GaAs: not as stable as thought?
Cardiff team see small pockets of metastability in GaAs atomic structure during MBE growth
Scientists from Cardiff University have spotted previously unseen 'instabilities' in GaAs. By using a low energy electron microscope combined with an MBE machine, they were able to observe dynamic changes on the atomic structure of the material during fabrication.
Their findings, published in Physical Review Letters, identified small pockets of instability that appeared and then disappeared.
The team at Cardiff University’s School of Physics and Astronomy and the Institute for Compound Semiconductors say this is the first time that this phenomenon, dubbed 'metastability', has been observed on GaAs surfaces.
Co-author of study Juan Pereiro Viterbo, from Cardiff University’s School of Physics and Astronomy, said: “At the moment we do not know whether this phenomenon is affecting the growth of semiconductor device structures – this is what we need to study next.
“If this phenomenon were to occur during the growth of semiconductor devices then this could have profound consequences.
“Ultimately these findings are helping us to better understand what is happening at the molecular scale, which will enable us to develop new materials and structures, reduce defects in existing compound semiconductor devices and therefore develop better electronics for our communication systems, computers, phones, cars and more.”
“Even though GaAs have been well studied, the use of low energy electron microscopy in the growing process allows us to observe dynamic events that have never been seen before,” concluded Viterbo.
'Surface Phase Metastability during Langmuir Evaporation' by K. Hannikainen et al; Phys. Rev. Lett. 123, 186102 – Published 1 November 2019
