New Paper: Holistic Determination of Optoelectronic Properties using High-Throughput Spectroscopy of Surface-Guided CsPbBr3 Nanowires

Optoelectronic materials form the building blocks of crucial components of modern technology, including solar cells, CCDs, lasers and LEDs. The past decade has seen significant developments in materials science that enable the shrinking of these materials to the nano-scale. These advancements have also created entirely new technologies based around light manipulation. We can now create nano-scale light sources, nano-scale light detectors and nano-scale optics: so we can build a chip that performs processes using light instead of electrical signals.

An important component of these devices are nanowires: these can act as on-chip light sources and tiny optical fibers, essentially the power and wiring of a light based circuit. As materials are shrunk towards the nano-scale, their performance is affected strongly by their size, providing a handle to tune performance of these nanowires  to suit the application. However, herein lies one of the major challenges of this technology; it remains difficult to accurately and repeatedly control the size of these nano-materials when they are made leading to  an unwanted spread in their performance.

High-throughput experiments to study inhomogeneity

Stephen Church of the OMS Lab worked with colleagues in the Joselevich group at the Weizmann Institute in Israel to developed a methodology to optimize these nano-materials by harnessing the inherent variation using big data approaches. He has developed an automated microscope that can study the properties of more than 10,000 individual nano-wires with a suite of different optical experiments. This approach produces a vast dataset that, when considered together, describes the nano-material and can therefore be used to establish the best way to optimize their performance. Crucially, this approach requires very little prior knowledge of the sample and can be applied generally to new nano-materials.

Soft nanowires and the impact of strain

In their recent paper, we demonstrate this approach on wires made of halide perovskites, an emerging material touted for its superior light emission and detection. The material is also “soft”, deforming to fit on its substrate; this causes further spread in properties as the thickness of the wire changes. The big data approach shows the impact of this deformation on the color and the efficiency of light emission from the nano-wires, and shows how the degree of deformation varies across the population.

Open data

This publication is made up of more than just a journal report. The raw data has been made available via FigShare, and the analysis code via github. It is possible to explore and manipulate the raw data using the Google Colab platform.

Reference: Holistic Determination of Optoelectronic Properties using High-Throughput Spectroscopy of Surface-Guided CsPbBr3 Nanowires, Stephen A. Church, Hoyeon Choi, Nawal Al-Amairi, Ruqaiya Al-Abri, Ella Sanders, Eitan Oksenberg, Ernesto Joselevich and Patrick W. Parkinson, ACS Nano (2022) DOI: 10.1021/acsnano.2c01086

Nanowire Week 2022: Talks and Posters

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Nanowire week 2022

Group members Dr Stephen Church and Nikesh Patel have presented their work at the 2022 Nanowire Week meeting in Chamonix, France.

Stephen gave an oral presentation on his recent research on “Nanowire facet reflectivity and lasing performance using high-throughput interferometry“.

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Nikesh presented a poster on his work on “High Intra- and Interwire Uniformity in 2D Radial GaAsP/GaAs Core/Shell Triple Quantum Well Structures

Learning Through Research Internship 2022: Big-Data From High-Throughput Experimentation

The group will again offer an 8-week paid summer internship to work on developing a cloud-based solution for high-throughput data management. This position is only available to current University of Manchester students in their penultimate year of study.

The role will sit alongside PhD and postdoctoral staff in the group, to work on an existing basic method to store and query experimental data produced in the lab. It requires a familiarity with experimental data, the concept of metadata, and python programming.

Further details and the application form can be found at https://careerconnect.manchester.ac.uk/leap/jobSearch.html?id=25265&service=Careers+Service

Details about the scheme are available at https://www.manchester.ac.uk/study/undergraduate/teaching-learning/methods-materials/research/.

MRS Fall 2021 – Mobility, Quantum Efficiency and Defect Density from High Throughput Spectroscopy of CsPbBr3 Nanowires

Stephen Church will present a talk on his recent work on holistic modelling using high-throughput spectroscopy virtually at MRS Fall 2021. This work, in collaboration with Prof Ernesto Joselevich at the Weizmann Institute uses high-throughput multimodal techniques to simultaneously model mobility, quantum efficiency and defect density from a single correlative study.

New Paper: Defect-Free Axially Stacked GaAs/GaAsP Nanowire Quantum Dots with Strong Carrier Confinement

Transmission electron microscopy and room-temperature photoluminescence of a dot-in-wire structure.

In a new collaboration between Yunyan Zhang and Profs. Huiyun Liu (UCL), Ana Sanchez (Warwick) and David Mowbray (Sheffield) we report the fabrication and measurement of a GaAs/GaAsP quantum dot-in-wire structure in Nano Letters.

While many material architechtures have been explored for single photon emission, the GaAsP-GaAs system provides strong carrier confinement and sharp interfaces, and can be grown directly onto a silicon substrate. This is a new route to silicon integrated single photon devices.

Reference: Defect-Free Axially Stacked GaAs/GaAsP Nanowire Quantum Dots with Strong Carrier Confinement, Yunyan Zhang, Anton V. Velichko, H. Aruni Fonseka, Patrick Parkinson, James A. Gott, George Davis, Martin Aagesen, Ana M. Sanchez, David Mowbray, and Huiyun Liu, Nano Lett. (2021), DOI: 10.1021/acs.nanolett.1c01461

Learning through Research Internship available

A student experience intership is available in the group for a period of 8 weeks over summer 2021. This paid position is available to any Manchester undergraduate student who is not currently in their final year. They are designed to provide experience of academic research to undergraduates who are considering this as a career choice, and will involve a real research project working alongside PhD and postdoctoral level researchers.

This project “Making Nanomaterial Data Public: An Open-Source Toolbox” will build on our new nanomaterials database to explore how to best make this data open-source, to be used for materials research or data-science applications. It would suit students interested in data science and nanotechnology and with some ability in python/jupyter.

For more information including an application pack, see https://careerconnect.manchester.ac.uk/leap/jobSearch.html?id=1715&service=Careers+Service