LED technology of epitaxial structure and extension techniques TFT Display Module

(1) Droop effect
After several years of development, LED epitaxial layer structure and epitaxy technology is relatively mature, the internal quantum efficiency of up to 90%. However, in recent years, with the rise of high-power serial display modules chips, LED injection under the big decline in the quantum efficiency has aroused wide concern, this phenomenon is vividly called Efficiency Droop. The industrial sector is concerned, can guarantee to solve Droop in power under the premise further reduce the chip size, to reduce costs. For academic purposes, Droop effect is to attract scientists to study the cause of the hot spot.
Unlike conventional semiconductor optoelectronic materials, GaN-based LED Efficiency Droop causes are complex, and the corresponding lack of effective means of settlement. After exploring the researchers to compare tendencies are several reasons: the carrier localization solution, carriers from the active region of the leak or spill, and Auger recombination. Although specific reason is not clear, but it was found that using a wide quantum well to reduce the density of carriers and optimization of the p-type electron blocking layer region is a means to relieve Droop effect.
(2) quantum well active region
InGaN / GaN quantum well active region is the core of LED epitaxial materials, growth InGaN quantum well is the key to control the quantum wells stress, reduce polarization effects. Conventional growth technology include: low MQW In composition of InGaN growth before the pre-stress release well as carriers and tanks, heating growing a GaN barrier layer to improve the crystal quality of the barrier layer, the growth of a lattice-matched barrier layer InGaAlN or growth stress complementary InGaN / AlGaN structure. The number of quantum wells is no uniform standard, the industry uses the number of quantum wells from 5-15 have, the final result is not very different, a small number of wells in a small injection under the Graphic LCD Module is more efficient, while a few more wells The LED in the large injection efficiency.