"UV LED Limitations Broken"... 20 Times More Efficient 'Deep Ultraviolet Light Source' Developed [Science Insight]

Implementing Quantum Wells by Twisting van der Waals Materials
Paving the Way for Next-Generation Hygiene Technologies Against Infectious Diseases

A new material that enables high-efficiency emission in the deep ultraviolet region—a feat that was virtually impossible with conventional semiconductor technology—has been developed by a team of Korean researchers. This achievement addresses the longstanding issue of low efficiency in ultraviolet light-emitting diodes (LEDs), and its potential application as a next-generation sterilization technology for infectious disease control is drawing significant attention.

According to the Ministry of Science and ICT, a joint research team led by Professor Kim Jonghwan of Pohang University of Science and Technology and Cho Moonho, director at the Institute for Basic Science, has developed a new material that improves deep ultraviolet emission efficiency by a factor of 20 compared to existing materials. The results of their research have been published in the world-renowned academic journal Science.

Schematic diagram of a moiré quantum well formed by twisting and stacking van der Waals semiconductor boron nitride (BN). Provided by the research team

‘Quantum Wells’ Formed by Twisting and Stacking... 20 Times Higher Emission Efficiency

The core of this research lies in the "twisted stacking structure." The team used boron nitride (BN), a van der Waals semiconductor material whose atomic layers are bound by weak forces, and discovered that stacking these layers at different angles creates a new quantum structure that can strongly confine electrons. This structure, called a "moire quantum well," traps electrons within nanometer-scale spaces, enabling efficient emission of high-energy light.

Previously, ultraviolet LEDs extended into the deep ultraviolet region by using aluminum gallium nitride (AlGaN) materials, which incorporate aluminum into gallium nitride (GaN)-based semiconductors. However, in the 200–240 nm range, emission efficiency sharply dropped to below 1%, representing a significant limitation.

The research team overcame this limitation with the BN moiré quantum well structure. Under the same conditions, it achieved more than 20 times higher emission efficiency than conventional AlGaN-based structures. In addition, they confirmed that the emission wavelength could be controlled simply by adjusting the twisting angle. This means performance can be tuned through structural design alone, without altering the chemical composition.

This achievement was also demonstrated in actual device implementation. The team successfully created an LED by applying graphene electrodes and observed clear deep ultraviolet emission even at low current. This result shows that the technology can move beyond the laboratory and be developed into practical optoelectronic devices.

An image and spectrum showing strong deep ultraviolet emission in the 220-240nm wavelength range upon applying voltage to a deep ultraviolet LED device based on graphene electrode-applied boron nitride (BN) moiré quantum wells. Provided by the research team

In particular, deep ultraviolet light in the 200–230 nm wavelength range is known to be relatively safe for humans, as it cannot penetrate the stratum corneum of the skin, while still providing powerful sterilization effects. Currently, commercial ultraviolet light (around 260 nm) poses risks to humans upon exposure, which limits its use. Therefore, this technology has significant potential as a next-generation hygiene solution that could enable continuous sterilization in hospitals, schools, public transportation, and other multi-use facilities.

Professor Kim Jonghwan of Pohang University of Science and Technology stated, "This is a conceptual transformation that extends quantum phenomena observed in van der Waals materials from two dimensions to three dimensions. It will serve as a starting point for the design of next-generation optoelectronic devices and quantum materials."

This research was carried out with support from the Ministry of Science and ICT’s Basic Research Program and projects funded by the Institute for Basic Science. The team plans to expand their research to develop high-efficiency deep ultraviolet light source devices and explore a variety of quantum optoelectronic applications in the future.

This content was produced with the assistance of AI translation services.