Diamond-Based Semiconductor Shows Highest Breakdown Voltage; Could It Be the Solution to Reach Carbon Neutrality?

To reach carbon neutrality by 2050, a fundamental change in electronic materials is needed to create a more resilient and reliable electricity grid. According to new research, diamonds might answer critical issues in the transition to renewable energy.

Potential of Diamond in Electronic

According to the US Energy Information Administration, the global electricity demand will increase by almost 50% by 2050. In the US, two-thirds of the generated electricity gets lost and does not reach the consumers.

Scientists suggest switching from alternating current to direct current to boost power-grid efficiency. A DC grid would eliminate the need for rectifiers and reduce the use of transformers that lower voltage for distribution. The resultant DC power grid is believed to reduce the current AC grid losses by 90%.

Supporting this type of grid requires power electronics, which can help control and channel the flow of electricity. It is estimated that 50% of the world's electricity is currently controlled by power devices and is assumed to increase to 80%. A DC grid with high voltages and currents calls for power electronics that are faster and stronger than current silicon devices.

Diamond is considered to be the hardest semiconductor known. It also has a high breakdown voltage, which enables it to support a high voltage before becoming electrically conductive. These properties mean diamond semiconductor devices can operate at higher currents and voltages with less material than conventional electronics.

Next-Generation Semiconductors

At the University of Illinois Urbana-Champaign, a group of researchers have developed a semiconductor device made of diamond. Compared to previously designed diamond devices, this new material has the highest breakdown voltage and the lowest leakage current. The result of their study is discussed in the paper "Diamond p-Type Lateral Schottky Barrier Diodes With High Breakdown Voltage (4612 V at 0.01 mA/Mm)".

Led by electrical and computer engineering associate Professor Can Bayram, researchers scale up breakdown voltages by adjusting the horizontal distance between the electrodes without using a thick drift layer. By doing so, they achieved record-high breakdown voltages of 5,000 volts with drift layers as thin as a few microns. In theory, the device is expected to sustain up to 9,000 volts, the highest voltage reported for a diamond device.

Aside from having the highest breakdown voltage, the device also shows the lowest leakage current, comparable to a leaking faucet but with energy. Leakage current is another factor to be considered when boosting power-grid efficiency, as it affects the overall efficiency and reliability of the device.

The team plans to build their device on an ultra-wide bandgap material, synthetic diamond. They also aim to continue optimizing their material to reach the performance limits of diamond's potential. They believe that in the future, diamonds will enter the semiconductor market at high-end power levels. Diamond-based converters will be cost-competitive, considering the reduction of the semiconductor size and the simplification of the system.

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