Researches On AlGaInN QW LED

White Light Emitting Diode is considered to be the next generation lighting instead of the incandescence lighting because of high efficiency, long life, small volume, easy integration, low driver, no pollution etc. But nowadays WLED is based on blue LED and yellow YAG phosphor, or composed of red, green, yellow LEDs. These methods not only raise the package costs, but also make the control circuit very complicated. Moreover,'halo effect'in phosphor WLED is not suitable for lighting. However, WLED which emit white light directly from the chip do not has these defects. This paper presents the theoretical and experimental researches on the AlGaInN LED. The main contents are as follows:(1) The strain effects, piezoelectric field effects and Coulomb interaction of AlGaInN quantum well (QW) are investigated. It is found that they are all important emission mechanisms which can not be neglected in AlGaInN QW. Based on the K·P method theory and a self-consistent calculation, the relationship between QW structure and gain property is quantified. Detailed analyses and calculation provide a good basis for further research.(2) A novel WLED constructed of two active regions or three active regions is researched, which emit white light directly from the LED. Based on the physical model and chromaticity theory, the QW structure is optimized. The lowest color temperature could be 5500K. The best color-rendering index is higher than 85. The calculation provides a good guide for the growth of a real LED device.(3) The experiments on LED packaging and testing are pursued. The LED parameters are good. The testing results are also in accordance with the theory calculation.