InGaN/GaN Multiple Quantum Wells Materials as Well as Blue and Green LEDs

InGaN/GaN quantum wells are commonly used in III-nitride based blue or green LED chips. Back in the earlier days, it was difficult for GaN materials to be doped for the formation of high crystal quality p-type GaN. In 1986, Hiroshi Amano and Akasaki et al. [1] demonstrated GaN films with a good surface structure and high crystal quality by MOCVD through low-temperature AlN buffer epitaxial layer. In 1989, Amano et al. [2] used low-energy electron irradiation (LEEBI) technology and successfully achieved p-type doping of GaN materials. These breakthrough technologies accelerated the development of LED. This led to the rapid progress in terms of output power, quantum efficiency, spectral quality, etc. However, InGaN/GaN multiple quantum wells LEDs also face many problems such as the polarization effects, quantum confined Stark effect (QCSE), and carrier localization effect. Both the localization effect and the QCSE affect the spontaneous emission of InGaN/GaN multiple quantum wells. Polarization effect and QCSE in InGaN/GaN multiple quantum wells materials become even more obvious with the increase of In incorporation. The development of semi-polar and non-polar LEDs can effectively alleviate these effects on nitride LEDs performance.