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Centre for Doctoral Training in Photonic Integration and Advance Data Storage

Nicholas Stephen

Educational Background and Experience: BSc Honours in Chemistry (2018) and MSc in Biostatistics (2019), both from the University of Glasgow. 

CDT PhD Project:
Title: Investigating GaAs metamorphic lasers. 

Supervisors: Dr Miryam Arrendondo-Arechavala (Queen’s University Belfast) and Dr Emanuele Pelucchi (Tyndall National Institute) 
Project description: 
Metamorphic growth is a technique where a virtual buffer layer is grown on a substrate such as GaAs.  The lattice constant of the buffer layer can be tailored, which enables the growth of a laser heterostructure that can be tuned to different applications including telecommunication. This project in collaboration with the Tyndall National Institute in Cork is investigating several different metamorphic lasers grown by Metalorganic Vapour Phase Epitaxy, MOVPE. Using techniques such as Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy, the aim of the project is to investigate the internal structure of the lasers further to find out more on defects, strain and chemical composition. The information obtained will help to optimise the manufacturing process with the aim of producing a laser that is viable for commercial telecommunication applications. 

General Research/Science Interests:
What I enjoy most about science is that research done can have a positive impact and that you will always discover new things. From the time spend on my project, I have learned a lot about metamorphic lasers and techniques required to prepare samples for electron microscopy such as mechanical preparation and the more common Focussed Ion Beam microscopy. My project has also involved conducting analysis using Geometric Phase Analysis for strain determination and extracting the band gap of a Quantum Well using Electron Energy Loss Spectroscopy. 

CDT Involvement:
I was part of the organising committee that helped arranged the 2020 Summer PIADS conclave online as well as presenting my work at both the 2021 and 2022 editions. In 2022, I contributed to the CDT involvement in the Glasgow Science Festival by making a video demonstrating the properties of light passing through water which anyone can do at home. 

Impact Activity:  
I assisted with demonstrating for undergraduate Physics modules at Queen’s from 2020-2022 and involved with helping out with online information sessions for interested undergraduate students looking at joining PIADS/pursing PhD’s. I was also a part of the EPSRC review into Doctoral Training centres which involved a day conference session answering questions about the current state of the centres and what skills are the best to develop alongside other students and academics across other Centres.  

I have presented work at a few conferences around the UK and have had the opportunity to conduct experiments at SuperSTEM, an advanced and dedicated electron microscopy facility, in 2022.  

Contact me:  


I have enjoyed my time within the CDT and have had many opportunities both related to the PhD and outreach. One of my favourites was making a video on the properties of light the Glasgow Science Festival. I would recommend the CDT for the opportunities available that you can you normally may not chance to have with other PhD’s. 

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