# Staff Profile

## Dr Daniel Naylor

- Email: daniel.naylor@ncl.ac.uk
- Address: C.20, First Floor,

Herschel Annex

School of Mathematics, Statsistics and Physics,

NE1 7RU

**Note: I have now left the University.**

I am currently a Research Associate working with Angela Dyson in the School of Mathematics, Statistics and Physics. For more details of my current research, see the Research section of my profile.

I graduated with my BSc (Hons) in Physics with Lasers and Photonics in 2008 and my PhD at the University of Hull in 2012. My PhD was a theoretical and simulation based study of negative effective mass states in electron transport in Gallium Nitride. After a short postdoctoral research assistant post to start the investigation into the effect of hot phonons, I joined Tessella as a Software Consutant in 2013, which involved me working with a major multinational phamacutical and consumer goods company on analytics and scientific software products.

I returned to the University of Hull in 2015 as a Research Associate to investigate confined phonons, and joined Newcastle University in July 2017 to continue that role. In October 2017, I was appointed as a temporary lecturer for a year to cover for a member of staff on sabbatical where I taught on various courses within Physics and Engineering, before returning to my role as a RA in October 2018 to continue my investigation into confined phonons.

I am a member of the Institute of Physics and a Fellow of the Higher Education Academy.

My current research concerns the effect of nanoscale structures, such as quantum dots and heterostructures, on phonons, or packet of vibrations, and their subsequent effect on electron-phonon interactions.

At present, the model of choice for investigating the confinement of phonons is the Dielectric Continuum (DC) model, which uses electromagnetic boundary conditions to determine the form of the phonons. Its popularity stems from the ability to predict the electron scattering rates accurately for many quantum systems, however it breaks down when used with structures smaller than around 10nm. It is also unable to predict the form of the modes that would be seen using Raman spectroscopy. This is due to the lack of mechanical boundary conditions in the model.

My work uses the Hybrid model, pioneered by Ridley and Babiker, to investigate these phonon modes. The model includes the mechnical boundary conditions and postulates that, in nonscale structures, different phonon modes mix, or hybridise. This means that while the individual confined phonon modes may not appear to obey the laws of quantum confinement, the hybrid formed by their superposition does. Such a mode will correctly predict the electron-phonon interaction at the smaller sizes that the DC model cannot, as well as produce modes that can be verified by Raman spectroscopy due to the imposition of the mechanical boundary conditions.

I also develop Monte Carlo codes for semiconductor transport. I have previously developed a code that investigates the effect of electron negative effective mass in the transport properties of GaN, assisted in an extension of the code to investigate hot phonons and assisted in the developement of a planar 1D Gunn diode simulation.

I have also assisted in the investigation into an HSPICE model that enables the investigation of SiC JFETs at a range of temperatures using a single model.

I am a Fellow of the Higher Education Academy.

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In 2020/2021, I teach on the following modules:

PHY2029: Introduction to Scientific Python

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In 2017/2018, I taught on the following modules.

EEE2015: Electromagnetic Fields & Waves

PHY2021: Principles of Electromagnetism

SPG8024: Quantifying Energy Decision Making

- Naylor DR, Dyson A, Ridley BK. Dispersion and the electron–phonon interaction in a single heterostructure.
*Physica E: Low-dimensional Systems and Nanostructures*2017,**86**, 218-224. - Dyson A, Naylor DR, Ridley BK. Hot-Phonon Effects on High-Field Transport in GaN and AlN.
*IEEE Transactions on Electron Devices*2015,**62**(11), 3613-3618. - Naylor DR, Dyson A, Ridley BK.
**Steady state and transient electron transport properties of bulk dilute GaN**._{x}As_{1-x}*Journal of Applied Physics*2012,**111**(5), 053703. - Naylor DR, Dyson A, Ridley BK.
**Steady-state and transient electron transport in bulk GaN employing an analytic bandstructure**.*Solid State Communications*2012,**152**(6), 549-551.