Diamonds are no longer just for jewelry

Diamonds are no longer just for jewelry

Photoconductive switch made of synthetic diamond that precipitates by chemical evaporation. Credits: Lawrence Livermore National Laboratory

As for the semiconductor industry, silicon has ruled like a king in the field of electronics, but it is coming to an end with its physical limits.

To power the grid, locomotives, and even electric cars more efficiently, scientists at Lawrence Livermore National Laboratory (LLNL) are turning to diamond as a semiconductor with a wide bandwidth.

Diamond has been shown to have superior carrier mobility, break the electric field and thermal conductivity, the most important properties for powering electronic devices. This has become particularly desirable following the development of a chemical precipitation process (CVD) for the growth of high quality single crystals.

The team investigated the properties of such synthetically made diamonds that are of better quality than natural ones. “In electronics, you want to start with the cleanest possible material so that you can shape it into a device with the desired properties,” said LLNL physicist Paulius Grivickas, the lead author of the paper that appeared. Letters of applied physics.

In photoconductive devices, the best combination of conductivity and frequency response is achieved by introducing impurities that control the life of the carrier recombination. The researchers found that diamond is a cheap and easy alternative to this approach by electron radiation, which results in recombination defects by ejecting lattice atoms.

“We said to ourselves‘ let’s take this high quality CVD diamond and radiate it to see if we can adjust the lifespan of the wearer, ”Grivackas said. “We finally figured out which radiation defect is responsible for the life of the carrier and how the defect behaves under annealing at technologically relevant temperatures.”

Photoconductive diamond switches produced in this way can be used, for example, in an electrical network to control electric and voltage shocks, which can burn equipment. Current silicon switches are large and bulky, but those based on diamonds can achieve the same with a device that could fit on the tip of a finger, Grivickas said.

The research also has applications in energy delivery systems where the team has demonstrated the possibility of generating a megawatt-class radio frequency, which requires optimizing the high-frequency diamond response.

Preparation of a single crystal diamond for electronics

More information:
P. Grivickas et al. Recombination and diffusion of high purity diamond carriers after electron radiation and annealing, Letters of applied physics (2020). DOI: 10.1063 / 5.0028363

Provided by Lawrence Livermore National Laboratory

Citation: Diamonds are no longer just for jewelry (2020, December 22) downloaded on December 23, 2020 from

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