Although diamonds are widely believed to be hard and unstable, thin films have been found to show elastic deformation – and this new construction can have a profound effect on a variety of applications.
A team of researchers from the City University of Hong Kong (CityU) has successfully demonstrated the large-scale uniform tensile elastic tension for diamonds. Using a nanomecanical approach, researchers fabricated it over microfabricated diamond arrays, demonstrating the potential of these rigid diamond films for potential applications in microelectronics, photonics, and quantum information technologies.
Dr. Lu Yang, Associate Professor from CityU’s Department of Mechanical Engineering, with members of the collaborative study including researchers from the Massachusetts Institute of Technology (MIT) from the U.S. and the Harbin Institute of Technology (HIT) in China. The results of their research are published in the journal Science on January 1, 2021.
“This is the first time that diamonds have shown great elasticity of wear with tensile tests,” Dr. Lu said in a CityU press release.
(Photo: Photo by Tim Boyle / Journalists)
370125 02: The 620-carat Sefadu Diamond is on display May 24, 2000, at the Ross-Simons jewelery store in Northbrook, IL. The giant Sefadu was discovered in 1970 near the city of Sefadu in the West African country of Sierra Leone and is today the largest rough diamond, the seventh largest rough diamond ever found.
New demand for diamonds
Diamonds in an industrial setting are best known for their hardness, finding wide applications in cutting, drilling or grinding requirements. However, recent advances have also revealed the precious ore as a high-performance electronic and photonic material, thanks to its electric mobility, ultra-high thermal conductivity, high breaking strength, and wide bandgap properties.
However, its natural features – a large bandgap and a tight crystalline structure – also make the whipping process virtually impossible. Doping, or the process of incorporating materials into a substrate to control or modify its electrical properties, is required to make it a viable electronic and optoelectronic device. One way to work around this limitation is through a technique known as “strain engineering,” where a large external force is applied to change the structure of the diamond band and, with it, its properties – action. which was previously considered “impossible” for those who were very hard diamonds.
RELATED ARTICLE: Ashes to Diamonds – The Science behind making Synthetic Diamonds
In 2018, Dr. Lu’s team discovered that it is possible to bend nanoscale diamonds, even though they have very large strain forces – unlocking the potential of strain engineering on the material. To achieve this, researchers sampled single-crystal diamond samples from solid single crystals. This resulted in bridge-like structures about one micrometer long by 300 nanometers wide, with slightly wider heads for grip. Their samples then undergo repetitions of continuous and controlled loading tensile tests, revealing uniform deformation across the entire region rather than local deformation.
Tunable bandgap for diamond strips
After the sample geometry achieved using American Society for Testing and Materials (ASTM) standard, researchers were able to reach uniform tensile strains of up to 9.7 percent, surpassing the 7.5 percent previously from their 2018 test. He recorded the bandgap reduction rate down from 5 electronvolts to 3 electronvolts, based on the researchers’ spectroscopic analysis.
With their nanomechanical approach, researchers were able to open strain engineering as an opportunity for microfabricated diamonds. It showed measurable property change in diamond bond structure.
“I believe we have a new era for diamonds ahead of us,” said Dr. Lu.
RELATED ARTICLE: Q&A by Aerospace Engineer turned into a diamond scientist
Check out more news and information about Diamonds on Science Times.