Si(110)和Si(111)衬底上制备InGaN/GaN蓝光发光二极管

In Ga N/Ga N blue light emitting diodes grown on Si(110)and Si(111) substrates

分别在Si(110)和Si(111)衬底上制备了In Ga N/Ga N多量子阱结构蓝光发光二极管(LED)器件.利用高分辨X射线衍射、原子力显微镜、室温拉曼光谱和变温光致发光谱对生长的LED结构进行了结构表征.结果表明,相对于Si(111)上生长LED样品,Si(110)上生长的LED结构晶体质量较好,样品中存在较小的张应力,具有较高的内量子效率.对制备的LED芯片进行光电特性分析测试表明,两种衬底上制备的LED芯片等效串联电阻相差不大,在大电流注入下内量子效率下降较小;但是,相比于Si(111)上制备LED芯片,Si(110)上LED芯片具有较小的开启电压和更优异的发光特性.对LED器件电致发光(EL)发光峰随驱动电流的变化研究发现,由于Si(110)衬底上LED结构中阱层和垒层存在较小的应力/应变而在器件中产生较弱的量子限制斯塔克效应,致使Si(110)上LED芯片EL发光峰随驱动电流的蓝移量更小.

In this paper, InGaN/GaN multiple quantum-well blue light emitting diodes （LEDs） are successfully grown on Si（110） and Si（111） substrates. The micro-structural properties of the LEDs are characterized by means of high- resolution X-ray diffraction, atomic force microscopy, Raman spectra, and temperature dependent photoluminescence measurements. The results show that the sample on Si（110） substrate exhibits the high crystal quality, weak tensile strain, and large internal quantum efficiency. The optoelectronic properties of the LED devices are also investigated. The I-V curves indicate that the LED devices fabricated on Si（110） and Si（111） substrates have similar series resistances and low reverse leakage currents, but the LED devices fabricated on Si（110） substrate possess lower turn-on voltages. The relationship between light output intensity and injection current suggests that the LED device fabricated on Si（110） substrate has a strong light output efficiency. The study on the variation of spectral peak energy with injection current of the LED device reveals that LED device on Si（110） substrate presents a smaller spectral shift range when increasing the injection current. And the smaller spectral shift range reflects the weak quantum-confined Stark effect in the device, which can he attributed to the high crystal quality and weak strain between well layer and barrier film in the LED sample grown on Si（110）.