Researchers find way to produce very large diamonds very fast
May 16, 2005
Washington, D.C. Researchers at the Carnegie Institution's Geophysical Laboratory have learned to produce 10-carat, half-inch thick single-crystal diamonds at rapid growth rates (100 micrometers per hour) using a chemical vapor deposition (CVD) process. This size is approximately five times that of commercially available diamonds produced by the standard high-pressure/high-temperature (HPHT) method and other CVD techniques. In addition, the team has made colorless single-crystal diamonds, transparent from the ultraviolet to infrared wavelengths with their CVD process.
Figure 1. The variety of single crystal diamonds produced by the Carnegie high-growth rate CVD process.
"High-quality crystals over 3 carats are very difficult to produce using the conventional approach," commented Dr. Russell Hemley who leads the diamond effort at Carnegie. "Several groups have begun to grow diamond single crystals by CVD, but large, colorless, and flawless ones remain a challenge. Our fabrication of 10-carat, half-inch, CVD diamonds is a major breakthrough." The results were reported at the 10th International Conference on New Diamond Science and Technology, Tsukuba, Japan, on May 12, and will be reported at the Applied Diamond Congress in Argonne, Illinois, May 18.
Most HPHT synthetic diamond is yellow and most CVD diamond is brown, limiting their optical applications. Colorless diamonds are costly to produce and so far those reported are small. This situation limits general applications of these diamonds as gems, in optics, and in scientific research. Last year, the Carnegie researchers found that HPHT annealing enhances not only the optical properties of some CVD diamond, but also the hardness [1]. Using new techniques, the Carnegie scientists have now produced transparent diamond using a CVD method without HPHT annealing (Fig. 1).

Figure 2. Single-crystal diamond block formed by deposition on 6 {100} faces of a substrate diamond, such as the 4 x 4 x 1.5 mm3 crystal shown below.
To further increase the size of the crystals, the Carnegie researchers grew gem-quality diamonds sequentially on the 6 faces of a substrate diamond plate with the CVD process (Fig. 2). By this method, three-dimensional growth of colorless single-crystal diamond in the inch-range (~300 carat) is achievable.

Figure 3. 12 mm (1/2 inch) 5 carat diamond laser cut from a 10 carat single crystal produced by high-growth rate CVD. The diamond was laser cut (and inscribed) from a diamond block and only partially polished.
Finally, new shapes have been fabricated with the blocks of the CVD single crystals. Figure 3 shows a 12-millimeter anvil that can be used for new types of scientific experiments.The standard growth rate is 100 micrometers per hour for the Carnegie process, but growth rates in excess of 300 micrometers per hour have been reached, and 1 millimeter per hour may be possible. With the colorless diamond produced at ever higher growth rate and low cost, large blocks of diamond should be available for a variety of applications. "The diamond age is upon us," concluded Hemley.
Source: Carnegie Institution
-
Bit of bling adds new dimension to laser beam technology
Dec 11, 2008 |
4.2 / 5 (21) |
11
-
New Process Promises Bigger, Better Diamond Crystals
Oct 27, 2008 |
4.7 / 5 (35) |
3
-
Diamonds key to a sparkling listening experience
Feb 18, 2005 |
4 / 5 (1) |
0
-
Nanodiamond coatings safe for implants: study
Feb 05, 2012 |
5 / 5 (8) |
5
-
New research explains how diamond rich kimberlite makes its way to Earth's surface
Jan 19, 2012 |
4.7 / 5 (6) |
9
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (31) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (3) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (1) |
0
More news stories
Employers feel no love for unscrupulous practice of 'service sweethearting'
A new study led by two Florida State University marketing professors finds that some frontline service employees who are rewarded for hikes in customer loyalty and satisfaction also may engage in "service ...
Other Sciences / Economics & Business
8 hours ago |
4 / 5 (1) |
4
A frank discussion of the power law and linking correlation to causation
(PhysOrg.com) -- Michael Stumpf a mathematics professor at Imperial College in London, and Mason Porter a lecturer at Oxford have teamed together to write and publish a perspective piece in Science regarding the in ...
The question of life in the ancient world
Theres a general feeling that we dont get the Greeks ancient or modern. Many, including heads of state like Angela Merkel, visibly shake their head in exasperation, rightly or wrongly, at ...
Other Sciences / Archaeology & Fossils
13 hours ago |
1.3 / 5 (3) |
4
Sonic Cradle lands spot in TED exhibition
A Simon Fraser University graduate student project that melds music, meditation and modern technology has landed a rare spot as an exhibit at TEDActive 2012 in Palm Springs, California this month.
10 hours ago |
not rated yet |
0
Chilean miners' rescue capsule on show in London
The capsule used to rescue Chilean miners trapped underground for two months goes on display Saturday at the Science Museum in London -- the first time it has been seen in Europe.
12 hours ago |
not rated yet |
0
Google users warned of threat to smartphone wallets
Users of Google smartphone wallets were being warned on Friday that there is a way to crack pass codes intended to thwart thieves from going on illicit shopping sprees.
Anonymous knocks CIA website offline (Update)
The website of the Central Intelligence Agency was inaccessible on Friday after the hacker group Anonymous claimed to have knocked it offline.
Complex wiring of the nervous system may rely on a just a handful of genes and proteins
Researchers at the Salk Institute have discovered a startling feature of early brain development that helps to explain how complex neuron wiring patterns are programmed using just a handful of critical genes. ...
New error-correcting codes guarantee the fastest possible rate of data transmission
Error-correcting codes are one of the triumphs of the digital age. Theyre a way of encoding information so that it can be transmitted across a communication channel such as an optical fiber o ...
The power of estrogen -- male snakes attract other males
A new study has shown that boosting the estrogen levels of male garter snakes causes them to secrete the same pheromones that females use to attract suitors, and turned the males into just about the sexiest ...
Humans may have helped the decline of African rainforests 3000 years ago
(PhysOrg.com) -- Large areas of rainforests in Central Africa mysteriously disappeared over three thousand years ago, to be replaced by savannas. The prevailing theory has been that the cause was a change ...