Institute of Industrial Science
A research group led by Prof. Fujioka, the Institute of Industrial Science, The University of Tokyo, have developed a technique for fabricate of full-color light emitting diodes (LEDs) on large-area flexible metal foils for next-generation displays.
Recently GaN-based light-emitting diodes (LEDs) have been widely accepted as highly efficient solid-state light sources capable of replacing conventional incandescent and fluorescent lamps. However, their applications are limited to small devices because their fabrication process is quite expensive since it involves epitaxial growth of GaN by metal-organic chemical vapor deposition (MOCVD) on single crystalline sapphire wafers. If a low-cost epitaxial growth process such as sputtering on a metal foil can be used, it will be possible to fabricate large-area and flexible LED displays at low cost.
Prof. Fujioka's group has developed a new technique called pulsed sputtering which can handle industry-scale growth of GaN under the support of JST-ACCEL funding program. The group fabricated blue, green, and red LEDs on metal foils and confirmed their successful operation. The results indicate that GaN films prepared on metal foils by this method can be used in fabrication of future large-area flexible LED display.
This work is detailed in the paper: "Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils", from Scientific Reports 7, 2112 (2017) published on May 18, 2017.
Hyeryun Kim, Jitsuo Ohta, Kohei Ueno, Atsushi Kobayashi, Mari Morita, Yuki Tokumoto, and Hiroshi Fujioka, "Fabrication of full-color GaN-based light-emitting diodes on nearly lattice-matched flexible metal foils", Scientific Reports,doi: 10.1038/s41598-017-02431-7
Article link https://www.nature.com/articles/s41598-017-02431-7
Article link https://www.iis.u-tokyo.ac.jp/ja/news/2716/
Hiroshi Fujioka, Professor