高亮度白光LED用外延片的新进展

文章首先介绍了发光二极管（LED）的内量子效率、外量子效率的基本概念和提高量子效率的基本方法，接着对LED外延的结构和方法做了简要介绍．文章的第三和第四部分则着重介绍了提高内、外量子效率的外延方法，这些方法包括外延结构的优化，侧向外延生长，SiC和GaN衬底的生长，AIInGaN四元系有源区生长，非极性面、半极性面的外延，表面粗化结构生长，图形化二次外延结构．图形化蓝宝石衬底上的外延，提高载流子注入效率的结构和组分设计．文章的第五部分则介绍了基于可靠性和成本考虑的其他新型外延结构，第六部分介绍了提高LED可靠性的外延方法．最后得出结论：采用非极性面的GaN衬底，生长优化的LED结构，并结合光子晶体技术，可望取得突破性进展．

New Progress in wafer epitaxy technologies for high-brightness white LEDs

The concept of internal and external quantum efficiency of light emitting diodes (LEDs) and the basic ways to improve this are first introduced. The epitaxial structure and growth of LED wafers are then briefly described, with emphasis on the techniques to enhance the quantum efficiency. These include epitaxial structure optimization, lateral epitaxial overgrowth, growth on SiC or GaN substrates, growth of an AlInGaN active layer, epitaxy on non-or semi-polarized planes, growth of surface-roughening structures, regrowth on patterned templates, growth on patterned sapphire substrates, structural and composition designs to improve the injection efficiency into the active layer, and so on. Various novel epitaxial structures are discussed with regard to cost and reliability, and methods in growth to improve the reliability are introduced. Finally, we conclude that a breakthrough in semiconductor lighting can be achieved by a combination of non-polarized substrates, optimized epitaxial structures and photonic crystal technology.