While using diamonds is one of the most promising materials for quantum computing systems, too much nitrogen in a diamond disrupts its quantum storage capabilities.
The novel ultra-high-purity diamond contains no more than three parts per billion of nitrogen atoms, as required for quantum applications, such as quantum computers, quantum memory, and quantum sensing devices.
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The diamond wafers, called Kenzan Diamond, could be used for quantum memory as the ultra-high purity of the diamond allows it to store a whopping 25 exabytes, the equivalent of one billion Blu-Ray discs, of data.
Until now, usable diamond crystals were only about four millimeter square. It is expected that this new technology will lead to the realization of quantum computers in the future.
Diamond wafers are manufactured by growing the crystals on a substrate material, usually a flat surface. In diamond crystal growth technology, nitrogen gas has to be used to obtain a high growth rate, so nitrogen impurities with a concentration of several ppm are mixed into the diamond crystal and cannot be used in a quantum computer.
The main problem with this method is that the diamond can crack under the strain, degrading its quality. In the new method, the team uses a substrate surface that is shaped like steps, which spreads the strain horizontally and prevents cracking. This newly used surface allows them to make larger diamond wafers with higher purity.
The research will be presented at the International Conference on Compound Semiconductor Manufacturing Technology in May.
Adamant Namiki plans to commercialize Kenzen Diamonds in 2023, while working on doubling the size of the wafers.