Improving the properties of silicon by replacing hydrogen with deuterium on the surface layer

In a rare collaboration, two scientists, brothers working in independent disciplines, combined complementary expertise to tackle a chemical problem related to the use of silicon in electronic devices.

The head of the National Deuteration Center, Dr Tamim Darwish, suggested to his brother, Dr Nadim Darwish, a senior lecturer in molecular electronics at Curtin University, that deuterating silicon could improve its properties.

Dr Tamim Darwish is very familiar with the unique properties of deuterium, an isotope of hydrogen used to replace hydrogen in molecules and on which the work of the National Deuteration Facility (NDF) is focused.

This ANSTO facility is a world leader in deuteration for research applications and specializes in providing tailor-made deuterated molecules and labeling techniques.

The results of their research published in ACS Applied Materials and Interfaces reported improvements in silicon properties when hydrogen was replaced by deuterium on the surface layer.

In recent years, technology combining silicon and organic molecules has attracted considerable interest for various applications such as sensors, solar cells, power generation and molecular electronic devices.

The challenge with this technology is that the silicon and hydrogen surfaces (Si−H surfaces), essential to the construction of these devices, are prone to oxidation. This oxidation can harm the stability of devices both mechanically and electronically.

In this study, the Darwish brothers and their colleagues discovered that if hydrogen is replaced with deuterium, thereby creating Si−D surfaces, these surfaces become much more resistant to oxidation when exposed to positive voltages or negative. Si−D surfaces demonstrated more stability against oxidation and their electrical characteristics were more consistent compared to Si−H surfaces.

The investigators recommended using Si−D surfaces instead of Si−H surfaces in applications requiring non-oxidized silicon surfaces, such as electrochemical biosensors, silicon-based molecular electronic devices, and silicon-based triboelectric generators. of silicon.

The significant surface isotope effects reported in this study have implications for the design of silicon-based devices, molecular electronics, and silicon-based power generation devices. Furthermore, these results have an impact on the interpretation of the charge transport characteristics in such devices.