Dr Jessica Boland of the University of Oxford

Dr Jessica Boland of the University of Oxford, who has developed novel techniques for characterising the charge carrier dynamics of doped semiconductor nanowires and demonstrated novel nanowire-based terahertz devices, such as ultrafast optically switchable terahertz modulators for ultrafast wireless communication.

Jessica Boland has developed a novel technique based on terahertz spectroscopy for accurate characterisation of doping densities and activation energies in semiconductor nanowires, which has enabled the nanowire carrier dynamics in doped nanowires to be examined.

She has shown an enhancement of photoconductivity lifetime by more than a factor of two for shell-doped gallium-arsenic nanowires, as a direct result of doping-engineered bandbending. This is crucial for the implementation of nanowires in devices that require long carrier lifetimes – particularly solar cells. By modulation doping these nanowires, she has also shown that it is possibly to avoid the inherent reduction in carrier mobility associated with increased impurity scattering due to doping.

Boland has demonstrated high electron mobility, comparable to an undoped reference, by physically separating the donor ions from photoexcited electrons. She has also shown that incorporating antimony in indium-arsenic nanowires can lead to an increase in both carrier lifetime and carrier mobility due to a reduction in crystal defect density.This is a crucial result for the field, as it offers another way of tailoring nanowire optoelectronic properties for implementation in electronic devices. Finally, she has also demonstrated prototype nanowire-based terahertz devices.

Via terahertz measurements, Boland has helped show that single-nanowire indium-phosphorous terahertz detectors can be developed with comparable performance to bulk receivers, with a high signal-to-noise ratio of 40 and broad detection bandwidth of greater than 2 THz. She has also demonstrated an ultrafast optically switchable terahertz polariser based on gallium-arsenic nanowires, which performs comparably to graphene-based modulators, yet surpasses carbon-nanotube polarisers.

Alongside her research, Boland has been active in physics outreach, acting as a coordinator for the Early Academic Career Outreach Network at the University of Oxford and organising outreach events for local schools. She also acts as an outreach assistant for numerous Oxford colleges and as an Ogden Trust careers adviser, and is developing a podcast series looking at the person behind the scientist, as well as developing science workshops for hearing-impaired students.