SWISS FEDERAL INSTITUTE OF AQUATIC SCIENCE AND TECHNOLOGY
By Dr. Sara Beck
sara.beck@eawag.ch
“LEDs were initially developed in the 1950s by German, British and American researchers working in parallel to advance the electronics, phone, TV and lighting industries. These early LEDs, which used a gallium phosphide (GaP) substrate solo or doped in nitrogen or zinc oxide, emitted visible light in the red to green ranges (Grimmeiss and Koel- mans, 1961; Gershenzon and Mikulyak, 1961; Starkiewicz and Allen, 1962). The blue LED, which would complete the color wheel, proved elusive for three decades. It wasn’t until the 1980s that a trio of Japanese researchers developed the high-output blue LED by growing high quality crystals into a multi-layer gallium-nitride (GaN)-based substrate. This feat of engineering (Figure 3), and its subsequent impact on the lighting and electronics industries, earned Isamu Akasaki, Hiroshi Amano and Shuji Nakamura the Nobel Prize in Physics in 2014 (Scientific Background on the Nobel Prize in Physics 2014).”