柱状与孔状图形衬底对MOVPE生长GaN体材料及LED器件的影响

在柱状图形蓝宝石衬底（PSS-p）和孔状图形蓝宝石衬底（PSS-h）上外延了GaN体材料和LED结构并进行了详细对比和分析.X射线衍射仪（XRD）和原子力显微镜（AFM）测试结果表明，PSS-h上体材料的晶体质量和表面形貌都优于PSS-p上体材料的特性，通过断面扫面电子显微镜（SEM）照片看出PSS-h上GaN的侧向生长是导致这种差异的原因.另外，基于PSS-p和PSS-h上外延的LED材料制作而成的器件结果表明，其20?mA下光功率水平相比普通蓝宝石衬底（CSS）分别提高了46%和33%.通过变温光荧光 关键词： 蓝宝石图形衬底 氮化镓 发光二极管 侧向生长

Influence of pillar-and hole-patterned sapphire substrates on MOVPE grown GaN bulk and LED structures

Bulk GaN material and LED structures on pillar-patterned sapphire substrates （PSS-p） and hole-patterned sapphire substrates （PSS-h） were grown by MOCVD and the characteristic was compared in detail. X-ray diffraction and atomic force microscope measurements show a better crystal quality and surface morphology of GaN on PSS-h than that of GaN on PSS-p, which is due to the lateral growth of GaN on PSS-h observed from cross-sectional scanning electron microscopy. Furthermore, the output power of LED on PSS-p and PSS-h with 20 mA injection current are 46% and 33% higher than LED on conventional sapphire substrate, respectively. The temperature-dependent photoluminesence measurements indicate that the internal quantum efficiencies of all samples are quite close. Therefore, the airgaps between GaN and PSS-h act against the improvement of light extraction efficiency.