As global electricity demand grows, improving power electronics is crucial for making energy systems more efficient and reliable.
Scientists are working to develop better materials for these electronic components to reduce energy loss and improve performance.
One key area of research focuses on wide-bandgap materials, such as aluminum gallium nitride (AlxGa1-xN).
These materials can handle more power while reducing heat and electrical losses, making them ideal for next-generation power electronics.
However, growing high-quality AlxGa1-xN is challenging because it requires a compatible base, or substrate, to support its structure.
If the substrate is not well-matched, defects called dislocations can form, reducing performance.
A team of researchers from the National Renewable Energy Laboratory (NREL), Colorado School of Mines, and Oak Ridge National Laboratory explored a promising solution—growing AlxGa1-xN on tantalum carbide (TaC), an electrically conductive and well-matched substrate.
Their study, published in PRX Energy, showed that TaC could help reduce defects and improve energy efficiency in power electronics.
Why tantalum carbide?
Substrate engineering is complicated, and past efforts to reduce dislocations often made devices more complex and less efficient. The researchers proposed that transition metal carbides, like TaC, could provide the ideal conditions for growing AlxGa1-xN. Their findings showed that:
- TaC closely matches the structure of AlxGa1-xN, reducing defects.
- TaC has excellent thermal and electrical conductivity, improving energy efficiency.
- Both materials expand and contract similarly with temperature changes, preventing cracks and defects during growth.
The team successfully grew AlxGa1-xN on TaC substrates using a method called radio frequency sputtering and then strengthened the structure through high-temperature annealing. These techniques improved the quality of the material, bringing power electronics one step closer to real-world applications.
Another group of NREL scientists, led by Sharad Mahatara and Stephan Lany, used computer models to better understand how different materials interact at the atomic level. Their research, published in Physical Review Applied, focused on designing heterostructural interfaces, where two different crystal structures meet.
Using a specialized algorithm, they studied how atoms stack at the boundary between TaC and AlxGa1-xN. They used advanced calculations to predict the best conditions for growing high-quality materials, helping engineers control polarity, which influences electron movement in devices.
By combining experimental and computational research, scientists are paving the way for more efficient and powerful electronic devices. This work could lead to energy-saving advancements in electrical grids, renewable energy systems, and everyday technology.
“We’re excited about the potential of these materials,” said NREL’s Dennice Roberts. “This research offers a creative solution to a long-standing challenge, and we look forward to future developments in power electronics.”
