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THE DIAMOND WORLD

THE SCIENTIFIC COMMUNITY LOOKS TO DIAMONDS
AS A MATERIAL WITH MULTIPLE APPLICATIONS

 

It has long been said that genius of the diamond business is its ability to elevate a gemstone with little practical function into an object of supreme value. Consumers were nurtured who did not demand that diamonds possess practical applicability, but desired them for what they were perceived to be and what they symbolized.

To be sure, diamonds have long had practical applications, although typically not the type of diamonds that were being set in jewelry. These functional stones generally were lower cost industrial diamonds, which by taking advantage of the mineral being the hardest natural material known to man are widely used in cutting and drilling machinery.

But electronics, and the ability to synthesize high-quality diamonds to meet its needs are creating a new reality, whereby diamond demand will also be driven by industrial need, and the jewelry sector will need to compete for material.

Unsurprisingly, it is the computer sector that has the highest vested interest. Computer chip producers have long relied on the properties afforded by silicon. But as ever more condensed chips are required, the tried and proven glassy substance is being pushed to its limit.

Silicon is a semiconductor, meaning they it can switch between being an electrical conductor and insulator, making it an essential material in transistors, which are the basic electronic building blocks. But e industry today requires semiconductors with a wider bandgap, which are able to move more power more efficiently. Diamonds are considered is the “ultimate ultrawide-bandgap material,” according to a recent New York Times article.

Band gap is not the diamond’s only advantage. It also has ultra-high thermal conductivity, allowing it to remain cool in under super-charged conditions. It is also an extremely efficient electric-charge carrier, and it has extreme breakdown strength, meaning it can absorb high voltages without its structure crumbling.

Even the diamond semiconductor will have its limits. However, a group of scientists at City University of Hong Kong have discovered a method of stretching those boundaries. Using a technique called strain engineering, they are reducing diamonds to nano-sizes where they can then be physically stretched, opening up the internal bands through which energy can travel. This, the scientists say, increases their conducting power exponentially.

Radioactive batteries, which make use of waste from nuclear reactors, are power sources that theoretically can operate for hundreds of years.

A RADIOACTIVE BATTERY THAT GOES ON AN ON

The electronic industry is not the only business sector to be looking at diamond applications. In 2016, a group of physicists and chemists at the University of Bristol began work on what are now being called radioactive diamond batteries.

It began as a solution to get rid of nuclear waste created in reactors that generate electricity. The result is a carbon-14 diamond betavoltaic battery, powered by the beta decay of nuclear waste.

A betavoltaic cell consists of thin layers of radioactive material between semiconductors. As the radioactive material decays, it emits beta particles that knock electrons loose in the semiconductor. This creates electric current.

Using radioactive methane containing the radioactive isotope Carbon-14, which can be obtained from irradiated reactor graphite blocks, the scientists employed the same chemical vapour deposition (CVD) method used to create laboratory-grown diamonds for the jewelry industry to grow radioactive diamonds.  The synthetic diamonds act both as the radioactive source and as the semiconductors.

The result is a long-duration battery that doesn’t need to be recharged. Since the half-life of nuclear waste is so long, the battery will have no measurable degradation for literally hundreds of years, without having to be replaced or recharged.

The scientists already have a is a working prototype, but the power it provides is still low. Even then, an English company called Arkenlight is working on the commercialization of radioactive diamond batteries for pacemakers and sensors, and hopes to hit the market before the end of 2023.

No word on how safe these radioactive batteries are. Presumably Arkenlight has given that some thought.

REFLECTING HIGH-POWERED LASERS

Another group of scientists, these from Harvard University in the United States, have developed a mirror made of diamond sheeting that can steer high-power laser beams without getting destroyed in the process.

Mirrors have long been used to direct laser beams, which are formed by thin layers of materials with varying optical properties. However, if one of those layers has even a minute defect, the laser may burn through the mirror instead being reflected by it.

To create their diamond mirror, the research team used techniques that had been developed to carve nanoscale structures in quantum optics and communications.It required using an ion beam to etch microscopic golf-tee-shaped structures on the surface of a thin diamond sheet,  achieving 98.9 percent reflectivity.

They tested their diamond mirror with a 10-kW laser developed by the U.S. Navy. Although the beam it produces is strong enough to burn through steel, the mirror emerged from the experiment unscathed.

The scientists believe it will be possible to commercialize the technology in a range of fields, from semiconductor manufacturing to the military and defense industries, to deep space communications.

A diamond mirror developed by a group of scientists from Harvard University can reflect high-power laser beams without becoming damaged.