AUSTRALIAN researchers are using Molecular Beam Epitaxy, normally used to manufacture semiconductor materials, to build up materials layer by atomic layer, in order to better explore quantum effects.
The Australian National Fabrication Facility Advanced Epitaxy Facility now houses Molecular Beam Epitaxy capabilities, allowing Australian 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.
Dr Stephen Bremner, Senior Lecturer and researcher at UNSW Australia in the School of Photovoltaic and Renewable Energy Engineering, is working to 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,” he explained.
For Dr Bremner, the capabilities of the MBE will allow him to make his own materials, while controlling the nature of matter itself.
MBE is used to manufacture most of the semiconductor lasers used in Blu-ray, DVD and CD players. The same process is used to create Hall Effect devices that are used in hard disc drives to accurately control the drive’s rotational speed, as well as low noise transistors used in satellite receivers.
“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.”
The technique works by directing evaporated beams of atoms or molecules onto a heated semiconductor wafer under ultra-high vacuum conditions.