"Two Lights in One Chip"...Development of 'Dual-Infrared' LED Achieving Simultaneous Short and Mid-Wavelength Emission [Reading Science]

Alleviating Lattice Distortion Through Precise Atomic Arrangement Control
Expectations for Miniaturized Equipment and High-Precision Sensors

A "dual-infrared" light-emitting diode (LED) capable of simultaneously emitting both short-wavelength and mid-wavelength infrared light from a single chip has been developed by a Korean research team. This achievement, which involves controlling the lattice mismatch issue that occurs when integrating semiconductors of different wavelengths into a single structure at the atomic level, is expected to serve as a foundation for next-generation infrared sensing and imaging technologies.

The National Research Foundation of Korea (NRF) announced that Dr. Lee Sangjun's research team at the Korea Research Institute of Standards and Science (KRISS), in collaboration with Stanford University in the United States and Helmholtz University in Germany, precisely controlled the atomic arrangement within compound semiconductors to realize an LED that simultaneously emits short-wavelength (1-3 μm) and mid-wavelength (3-5 μm) infrared light from a single chip.

Schematic diagram and emission wavelengths of the monolithically integrated multi-band LED. The monolithically integrated multi-band LED has a structure in which two multiple quantum wells emitting different wavelengths are stacked, simultaneously emitting infrared light at 2.87 μm and 3.18 μm. Illustration description and provided by: Byungseon Jeon, Principal Researcher at Korea Research Institute of Standards and Science

This research was supported by the Next-generation Compound Semiconductor Core Technology Development Project, promoted by the Ministry of Science and ICT and the National Research Foundation of Korea. The results were published online in the international journal Advanced Materials in the field of materials engineering on January 13.

Overcoming Lattice Mismatch Limits...First Realization of 'Multi-band'

Conventional infrared LEDs typically emitted light only in a single band. To achieve different wavelengths, it was necessary to stack different semiconductor materials, but this process resulted in crystal defects and cracks caused by differences in lattice constants, leading to limitations in light emission efficiency.

The research team applied a multiple quantum well (MQW) structure to indium arsenide antimonide (InAsSb), a material commonly used for mid-wavelength infrared applications, and combined this with quantum barrier design and strain engineering. In particular, by doping with antimony (Sb), they finely adjusted the atomic bond lengths and angles, which reduced local strain energy and alleviated lattice distortion.

Analysis using atomic-resolution transmission electron microscopy and AI-based atomic simulation showed that doping significantly reduced the density of dislocations and point defects, and enhanced the quantum confinement effect, making it possible for a single LED to emit both wavelengths simultaneously.

The actual device implemented simultaneously emitted at 2.87 μm and 3.18 μm wavelengths with outputs of 14 μW and 30 μW, respectively. The research team also developed a "manufacturability map" that optimized the emission wavelengths and strain energy according to quantum well thickness and antimony composition, and used it to fabricate additional devices capable of simultaneous emission in the 2.63 μm and 3.34 μm bands.

Expansion to Bio, Environmental, and Defense Applications

The ability to realize multiple wavelengths simultaneously in a single device is expected to enable equipment miniaturization, cost reduction, and resolution of signal synchronization issues. In particular, there is significant potential for application in fields that require multi-band infrared, such as bio-diagnostics, environmental gas analysis, smart process sensors, automotive LiDAR, and military surveillance equipment.

Byungseon Jeon, Principal Researcher at Korea Research Institute of Standards and Science, stated, "For multiple wavelengths to be stably emitted from a single LED, the intensity and quality of each band must be precisely controlled," adding, "We will further advance the technology to achieve both high output and high efficiency simultaneously."

This achievement is regarded as an internationally recognized example demonstrating that semiconductor optoelectronic devices can be predictively designed through atomic-level structural control.

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