Researchers suggest reverse LEDs to break into cooling

Researchers at the University of Michigan have unveiled a solid-state cooling system intended for future semiconductors, based on a surprisingly simple concept: operating a light-emitting diode (LED) at the same time. towards.

As its name indicates, a light emitting diode (LED) is an electronic component that emits light when electricity is applied in the right direction. Like the non-light emitting diode, applied electricity in the wrong way should not do anything – but that's not what the researchers at the University of Michigan, supported by the Department of Energy and the US Army Research Office, have discovered.

Professors Pramod Reddy and Edgar Meyhofer, who jointly lead the work, are relying on the work of Nobel Laureate Arthur Ashkin to reverse the electrodes of an infrared light emitting diode in order to take advantage of 39, an unknown physical phenomenon. : & # 39;The LED, with this reverse bias trick, behaves as if it were at a lower temperature,"Reddy explains, removing not only its usual emittance of infrared light, but also the heat radiation it should produce when it was just at room temperature.

The trick is well known, but it was difficult to prove that the diode actively absorbed infrared light from nearby objects – and thus to cool it down – which involved placing the two at a distance of a few tens of nanometers . & # 39;At this proximity,"the university explains,"a photon that would not have escaped the object to cool can pass in the LED, almost as if the space between them did not exist.& # 39;

The two men, alongside their team, built a tiny calorimeter – a device to measure the energy variations – and placed it next to an infrared LED of the size of ## EQU1 ## 39, a grain of rice. Once the light-emitting diode was reverse biased, the effect was measured: the photons were absorbed by the calorimeter, while the tiny space between the two objects prevented the conduction from returning the thermal energy. Result: a cooling effect measured at 6 watts per square meter (6 W / m²) which, according to the team, could theoretically be increased up to 1,000 W / m².

Like many advances of this type in the lab, there is still a long way to go before the technology is ready for commercialization – but the team says that it could prove useful to dissipate quickly the heat of future processors in small devices, including smartphones.

The team's work was published in the journal Near-field photonic cooling by controlling the chemical potential of photons. Nature.

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