Breakthrough electronic engineering technique ‘is step towards carbon neutral society’

Lower levels of energy loss and more accurate design could result in far more efficient technology, scientists say

Researchers developed new optical tools to quantify electric fields in semiconductor devices (Yuke Cao/University of Bristol)

A scientific breakthrough could make our electronic devices faster, more reliable and significantly less power hungry, paving the way towards a less polluting future for our species, scientists have said.

The development, led by a research team at the University of Bristol, is based on the twin advancements of new semiconductor materials, which control electric currents, and new accurate remote measuring of the electronic fields they produce when in use.

Semiconductors, such as silicon, are widely used in electronic devices for essential components such as transistors and diodes.

To date, semiconductor design has been a mixture of trial and error, and use of imprecise simulations which aim to provide estimates of how the material will respond when the electronic device they are in is in use.

It has often been unknown how accurate these simulations are, meaning engineers had to allow for excess energy, but the new technique provides certainty on how semiconductors respond. In turn this will provide new exactitude on how components can be used, making them much more efficient.

Professor Martin Kuball of the University of Bristol’s School of Physics said: “Semiconductors can be made to conduct positive or negative charges and can therefore be designed to modulate and manipulate current. 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.”

He added: “One applies a voltage to an electronic device, and as a result there is an output current used in the application. 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."

The research team said that in order to maximise devices’ performance and ensure they are long lasting, it is important to use these new materials and find the optimal design, where electric fields do not exceed critical values, at which point they could be damaged or fail.

Using gallium nitride and gallium oxide rather than silicon, allows circuits to operate at higher frequency and at higher voltages, opening the door to new kinds of circuits which reduce overall energy loss.

The development of an optical tool enables the direct measurement of electric field within these new devices.

This precise measuring ability can be used to underpin future efficient power electronics in applications such as solar or wind turbine stations feeding into the national grid, as well as in electric cars, trains and planes, the scientists said.

Reduced energy loss also means societies do not need to produce as much energy in the first place.

Professor Kuball said: “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.”

But he added that “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”.

The research team are working with industry and other academics to bring the new technology to market, and said they will work with partners within the $12m US Department of Energy ULTRA centre.

"This development helps the UK and the world to develop energy saving semiconductor devices, which is a step towards a carbon neutralsociety," Professor Kuball said.

The research is published in the journal Nature Electronics.