single X-ray photodetectors that utilises the field effect and operates at room temperature, and could have applications in fields such as space sciences and medical imaging. The device, which is based around a graphene field effect transistor geometry, generates charge carriers in the absorber that result in a measurable change of conductivity of the graphene channel [3] [4] [5]. We consider the absorber dynamics and transport properties of the graphene to design our detector, and present our experimental results obtained using a pulsed optical laser source and low intensity Fe-55 source at 5.9 keV to probe the energy sensitivity of the detector. We propose routes to further improve sensitivity and SNR by iterating the detector design and geometry, and discuss the scope for arrays of detectors for imaging.
Short Speaker Information
Jamie Williams is a final year PhD student at the University of Leicester. He gained a Masters in Physics with Theoretical Physics from the University of Manchester in 2013, before taking up a PhD studentship at the University of Leicester to develop graphene-based photodetector technologies with Professor Jon Lapington in the High Speed Imaging group. Jamie’s PhD research programme is investigating potential graphene-based technologies for low intensity photon counting detectors covering the energy range from THz to X-rays
| CONTRACT FRAME (ARTES, ITI, TRP, GSTP, NPI, ...) | GSP |
|---|---|
| BUDGET (k€) | 100 |
| ENTITIES (Including country) | Department of Physics and Astronomy, University of Leicester (UK) |
| Proposed Duration | 40' |
Primary authors
Mr
Ian B Hutchinson
(Department of Physics and Astronomy, University of Leicester)
Mr
Jamie O D Williams
(Department of Physics and Astronomy, University of Leicester)
Mr
Jon S Lapington
(Department of Physics and Astronomy, University of Leicester)
Mr
Mervyn Roy
(Department of Physics and Astronomy, University of Leicester)
