A team of scientists from Nagoya City University (NCU) in Japan has developed an energy-efficient strategy to enrich silicon surfaces with a dilute deuterium solution.
Deuterium is a heavier but less abundant version of the hydrogen atom that offers many practical benefits, including for semiconductors.
The surface of silicon-based semiconductors has to be ‘passivated’ with hydrogen to ensure silicon atoms don’t detach easily (desorption), thereby increasing the durability of microchips, batteries and solar cells. It has been established that passivation with deuterium results in about one hundred times lower desorption than with hydrogen, making deuterium a potentially indispensable ingredient in electronic devices.
Unfortunately, both the procurement of deuterium and available techniques to enrich silicon surfaces with it are very energy inefficient and require very expensive deuterium gas. Until now that the NCU researchers found that an exchange reaction from hydrogen to deuterium can occur on the surface of nanocrystalline silicon (n-Si). The exchange process is closely related to differences in the surface vibrational modes between hydrogen- and deuterium-terminated n-Si. Exploiting the quantum effects on the surface of n-Si could pave the way to new methods to procure and utilise deuterium.
“The efficient hydrogen-to-deuterium exchange reaction we reported may lead to sustainable, economically-feasible and environment-friendly deuterium enrichment protocols, leading to more durable semiconductor technology,” said Professor Takahiro Matsumoto at NCU who led this project’s team. “Let us hope the findings of this work allow us to benefit more from the heavier isotopes of hydrogen without taking a toll on our planet.”