Professor Sang-Hyun Kim’s lab has developed a 60,000 PPI ultra-high-resolution micro-LED display production technology.
Dr. Dae-Myeong Geum has participated as the first author and their work has been published as a cover paper of international journal ‘Nanoscale’, December 28th edition. (Title of the paper: Strategy toward the fabrication of ultrahigh-resolution micro-LED displays by bonding interface-engineered vertical stacking and surface passivation)
To solve the problem of the existing development of ultra-high-resolution displays, the research team stacked a red-green-blue LED active layer in three dimensions, and then proposed a device manufacturing method that can cope with ultra-high resolution micro-LED displays using a semiconductor patterning process. Also, they have proposed a solution that can improve overall efficiency in a small pixel and solve a color interference which is problematic for vertical stacking.
The research team used a substrate bonding technology for three-dimensional stacking, and designed an insulating film with filter characteristics on the bonding surface to minimize color interference, eliminating 97% of the red-blue interference light.
Their work has shown that even vertically combined pixels can achieve high purity pixels without light interference by incorporating an insulating film. The research team demonstrated the ability to achieve resolutions above 60,000 PPI using the vertical patterning followed by semiconductor patterning technology.
Besides, the non-luminescent recombination phenomenon on the semiconductor surface, which can be problematic in the small LED pixels, was thoroughly investigated through time-resolved photoluminescence analysis and computational simulation to provide a meaningful direction to improve the efficiency of the small LED.
Professor Sang-Hyun Kim said, “This is the first research to demonstrate the possibility of producing ultra-high resolution pixels using a semiconductor process. This research shows the importance of cooperation between the semiconductor and display industry. We will continue to work on the development of ultra-high-resolution future displays through future research.
The research was supported by the Korea Research Foundation’s basic research projects in science and engineering, and climate change response technology development projects.
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