Enhance the performance of UV LEDs with zinc oxide microfiber

Researchers at the Georgia Institute of Technology used zinc oxide microfibers to significantly improve the efficiency of ultraviolet light emitting diodes.

The first LED devices were enhanced by generating electricity in a piezoelectric material using a phototronic effect .

"By using this effect, we can improve the efficiency of external devices (by a factor fourfold) by up to 8%," said Professor Zhong Lin Wang, Faculty of Materials Science and Engineering Technology, Georgia Institute of Technology, USA.

"From a practical point of view, this new effect can have a lot of impact on the photovoltaic process, including improvements in the energy savings of lighting equipment , " Wang added.

High performance UV light emitting diodes are required for applications in: chemical, biological, aerospace, military and medical technologies. Although the internal quantum efficiency of LEDs can be as high as 80%, the external efficiency for a single conventional LED thin film at the pn junction is only about 3%.

By using micro-zinc oxide microfibers, researchers have created a piezoelectric potential in conductors that are used to regulate the charge capacitance and enhance charge carriers in LEDs. .

Because of the polarization of ions in the crystals of piezoelectric materials, such as: zinc oxide, the material of piezo-electric potential, formed from structures subjected to mechanical compression. as resistant to electrical overload. In the gallium nitride LEDs, the researchers used local piezoelectric potential to regulate the charge at the pn junction.

This effect increases the electron and hole recombination rates to create photons, improving the external performance of the device through higher-than-normal light emission.

"The effect of using piezoelectric potential is to adjust the charge at the pn junction," Wang said. "This opens up a new field by using piezoelectric effects to adjust the optoelectronic devices."