Professor of Low-Dimensional Electronics
Academic Division: Electrical Engineering
Telephone: +44 1223 7 48379
Email: hjj28@eng.cam.ac.uk
Research interests
Dr Joyce’s research aims to create nanoscale and low-dimensional components for future electronic and optoelectronic devices. These components include low-dimensional materials such as graphene, monolayer transition metal dichalcogenides (e.g. monolayer MoS2) and semiconductor nanowires.
Particularly promising are semiconductor nanowires made out of III–V materials, such as GaAs, InAs, InP and AlGaAs. These nanowires typically feature diameters between 10 to 100 nm and lengths of several microns. The excellent electronic properties of these III–V materials, coupled with the tiny dimensions of the nanowire geometry, make III–V nanowires outstanding candidates for future electronic and optoelectronic devices, including light emitting diodes, lasers and solar cells.
If nanoscale materials are to be useful in future devices, we need to be able (i) to fabricate them controllably and reproducibly using techniques such as chemical vapour deposition and molecular beam epitaxy, (ii) to measure and control their fundamental optical and electronic properties, and (iii) to develop processing techniques to make functional devices. Dr Joyce’s research endeavours to grow and characterise nanowires and other low-dimensional materials, and implement novel devices, particularly solar cell devices, based on these materials.
Strategic themes
Energy, transport and urban infrastructure
Development of new electronic and photonic devices that exploit the unique properties of nanomaterials.
Manufacturing, design and materials
Engineering new nanomaterials for electronics and photonics.
Research projects
Hannah is in receipt of an ERC Starting Grant (ACrossWire 716471).
A Cross-Correlated Approach to Engineering Nitride Nanowires
Semiconductor nanowire have outstanding potential for emerging applications in energy-efficient optoelectronics and solar energy harvesting. When tailored at the nanoscale, nanowires should overcome many of the challenges that face conventional planar semiconductors, and also add extraordinary new functionality to these materials. However, progress towards nanowire devices has previously been hampered by the challenges in quantifying nanowire electrical properties using conventional contact-based measurements. It is then extremely difficult to optimise nanowire growth in the absence of reliable electrical transport data. This project overcomes this problem through an unconventional approach to nanowire electrical characterisation: contact-free measurements. Growth studies and contact-free studies are being performed in parallel to provide unprecedented insight into the growth mechanisms that govern the electronic properties of nanowires. The key contact-free technique at the heart of this proposal is ultrafast terahertz conductivity spectroscopy: an advanced technique ideal for probing nanowire electrical properties. This synergy of noncontact studies and detailed growth studies is expediting rational, targeted development of nanowires and nanowire heterostructures with specified functionality. We are now applying our findings by tailoring nanowires as photoelectrodes for solar photoelectrochemical water splitting. This is an application for which nitride nanowires have outstanding, yet unfulfilled, potential. This project is a necessary step in harnessing the true potential of nanowires and bringing them to the forefront of 21st century technology.