利用金属有机气相化学沉积(MOCVD)技术在蓝宝石图形衬底上生长GaN基蓝光LED, 并系统研究了不同中高温GaN插入层厚度对其光电性能的影响。利用芯片测试仪和原子力显微镜(AFM)表征了GaN基蓝光LED外延片的光电性能以及表面形貌。当中高温GaN插入层厚度从60 nm增加至100 nm时, V形坑尺寸从70～110 nm增加至110～150 nm。当注入电流为20 mA时, LED芯片的光功率从21.9 mW增加至24.1 mW; 当注入电流为120 mA时, LED芯片的光功率从72.4 mW增加至82.4 mW。对V形坑尺寸调控LED光电性能的相关物理机制进行了分析, 结果表明: 增大V形坑尺寸有利于增加空穴注入面积和注入效率, 进而提高LED器件的光功率。

GaN-based blue light emitting diodes (LEDs) were grown on patterned sapphire substrates by metal-organic chemical vapor deposition (MOCVD) method, and the medium-high temperature GaN interlayer with different thickness was grown between the multiple quantum wells layer and n-GaN layer. The Optical and electrical properties and surface morphology of LEDs were characterized by LED test system and atomic force microscopy(AFM), respectively. When the thickness of the medium-high temperature GaN interlayer increases from 60 nm to 100 nm, the size of V-pit enlarges from 70－110 nm to 110－150 nm. Meanwhile, the light output power of the chip increases from 21.9 mW to 24.1 mW with the injection current of 20 mA, and 72.4 mW to 82.4 mW with the injection current of 120 mA. In order to better illustrate the influence mechanism of the size of V-pits on the photoelectric properties of the LEDs, the schematic structures with different V-shaped pit sizes are demonstrated. The analyzing results for the LED samples show that the increase of the V-pit size is beneficial to enhance the hole injection area and injection efficiency. Thus, the light output power of the LED device is improved.