ProfessorRongkun Zheng

Project Opportunities

Title: Novel Properties of Semiconductor Nanostructures by Strain Engineering

Summary of opportunity:

This project aims to understand the novel properties of nanostructured semiconductors under strain by advanced characterisations and simulations.

Opportunity synopsis:

Semiconductor nanostructures show distinct properties from their bulk counterparts under stain. This project aims to understand these novel properties by advanced characterizations and simulations. it is not only of great research importance, but also opened a new window for novel nanodevice designing, taking the advantage of strong coupling between strain and physical properties.

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Project Opportunities

Title: Microscopic Origin of Ferromagnetism in Diluted Magnetic Semiconductors

Summary of opportunity:

This project aims to understand the microscopic origin of ferromagnetism in Diluted Magnetic Semiconductors, and to direct the fabrication of high quality Diluted Magnetic Semiconductors.

Opportunity synopsis:

High quality diluted magnetic semiconductors are required to realize spintronics - the next generation electronics. Although Diluted Magnetic Semiconductors above room temperature have been widely reported, there are strong variations in the reported spintronic behaviours. In particular, the origin of ferromagnetism is not clear. Therefore, there is a major opportunity for the application of new, element- and position-specific analysis techniques for revealing the microscopic origin of ferromagnetism in DM. In this project, we will employ atom probe and other microscopic techniques to study the nanostructural effects in Diluted Magnetic Semiconductors. The aims are to understand the microscopic origin of ferromagnetism in Diluted Magnetic Semiconductors, and to direct the fabrication of high quality Diluted Magnetic Semiconductors.

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Project Opportunities

Title: Graphene: a journey of appreciation and exploration via computational simulations

Summary of opportunity:

This project aims to study several graphene-based nanostructures including nanoribbon, nanodots and nanoantidots and their optical, electrical and magnetic properties by first principles simulations.

Opportunity synopsis:

Graphene, single atomic layer of graphite, exhibits truly spectacular structural, mechanical, electronic, thermal and possibly magnetic properties. Graphene and its derivatives hold promise for a vast range of nanotechnologies, particularly in the emerging field of graphene-based nanoelectronics and nanospintronics. This project aims to study several key graphene-based nanostructures including nanoribbon, nanodots and nanoantidots. Their optical, electrical and magnetic properties will be investigated by the state-of-the-art first principles (no experimental parameters) simulations.

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Project Opportunities

Title: Direct Epitaxy of All Inorganic Halide Perovskites for X-ray Detectors

Summary of opportunity:

This project aims to develop high-performance x-ray detectors based epitaxially grown halide perovskite single crystal fims.

Opportunity synopsis:

X-ray detectors are widely used in medical diagnostics and therapy, safety screen and inspection, and scientific equipment. Halide perovskites are the potential game changer due to their (i) strong X-ray attenuation, (ii) exceptional optoelectronic properties, and (iii) low-cost raw materials and crystal growth. The commercialisation is currently hindered by three challenges: (i) large dark current, (ii) integration with read-out circuitry, and (iii) poor stability. This project aims to solve all the main challenges simultaneously by direct epitaxial growth of allinorganic halide perovskite single crystal films on read-out circuitry. The outcomes from this project could lead to the replacement of existing X-ray detection technologies.

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Project Opportunities

Title: Atomic-scale understanding of the degradation of halide perovskites

Summary of opportunity:

This project aims to understand the atomic scale origin and mechanism of halide perovskite degradation.

Opportunity synopsis:

High-efficiency and low-cost perovskite solar cells have achieved remarkable progress over the last few years, but there is still a lack in understanding of why and how they degrade over time. This project aims to understand the instability of halide perovskites by revealing the changes in microstructure and electronic structure at the atomicscale. The expected outcomes of this project will advance our knowledge of the instability of perovskite solar cells and provide critical guidance for future development and optimisation. This will then help the local and global energy sector transition to sustainable energy and so benefit both the economy and the environment.

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Project Opportunities

Title: In-situ STEM investigation of the photocatalysis for water splitting

Summary of opportunity:

This project aims to provide the breakthrough information that is required to improve the efficiency of water splitting, by directly real-time observing, for the first time, photocatalysis at the nanoscale in a transmission electron microscope.

Opportunity synopsis:

Water splitting by means of photoelectrochemical cells, is regarded as the most economical way to acquire the clean and renewable fuels principally hydrogen. However, long-lasting issues such as low sunlight to hydrogen conversion rate, photocorrosion of the catalysts, inadequate knowledge of the photocatalytic mechanism and expensive noble metal decoration, restrict the development of efficient water splitting system for spontaneous hydrogen/oxygen reaction evolution. This project aims to clarify the fundamentals of these problematic issues via in-situ STEM investigation and the outcome will provide new conception and knowledge to address the long-lasting issues within the community in terms of instability and efficiency.

----------Current Research Projects----------

• Novel Properties of Semiconductor Nanostructures by Strain Engineering
• Atomic-level Insights into Semiconductor Nanowires
• Microscopic Origin of Ferromagnetism in Diluted Magnetic Semiconductors
• Graphene: a journey of appreciation and exploration via computational simulations
• Atomic-scale understanding of the instability of perovskite solar cells
• Novel Properties of Semiconductor Nanostructures by Strain Engineering
• Direct Epitaxy of All Inorganic Halide Perovskites for X-ray Detectors
• In-situ STEM investigation of the photocatalysis for water splitting

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Project Opportunities

Project title:

Stabilising perovskite photovoltaics by (A,B)-site co-doping

Project summary:

This project aims to experimentally identify the optimal (A,B)-site co-doping recipe to achieve highly stable and efficient FAPbI3-based solar cells, leveraging on the team’s recent discovery that (A,B)-site co-doping is effective in stabilising FAPbI3 and solving the instability of perovskite solar cells. Improving the long-term stability of perovskite solar cells is a major hurdle to commercialise perovskite solar cells and to minimise climate change. Expected outcomes are new knowledge on FAPbI3 phase transformation, A-/B-site mixed doping method and recipe, and more stable FAPbI3 and FAPbI3-based solar cells. These advances are expected to deliver substantial benefits to green-energy technologies, the environment, and the economy.

This Scholarship is funded by the Australian Research Council (ARC) and aims to support a PhD candidate undertaking research within the School of Physics, Faculty of Science, at the University of Sydney.