Diamonds on Demand

Sitting in the reclining chair during my last visit to dentist, I stared very intently at the drill that the dentist was about to use in my mouth. I started tensing up as I anticipated the high pitched shrill sound that would accompany the grinding of the dental drill against my teeth. I remembered that those drills could be made out steel with a tungsten carbide coat, or even worse, a diamonds coating. The possibility that the hardest naturally occurring substance on Earth causing that high pitched shrill unnerved me even more. I had to breathe and relax. Diamonds after all are also a girl's best friend, right? So that does not make them all bad. And, as I would later find out, diamonds could be scientist's best friend as well, and they can now come from the ground or a machine.

Diamonds were first widely synthesized by General Electric in 1955. The GE method used machines to turn carbon ash into diamonds by mimicking the high pressure, high temperature (HPHT) environment found deep under the earth's surface where diamonds naturally form. The first man-made diamonds were no larger than a grain of sand and were more useful in commercial and industrial applications such as dental drills or blade sharpeners. Over the next 50 years, much effort was poured into improving the HPHT process. During the ensuing time, companies such as Sumitomo Electric, and even the largest diamonds mining company, De Beers, have reported making industrial grade diamonds. However in 2001, Gemesis, a Sarasota, Florida company announced that it had acquired and refined the HPHT technology enough to start making large, high quality diamonds for use in jewelry.

While improvements were being made to the HPHT method, another possible strategy for diamonds synthesis was being investigated. Chemical vapor deposition (CVD) is a low pressure method by which carbon would be turned into plasma, allowed to drift into a deposition chamber, and collect onto a substrate or seed diamonds. A slow, tedious method of CVD process was first done by William G. Eversole of Union Carbide in 1952. Union Carbide, however, ended up giving up the project soon afterwards. Subsequently in the 1960's a small team of American and Russian scientists improved CVD diamonds growth, making it easier to do. The process was ultimately refined to commercial viability by Japanese scientists in the 1980's. However, all the diamonds that had been synthesized up till then was made up of microscopic diamonds crystals that aggregated together to form a larger chunk.

Working in his garage, former Bell Labs scientist Bryant Linares used his expertise in crystal growth technology to build machines that could make diamonds via CVD. Linares inadvertently left a diamonds piece in a beaker of acid over the weekend and when he examined it afterwards, he came to a realization.

"When I came in Monday, I couldn't see the [stone] in the beaker. The diamonds was colorless and pure. That's when I realized we could do gemstones," Linares told USA Today.

Linares established Apollo Diamonds in 1990 to commercialize the diamonds he was making in his garage. The company refined Linares technology to the point that it could grow high quality single crystal, multiple carat diamonds in its machines in just a few days. In 2006, they started selling their diamonds to the public.

The "Cultured Diamonds"

There is a lot at stake for Gemesis and Apollo on entering the jewelry diamonds market. According to USA Today, if either company can capture at least 1% of the $60 billion dollar market, the company will have an in flux of $600 million in revenue. Considering the low costs the companies incur in making a diamonds, they would stand to profit handsomely.

However, major hurdles stand in the way of market acceptance of Gemesis and Apollo's wares. De Beers, as part of its "Gem Defense Program," has developed sophisticated instruments for gem laboratories - such as those at the Gemological Institute of America and the Diamonds High Council - in order to differentiate between synthetics and mined diamonds. The machines dubbed DiamondsSure and DiamondsView had been in the works since 2000 and improved versions of the machines were sent out in 2002.

Man-made diamonds producers remain unflustered; these companies have pushed the term "cultured diamonds" as way to market their products to consumers and wholesale buyers alike. The use of "cultured" tries to capture the previous success of the cultured pearl industry had with the word.

Industry groups led by the Jewelers Vigilance Committee have lobbied the Federal Trade Commission (FTC) to force companies like Gemesis and Apollo to label their diamonds as "synthetic." In 2001, the FTC ruled that labeling man-made diamonds as "diamonds" was "unfair and deceptive," but have not commented about the use of "cultured."

Slowly, as these companies expand their distribution, they have pledged to be completely transparent about the product they are selling. To that end, Gemesis and Apollo have laser inscribed a small indicator on all their diamonds to aid in identification of these stones.

Despite the high-tech instrumentation and marketing, the ultimate test is whether consumers will buy diamonds grown in a machine. After all, part of the allure of diamonds is their supposed rarity and high price.

