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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24.1mW;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 LEDs were grown on sapphire substrate by MOCVD. The effects of different thickness of GaN interlayers on their photoelectric properties were systematically investigated. The optical properties and surface morphology of GaN-based blue LED epitaxial wafers were characterized by using a chip tester and an atomic force microscope (AFM). When the thickness of high-temperature GaN intercalation layer increased from 60 nm to 100 nm, the size of V-shaped pit increased from 70 to 110 nm to 110 to 150 nm. When the injection current is 20 mA, the optical power of the LED chip increases from 21.9 mW to 24.1 mW. When the injection current is 120 mA, the optical power of the LED chip increases from 72.4 mW to 82.4 mW. The related physical mechanism of the V-shaped pit LED for size-controlled LED is analyzed. The results show that increasing the size of the V-shaped pit can increase the hole injection area and the injection efficiency, and improve the optical power of the LED device.