Engineering news
Semiconductor design is usually based on either trial and error or simulations, which provide the basis for their manufacture. But it’s often difficult to quantify the accuracy for the simulations.
"Semiconductors can be made to conduct positive or negative charges and can therefore be designed to modulate and manipulate current,” says Professor Martin Kuball of the University of Bristol's School of Physics.”However, these semiconductor devices do not stop with silicon, there are many others including gallium nitride (used in blue LEDs for example).
"These semiconductor devices, which for instance convert an AC current from a power line into a DC current, result in a loss of energy as waste heat – look at your laptop for example, the power brick is getting warm or even hot. If we could improve efficiency and reduce this waste heat, we will save energy.”
But it’s been difficult for scientists to figure out how to make these devices more efficient without an insight into their inner workings. "One applies a voltage to an electronic device, and as a result there is an output current used in the application,” Kuball continues. “Inside this electronic device is an electric field which determines how this device works and how long it will be operational and how good its operation is. No one could actually measure this electric field, so fundamental to the device operation. One always relied on simulation which is hard to trust unless you can actually test its accuracy."
In a new study published today in the journal
Nature Electronics, Kuball and colleagues outline how to precisely quantify this electric field, which should enable them to find the optimal design in which electrical fields do not exceed the critical value which would result in degradation or failure. This new measurement technique will make it easier to use emerging semiconductor materials, underpinning more efficient power electronics in solar or wind-turbine stations, electric cars, trains and planes.
"Considering that these devices are operated at higher voltages, this also means electric fields in the devices are higher and this in turn means they can fail easier,” says Kuball. “The new technique we have developed enables us to quantify electric fields within the devices, allowing accurate calibration of the device simulations that in turn design the electronic devices so the electric fields do not exceed critical limits and fail."
Next, his team will work with industry to apply the technique in real devices, and they have partnered with the US Department of Energy’s ULTRA centre to make ultra-wide bandgap device technology a reality. "This development helps the UK and the world to develop energy-saving semiconductor devices, which is a step towards a carbon-neutral society," Kuball added.
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