Scientists at Australian National University have made a discovery which will be central to the development of low-cost biomedical sensors, quantum computing as well as a faster internet. Researcher Tim Burgess added atoms of zinc as impurities to lasers one hundredth the diameter of a human hair and made of gallium arsenide – a material used extensively in smartphones and other electronic devices.
The impurities led to a 100 times improvement in the amount of light from the lasers. “Normally you wouldn’t even bother looking for light from nanocrystals of gallium arsenide – we were initially adding zinc simply to improve the electrical conductivity,” said Burgess, a PhD student in the ANU Research School of Physics and Engineering.
Gallium arsenide is a common material used in photovoltaic cells, lasers and light-emitting diodes (LEDs), but is challenging to work with at the nanoscale as the material requires a surface coating before it will produce light. The new result complements these successes by increasing the amount of light generated inside the nanostructure, said research group leader Professor Chennupati Jagadish, from the ANU Research School of Physics Sciences.
Burgess said that the addition of the impurity to gallium arsenide, a process called doping, did more than just improve the light emission. “The doped gallium arsenide has a very short carrier lifetime of only a few picoseconds, which meant it would be well suited to use in high speed electronics components,” he added.