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Diamond Transistors Proposed for use in Spacecraft and Car Engines

October 26, 2018 by Paul Shepard

Diamond is the perfect material to use in transistors that need to withstand cosmic ray bombardment in space or extreme heat within a car engine, in terms of performance and durability. Scientists at Australian National University (ANU) have invented tiny diamond electronic parts that could outperform and be more durable than today's devices in high-radiation environments such as rocket engines, helping to reach the next frontier in space.

The team has developed a new type of ultra-thin transistor, which is a semiconductor widely used to amplify or switch electronic signals and electrical power in devices such as tablets, smart phones and laptops.

Lead researcher Dr Zongyou Yin said the new diamond transistors were promising for applications in spacecraft or car engines.

"Diamond is the perfect material to use in transistors that need to withstand cosmic ray bombardment in space or extreme heat within a car engine, in terms of performance and durability," said Dr Yin from the ANU Research School of Chemistry who has been in the world Highly Cited Researcher list from Clarivate Analytics every year since 2015.

He said such applications were currently dominated by semiconducting compounds-based technology, including Silicon Carbide and Gallium Nitride.

"The Silicon Carbide- and Gallium Nitride-based technologies are limited by their performance in extremely high-power and hot environments, such as in spacecraft or car engines," Dr Yin said.

Schematic structure of diamond:H surface undergoing different ALD processes and their resulting interface electronic properties with diamond:H/MoO3 versus diamond:H/HyMoO3−x transistors. (A) Application of a typical MoO3 ALD process on diamond:H, resulting in surface termination degradation. (B and C) Modified ALD process of MoO3 and HyMoO3−x for preserving diamond:H termination. Right side from top to bottom: Schematic cross-sectional diagram with interface atomistic representations of diamond:H/MoO3 (top) and diamond:H/HyMoO3−x (bottom) FETs and their respective electronic band energy structures with different oxidation state ratios. CB, conduction band; VB, valence band. (click on image to enlarge)

"Diamond, by contrast to Silicon Carbide and Gallium Nitride, is a far superior material to use in transistors for these kinds of purposes.

Dr Yin from the ANU Research School of Chemistry

"Using diamond for these high-energy applications in spacecraft and car engines will be an exciting advancement in the science of these technologies."

Dr Yin said the team's diamond transistor was in the proof-of-concept stage.

"We anticipate that we could have diamond transistor technology ready for large-scale fabrication within three to five years, which would set the base for further commercial market development," he said.

The team purchased special forms of tiny, flat diamonds and modified the surfaces so that they could grow ultra-thin materials on top to make the transistors.

The material that they grew on the diamond consisted of a deposit of hydrogen atoms and layers of hydrogenated molybdenum oxide.

ANU conducted this study in collaboration with the Massachusetts Institute of Technology in the United States and Technion-Israel Institute of Technology in Israel.

The study is published in Science Advances.