Research Of Material Characteristic Of GaN Based LED And Design Of Chip Structure

Light-emitting diode (LED) is a widely used light source. It got the advantage of low-cost, long-life, environmental protection in the development of the semiconductor solid-state lighting. In order to let the solid state lighting be accepted by the market, LED with high efficiency and stability must be improved.To explore the market potential of the solid state lighting, LEDs need to improve the efficiency to meet the needs of the market. LED efficiency consists of the internal quantum efficiency and light extract efficiency. One of the major technical problems is that the internal quantum efficiency will drop sharply when the chip is under large current injection or high temperature. The internal quantum efficiency is depending on the micro-structure characteristics of the internal MQW crystal materials. The internal quantum efficiency is one of the most important points to have breakthrough in the research of the solid state lighting technology. At the same time the chip stability is greatly depend on the research of the micro-structure of the MQW.This paper introduced the basic structural characteristics and physical and chemical characteristics of GaN material. GaN epitaxial structure and the properties of GaN-based high-performance chips are discussed in this paper. The working principle and main applications of transmission electron microscopy is introduced first, and then the TEM images were analyzed, including GaN MQW, V-defect and high-Al defect. Then PL and EL of a variety of GaN samples is showed in this paper, and the reason spectrum red-shift and blue shift is explained. CASTEP program is discussed in the end. In the part of structural design, this paper presents three high-efficiency LED chip design structures, which are based on double photonic crystals LED chips, based on the model of micro-LED chips, based on the high-power laser stripping substrate LED chips. Photonic crystal theory, theory and Monte Carlo laser stripping theory are discussed and the new LED chips are designed based on them. Double-photonic crystals can provide better reflection layer. Microspheres LED can get high quantum efficiency with large structure parameters. The high power LED involved laser-lift-off technology can get a very good thermal radiation effect.