Engineering

A novel laser slicing technique for diamond semiconductors

Silicon-based materials are currently the undisputed leaders in the field of semiconductors. Even so, scientists around the world are actively trying to find superior alternatives for next-generation electronics and high-power ...

Electronics & Semiconductors

Team devises crystal-clear solution to quantum computing puzzle

University of Texas at Dallas researchers have developed a new approach that addresses challenges in the field of quantum computing and has the potential to revolutionize computing, communications and electronic security.

Energy & Green Tech

New energy-saving super magnet gets first test run

Testing has begun at Diamond Light Source for an energy-saving super-magnet, designed and built by the Science and Technology Facilities Council (STFC), for our next generation of particle accelerator.

Electronics & Semiconductors

Development of a diamond transistor with high hole mobility

Using a new fabrication technique, NIMS has developed a diamond field-effect transistor (FET) with high hole mobility, which allows reduced conduction loss and higher operational speed. This new FET also exhibits normally ...

Diamond

In mineralogy, diamond (from the ancient Greek αδάμας – adámas "unbreakable") is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools.

Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors), which results in its characteristic luster. Excellent optical and mechanical properties, combined with efficient marketing, make diamond the most popular gemstone.

Most natural diamonds are formed at high-pressure high-temperature conditions existing at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a high-pressure high-temperature process which approximately simulates the conditions in the Earth mantle. An alternative, and completely different growth technique is chemical vapor deposition (CVD). Several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have been developed to distinguish natural and synthetic diamonds and diamond simulants.

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