Diamond-based semiconductors for a faster, more resilient power grid

The University of Illinois has been selected to receive $3.5 million in funding from the U.S. Department of Energy Advanced Research Projects Agency-Energy (ARPA-E). This funding is part of ARPA-E’s ULTRAFAST program, which aims to improve control and protection of the domestic power grid through chip-focused innovations.

Power disruptions cost the U.S. over $150 billion every year, and the electric grid faces challenges from aging infrastructure to a growing number of severe weather events. The ULTRAFAST program plans to innovate power electronics technology to enable a secure, reliable grid that can meet higher demands for electricity. The U.S. aims to become carbon neutral by 2050, so it’s vital to increase the electricity grid capacity and integrate more renewable energy sources.

Grainger Engineers are rising to this challenge as project leaders and co-PIs in three of the ULTRAFAST projects recently funded by ARPA-E. 

ECE associate professor Can Bayram leads a $3 million dollar project headed by the University of Illinois and is co-PI on another project led by Great Lakes Crystal Technologies to develop optically-triggered diamond semiconductor switching devices. ECE associate professor Shaloo Rakheja is co-PI on a project led by Lawrence Livermore National Laboratory, partnering with the University of Illinois, Stanford and UC-Berkeley to build a high-power diamond optoelectronic device.

All projects focus on diamond as a novel material for semiconductor devices. This may seem like an expensive choice, but as Bayram explains, “Diamond is carbon, so the underlying element is not expensive, and lab-grown diamonds make it much more affordable.”  

Compared to conventional semiconductor materials such as silicon, diamond has many advantages. “Diamond is an ultrawide bandgap material that has very high breakdown strength, better carrier mobility, and high thermal conductivity,” Rakheja comments. “Compared to other wide and ultrawide bandgap semiconductors, diamond can lead to faster-switching and higher-rated device and power module technologies that can transform power management.” 

Reimagining 50-year-old tech: Diamond PhotoConductive Semiconductor Switch

The photoconductive semiconductor switch (PCSS) was invented in 1970. Revolutionary at the time, Bayram’s team have updated the design and materials. As well as using diamond as a key component material, they also changed the structure of the device itself, incorporating a buried metallic conductive channel that enables higher currents. The devices are triggered by ultraviolet light sources, a technology pioneered in the Laboratory for Optical Physics and Engineering (co-PI, ECE professor Andrey Mironov). 

Bayram summarizes: “We are not limited by traditional photoconductive switch technologies, because we have a new way of light triggering and current conduction.”

“We're trying to modify a very simple structure that has existed for over 50 years, utilizing both a novel material, diamond, and a new device structure that we think will overcome the restraints traditionally put on these kinds of devices,” adds ECE graduate student Zhuoran Han. 

They aim to create a device that can be a critical component in higher-temperature, more efficient and reliable power electronics. Professor Can Bayram leads the project, and his team at The Grainger College of Engineering includes ECE professors Andrey Mironov and Jean-Pierre Leburton, and ECE graduate students Zhuoran Han and Jaekwon Lee. The device packaging is led by Stony Brook University co-PI Professor Fang Luo. The team will collaborate with Opcondys, Inc. of Manteca, CA, to perform high power testing.

Cross-stack innovation: Optically-controlled semiconductor transistor 

Shaloo Rakheja’s team aims to develop an optically-controlled semiconductor transistor enabling future grid control systems to accommodate higher voltage and current.

The project will develop and optimize the technology of the Diamond Optically Gated Junction Field Effect Transistor (DOG-FET). This device will improve the control, resiliency and efficiency of future grid architectures that require higher voltage and higher current devices operating at higher speeds. The device innovates on previous versions of optically-gated transistors, for example by using light to modulate rather than control conductivity.

“We have the opportunity for a true cross-stack integration of new research ideas in the area of diamond power electronics and I am excited to help the DOG-FET technology mature with our team members,” Rakheja comments. “It is exciting to work on this truly transformative concept – DOG-FET has shown promise to deliver 10x better performance compared to current state-of-the-art solutions.”

Read more about the ULTRAFAST projects in the ARPA-E press release.