Hanyang University announced on March 7 that a research team of Professors Shim Jong-in and Shin Dong-soo at the Department of Organic and Nano Engineering, Hanyang University ERICA Campus, Zogan Semi, Ph.D. Ryoo Woong-ryeol, Ph.D. Baek Jong-hyup's team at the Photonic Semiconductor & Display Research Division of the Korea Photonics Technology Institute developed a technology that overcomes micro LED light efficiency and durability challenges.

Through this research, the research team solved the low electricity convergence efficiency that happens in nitride semiconductor LED chips that are sized under 20μm and the largest problem of high-resolution micro-LED display development and the durability issue that shows drastic performance decrease as the running time increases.

The team implemented contactless optical luminescence and Raman spectroscopy and was able to clarify that the technical issues of micro-LED chips were based on defective charges on the etch wall and reactions due to epi-layer stretch. By epi-growing oxide semiconductor on nitride semiconductor, the research made epi-layer strain controllable so that it becomes irrelevant to the defect charge amount on the etch wall which is sensitive to the manufacturing or moving conditions.

The 10μm- and 20μm-sized blue micro-LED is a horizontal chip sole package and it shows a maximum external quantum efficiency of 53% and 45% from the public testing result and also proved the world-best quality by marking 35% in a low electricity area of 1A/cm2. (See Picture 1.) Also, it checked outstanding stability that had no performance difference in an acceleration duration test without a heat sink (100A/cm2, more than 20 hours. See Photo 2.).

Professor Shim Jong-in said, "With the newly developed technology, we not only newly established the function principle of micro-LED which is now under many spotlights as a core semiconductor of the next-generation display, and it seems that it contributed a lot to securing international competency to domestic display industry."

The research was under the support of the National Standard Technology Improvement Project by the Ministry of Trade, Industry and Energy and the Optical Convergence Industry Global Competitiveness Enhancement Project and the Ultra Large Modular Display Technology Development Project.