Abstract
It had been believed for long time that it was almost impossible to grow a high quality GaN single crystal. This difficulty was broken through by pioneering the low-temperature deposited buffer layer technology. This achievement opened up the successful path to the discovery of p-type conduction, control of n-type conductivity and verification of quantum size effecrts. These breakthroughs have led to the novel and high-performance devices such as high-efficiency blue, green and white light-emitting diodes, long-lived blue-violet lasers, low-noise UV detectors and high-speed transistors. All of these nitride-based devices are able to operate in harsh environment because of their toughness. They also should enable a tremendous saving in energy and are suitable for the protection of the environment. Nitride semiconductors and their devices are expected to contribute to the future world. The author, who has been convinced of the tremendous possibilities of Nitrides and struggled with this difficult system while others were giving up, is so much delighted with the prosperity of the Nitride field, and feels that his dream is finally realized.
