technologyfrom left to right undated photos of japaneseborn researchers isamu akasaki hiroshi amano and a handout photo of shuji nakamura released by university of california via afp red and green diodes had been around for a long time but without blue light white lamps could not be created despite considerable efforts both in the scientific community and in industry the blue led had remained a challenge for three decades they succeeded where everyone else had failed the invention of the blue led is just 20 years old but it has already contributed to create white light in an entirely new manner to the benefit of us all akasaki worked together with amano at the university of nagoya while nakamura was employed at nichia chemicals a small company in tokushima their inventions were revolutionary incandescent light bulbs lit the 20th century the 21st century will be lit by led lamps white led lamps emit a bright white light are long lasting and energy efficient they are constantly improved getting more efficient with higher luminous flux measured in lumen per unit electrical input power measured in watt the committee said when akasaki amano and nakamura arrive in stockholm in early december to attend the nobel prize ceremony they will hardly fail to notice the light from their invention glowing in virtually all the windows of the city blue light remained a challenge for three decades when they obtained bright blue light beams from their semiconductors the gates opened up for a fundamental transformation of illumination technology incandescent light bulbs had lit the 20th century the 21st century will be lit by led lamps according to the committee to make the invention the laureates built their equipment themselves learned the technology and carried out thousands of experiments most of the time they failed but they did not despair this was laboratory artistry at the highest level gallium nitride was the material of choice for both akasaki and amano as well as for nakamura and they eventually succeeded in their efforts early on the material was considered appropriate for producing blue light but practical difficulties had proved enormous no one was able to grow gallium nitride crystals of high enough quality nonetheless akasaki was convinced by previous experience that the choice of material was correct and continued working with amano who was a phd student at nagoya university nakamura at nichia also chose gallium nitride before the alternative zinc selenide which others considered to be a more promising material in 1986 akasaki and amano were the first to succeed in creating a highquality gallium nitride crystal by placing a layer of aluminium nitride on a sapphire substrate and then growing the high quality gallium nitride on top of it by coincidence akasaki and amano discovered that their material was glowing more intensely when it was studied in a scanning electron microscope nakamura began developing his blue led in 1988 two years later he too succeeded in creating highquality gallium nitride he found his own