Rush-hour traffic is part of life in most metropolitan areas in the US. The presence of large numbers of people traveling in the same general direction at the same time is bound to result in congestion and frustration. Picture that same rush hour during the summer. Air conditioners crank as heat ripples off the blacktop and, inevitably, somewhere along the way a car is pulled to the side of the road, steam pouring from under the hood.
Overheating is an issue for much of the technology that defines modern life. Cars, computers, mobile phones—all are subject to the effects of too much heat. As technology continues to speed up and devices get smaller, this heat problem compounds as internal parts shrink and move closer together. Jian Liu, assistant professor of physics and astronomy, is working to address this issue with his JDRD project.
It all starts with an electron. Transistors, the building block of modern electronics and technology, work by moving an electron back and forth across an interface. This switching action can be sped up by decreasing the distance the electron has to travel through the interface, letting the device operate faster. This is where heat can become a problem.
“When the electron travels, it generates heat because it interacts with other atoms. The electron is trying to go and at some point it’s going to hit an atom, causing the atom to vibrate,” said Liu. “Basically, you’re transferring the energy from the electron to the atom and that’s how it generates heat.”
Because heat has the ability to affect device performance, its management is an important factor in technology development. Liu’s team hopes to find a way to predict how heat is moved within a device, laying the groundwork for more effectively controlling how and where heat is transported out of the device.
“If you can control heat transport, you can have an electronic device that works faster. Then you can maybe pack your devices into a more confined area and make sure there’s no hot spot,” said Liu.
His JDRD team is working to build a prototype that will use the same interface for both electron and heat movement. Once complete, the prototype will be given to Lucas Lindsay, materials research scientist at ORNL, for experimental testing and comparison with computational predictions. The teams hope to have generated preliminary data by the end of the funding year.