Coaxial InxGa1-xN/GaN Multiple Quantum Well Nanowire Arrays on Si(111) Substrate for High-Performance Light-Emitting Diodes
Coaxial InxGa1-xN/GaN Multiple Quantum Well Nanowire Arrays on Si(111) Substrate for High-Performance Light-Emitting Diodes
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DOI：
10.1021/nl400906r
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发表时间：
2013-08-01
期刊：
影响因子：
10.8
通讯作者：
Lee, Cheul-Ro
中科院分区：
文献类型：
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作者：
Ra, Yong-Ho;Navamathavan, R.;Lee, Cheul-Ro
报道了用于无偏振高内量子效率发光二极管(LED)的高质量非极(m-面)和半极(r-面)多量子阱(MQW)纳米线的生长。采用脉冲流动金属-有机化学气相沉积(MOCVD)技术，在Si(111)衬底上，在六方c轴n-GaN NW的{1-100}侧壁上同轴生长了高取向、均匀的InxGa1-xN/GaN多量子阱薄膜。光致发光(PL)测量表明，具有不同对(2-20)的MQW结构的波长和强度非常稳定，并且在369-600 nm范围内具有成分依赖的发射。InxGa1-xN/GaN多量子阱纳米管的阴极发光光谱以369和440 nm的带边发射为主，具有相对均匀的平行排列分布。同轴InxGa1-xN/GaN多量子阱纳米晶沿<；0001>；和<；2-1-10>；区轴方向的高分辨透射电子显微镜(HR-TEM)研究表明，生长的纳米晶是均匀的，有六个非极性的m平面面，没有任何位错和层错。P-GaN/InxGa1-xN/GaN MQW/n-GaN NW同轴LED具有电流整流特性，正向偏置电压为2.65V。功率的线性提高可以归因于InxGa1-xN/GaN MQW有源区压电场的消除。与薄膜LED相比，同轴NW LED具有更好的性能。总之，利用脉冲MOCVD技术获得低缺陷、无应变的m平面同轴NW的可行性可以用来实现高功率LED而不会出现效率下降。这种同轴波导波是一种可行的高比表面积多量子阱结构，可以用来提高LED的效率。
We report the growth of high-quality nonpolar (m-plane) and semipolar (r-plane) multiple quantum well (MQW) nanowires (NWs) for high internal quantum efficiency light emitting diodes (LEDs) without polarization. Highly aligned and uniform InxGa1-xN/GaN MQW layers are grown coaxially on the {1-100} sidewalls of hexagonal c-axis n-GaN NWs on Si(111) substrates by a pulsed flow metal-organic chemical vapor deposition (MOCVD) technique. The photoluminescence (PL) measurements reveal that the wavelength and intensity of an MQW structure with various pairs (2-20) are very stable and possess composition-dependent emission ranging from 369 to 600 nm. The cathodoluminescence (CL) spectrum of individual InxGa1-xN/GaN MQW NW is dominated by band-edge emission at 369 and 440 nm with a relatively homogeneous profile of parallel alignment. High-resolution transmission electron microscopy (HR-TEM) studies of coaxial InxGa1-xN/GaN MQW NWS measured along the < 0001 > and < 2-1-10 > zone axes reveal that the grown NWs are uniform with six nonpolar m-plane facets without any dislocations and stacking faults. The p-GaN/InxGa1-xN/GaN MQW/n-GaN NW coaxial LEDs show a current rectification with a sharp onset voltage at 2.65 V in the forward bias. The linear enhancement of power output could be attributed to the elimination of piezoelectric fields in the InxGa1-xN/GaN MQW active region. The superior performance of coaxial NW LEDs is observed in comparison with that of thin film LEDs. Overall, the feasibility of obtaining low defect and strain free m-plane coaxial NWs using pulsed MOCVD can be utilized for the realization of high-power LEDs without an efficiency droop. These kinds of coaxial NWs are viable high surface area MQW structures which can be used to enhance the efficiency of LEDs.