Si衬底InGaN/GaN多量子阱LED外延材料的微结构

Microstructure of an InGaN/GaN Multiple Quantum Well LED on Si(111) Substrate

用透射电子显微镜(TEM)和X射线双晶衍射仪(DCXRD)对在Si(111)衬底上生长的InGaN/GaN多量子阱(MQW)LED外延材料的微结构进行了观察和分析.从TEM高分辨像观察到,在Si和AlN界面处未形成SixNy非晶层,在GaN/AlN界面附近的GaN上有堆垛层错存在,多量子阱的阱(InGaN)和垒(GaN)界面明锐、厚度均匀;TEM和DCXRD进一步分析表明MQW附近n型GaN的位错密度为108cm-2量级,其中多数为b=1/3〈1120〉的刃位错.

The microstructure of an InGaN/GaN multiple quantum well （MQW） LED on Si （111） substrate is characterized using transmission electron microscopy （TEM） and double crystal X-ray diffraction （DCXRD）. High-resolution TEM shows that there is no amorphous layer at the AIN/Si interface. However,stacking faults in the GaN film appear close to the GaN/ A1N interface. A very sharp interface between the InGaN and GaN layers reveals the good quality of the MQW material. In addition,TEM and XRD indicate that the dislocation density in the n-GaN layer near the MQW is on the order of 10^8 cm^-2, and the major dislocation is pure edge dislocation （b = 1/3 （1150））.