In the September 2003 issue of Wired magazine, Diamonds High Council (the chief Belgian diamonds industry representative) senior scientist Jef Van Royen predicted the answer to the consumer approval question will be "No". "If people really love each other, then they give each other the real stone. It is not a symbol of eternal love if it is something that was created last week," Van Royen said.

De Beers spokeswoman Lynette Gould echoed that sentiment in the Wall Street Journal earlier this year, "De Beers is confident that synthetics will not have the same emotional and financial value as diamonds because the value of diamonds is inextricably linked to how they were naturally formed billions of years ago."

However Gemesis founder Carter Clark told Wired a very different opinion. "If you give a woman a choice between a 2-carat stone and a 1-carat stone and everything else is the same, including the price, what's she gonna choose?" he asks. "Does she care if it's synthetic or not? Is anybody at a party going to walk up to her and ask, 'Is that synthetic?' There's no way in hell."

Linares also responded similarly. "Diamonds considered worthy of jewelry can only come from the ground'. That conventional thinking has been around for as long as people can remember.. Apollo Diamonds is challenging conventional wisdom. That is going to take some longer than others to accept," Linares wrote by e-mail.

According to the Wall Street Journal, only 400,000 carats of diamonds were made while 130 million carats of diamonds were mined last year. Thus man-made diamonds producers still have a long way to go before they become a real challenger to De Beers and company.

Diamonds Can Do More

Despite their disagreement over man-made diamonds as gems, De Beers, Gemesis, and Apollo are still in agreement of one thing: the advent of large, high quality synthetic diamonds will be a boon for technological applications, particularly for advancing sensor, semiconductor, and other electronics applications.

"Diamonds has so many superior properties compared to other materials, that it enables very advanced applications beyond gemstones," wrote Linares by e-mail.

In the scientific literature there is more than 70 years worth of research into various electronic applications. Diamonds has been investigated in possible applications in sensors for radiation, chemical, and biological presence. Diamonds has also been researched for use as a very small mechanical cantilever that can be fabricated with an integrated circuit; this combination of small mechanical devices and integrated circuitry is called a microelectromechanical system (MEMS). As transistors turned computers from giant, room-filling machines into handheld devices, MEMS can shrink mechanical devices and tie them to circuits so that they can respond to electrical signals.

There has also been great excitement over the use of diamonds as a semiconductor. A semiconductor is a material able to conduct electricity after application of a small but substantial input of current and voltage. To aid in the conduction process, a charged particle is usually added to the main semiconductor in a processing called "doping". Normally an insulator, diamonds doped with elements like boron enable it to behave as an insulator. ¬¬Diamonds are of particular interest because it one of the highest known thermal conductivities of any material at any temperature. As such, there is less concern a device (such as computer chip) made out of diamonds will fail while operating high temperatures (T > 390 F).

This high thermal conductivity also lends itself to use as lenses in high powered lasers. "Thermal management is a major challenge to increasing a laser's power," explains Textron scientist Yulin Wang to USA Today. A laser manufacturer, Textron uses high purity and quality diamonds made by Apollo to handle the high temperatures that arise during laser operation.

Also companies such as Lucent are looking into diamonds as holographic storage devices that will use lasers to store information as 3D patterns within the crystal. This kind of holographic storage can potentially store up to 10,000 movies

However all these applications have had to remain in the laboratory as diamonds were very expensive, of too low quality for electronics use, or a combination of the two.

The current challenge for these companies is to grow them into wafers of useful size at relatively low cost. So far the largest wafers are no bigger than a few centimeters square, and as such there is still much work to do in order to make them larger.

In the industrial arena, Apollo and Gemesis are joined by Element Six (formally De Beers Industrial Diamonds) as well as other larger industrial, academic, and government research programs interested in the untapped potential of cheap diamonds synthesis.

As large, high quality synthetic diamonds have only recently been produced, time will tell if the diamonds research community will be able to solve the daunting technical challenges that still lie before them.

Now whether people may be prized for their beauty or their other amazing properties, the ability replicate some of nature's finest handiwork has opened doors that people could only dream about in the past. It is time to set out and see what will come of this maturing technology.

References

[1] Davis, J. "The New Diamond Age." Wired (Sept. 2003) [2] Maney, K. "Man-made Diamonds Sparkle with Potential", USA Today. (6 October 2005). [3] O'Connell, V. "Gem War" Wall Street Journal. (13 Jan. 2007) [4] Yarnell, A. "The Many Facets of Man-Mad Diamond" Chemical and Engineering News. (2 Feb. 2004).
JYI publishes undergraduate research from the natural sciences, mathematics, engineering, and from some of the social sciences, such as psychology and the history of science.
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