The Investigation Of GaN Based Materials Quality And LED Opto-electronic Property

GaN besed semiconductor materials exhibit some advantages in large bandgap, highly thermal conductivity and stable properties.They have already widelyused in high temperature power device, high frequency microwavelength deviceand light emitting diodes. At present, LED materials are fabricated from GaNbesed materials on sapphire substrates. There are some lattice mismatchesbetween GaN based materials and sapphire substrate. Device properties aresignificantly impressed by crystallization quality. So GaN buffer layers is thebasement of the whole luminescence materials growth. P type doping isassociated with LED device functions. Both of them are the important stages inthe growth of luminescence materials.This thiese investigated the growth of GaN besed semiconductor materialsby organometallic vapor phase epitaxy, characterized the materials preperties and device functions by atomic force microscope, high resolution X raydiffraction, hall testing, in-situ growth monitoring curve and chip testor. Themain content contains two hands:1. The investigations is about GaN bufferlayers growth on sapphire substrates. The relation between the nitridation time atlow temperature and the quality of epitaxial layer was studied. We summariedthe law of nitridation on the crystalization quality and speculated the modelaccording to these testing results.2. The other investigation is about p-typedoping in AlGaN. The effect of doping concentration on LED optical andelectrical properties was investigated, and the optimized process parameters ofCp2Mg doping were obtained. The reason was revealed that blue LED opticaland electrical properties were influenced by Mg doping concentration of AlGaNelectronic blocking layers.