Stephen Bremner's new equipment

Dr Stephen Bremner talks about his work with latest breakthrough technology and quantum effects

“Imagine you could have any combination of naturally occurring materials in order to make your next breakthrough technology,” says Dr Stephen Bremner, Dr Stephen Bremner, Senior Lecturer and researcher at UNSW Australia. in the School of Photovoltaic and Renewable Energy Engineering. “Well, we can do better than that. We are able to make our own materials using a method that allows us to control the nature of matter itself.”

Most of the semiconductor lasers used in Blu-ray, DVD and CD players are manufactured using a process called Molecular Beam Epitaxy (MBE). Components called Hall Effect devices are used in hard disc drives to accurately control the drive’s rotational speed. Low noise transistors make satellite receivers viable. The list of commercial MBE fabricated technology literally goes on and on. “The industrial demand for devices with higher efficiency, higher frequency and higher sensitivity forces us to look at creating these new devices from scratch – literally by growing them layer-by-layer with each layer being only a few atoms thick,” says Bremner. “This extremely precise level of engineering, which may seem in the realm of science fiction, is very real and is all made possible by understanding and carefully controlling numerous critical things at the atomic level – all at the same time.”

“My research,” says Bremner, “involves exploring novel designs, particularly using quantum effects to tailor properties like light absorption and energy conversion processes in solar cells. One of my ambitions is to create a process to produce commercial quantities of high-performance solar cells using low cost silicon as the base material and ultra-thin layers of carefully chosen but more expensive materials that radically improve the cell’s efficiency. By using such thin layers of the expensive materials the cost of the finished device can be kept low.”

Molecular Beam Epitaxy is technically “a high precision technique used for growing the highest quality compound semiconductor crystals by directing evaporated beams of atoms or molecules onto a heated semiconductor substrate (called a wafer) under ultra-high vacuum conditions.”

The MBE unlocks huge opportunities to UNSW researchers and research students. “A well as being a great research tool, being trained on an MBE opens up the possibility of using other growth technologies and transferring these acquired skills,” says Bremner. “Students develop expertise in solid-state physics, control systems, materials properties, crystal growth and ultra-high vacuum systems. Although this is a very specialised field there is an increasingly growing demand by industry for this particular skill set. There are great job opportunities popping up all over the world.”

My research involves using quantum effects to tailor properties like light absorption and energy conversion processes in solar cells.

Dr Stephen Bremner

One problem with MBE is that these are quite expensive machines to install and setup. The MBE being commissioned is under the auspices of The Australian National Fabrication Facility (ANFF).

According to Scientia Professor Andrew Dzurak, the ANFF director at UNSW, speaking at the unveiling of the ANFF Advanced Expitaxy Facility that houses the MBE: “This new MBE will allow researchers to custom design completely new materials, with properties that cannot be found in nature.”  

The ANFF links eight university-based nodes together and aims to give researchers all across Australia access to state-of-the-art fabrication facilities. “The ANFF is a great idea that works really well and benefits all Australian researchers,” says Bremner. “Through the ANFF we now have a tool that can turn our ideas into working devices. Some people might call it ‘magic’ but it really is science as well as a great example of the power of developing fundamental understanding of matter and its formation. In this case it leads directly to the realisation of technologies that even a short time ago were deemed not possible.”

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