论文部分内容阅读
采用微区拉曼光谱对生长在湿法腐蚀获得的无掩膜周期性图形蓝宝石衬底上GaN材料做了研究,结果显示,侧向外延生长区域具有较低的压应力。采用湿法腐蚀结合原子力显微镜对材料的位错进行了表征,侧向外延区域显示了低的位错密度,具有较高的晶体质量。另外通过对不同生长区域的拉曼纵光学声子与等离子体激元形成的耦合模高频支进行拟合,结果显示侧向外延区域具有较低的背底载流子浓度。研究认为,由于采用图形衬底,侧向外延区域悬空生长降低了位错密度,同时侧向外延区域不与蓝宝石接触,因此采用该方法生长的GaN材料具有较低的压应力和较低的背底载流子浓度。
Micro-region Raman spectroscopy was used to study the GaN material grown on the mask-free periodic patterned sapphire substrate by wet etching. The results show that the lateral epitaxial growth region has lower compressive stress. The dislocations of materials were characterized by wet etching combined with atomic force microscopy. The lateral epitaxial regions showed low dislocation density and high crystal quality. In addition, fitting of the high-frequency coupled modes formed by Raman longitudinal optical phonons and plasmon polaritons in different growth regions shows that the lateral epitaxial region has a lower background carrier concentration. It is considered that the GaN material grown by this method has a lower compressive stress and a lower back due to the use of a patterned substrate, the dangling growth in the lateral epitaxial region reduces the dislocation density and the lateral epitaxial region does not come in contact with the sapphire Bottom carrier concentration.