Enhanced near-UV electroluminescence from p-GaN/i-Al2O3/n-ZnO heterojunction LEDs by optimizing the insulator thickness and introducing surface plasmons of Ag nanowires
Enhanced near-UV electroluminescence from p-GaN/i-Al2O3/n-ZnO heterojunction LEDs by optimizing the insulator thickness and introducing surface plasmons of Ag nanowires
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DOI：
10.1039/c7tc00419b
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发表时间：
2017-03
影响因子：
6.4
通讯作者：
Liu Yang;Weizhen Liu;Haiyang Xu;Jiangang Ma;Ceng Zhang;Chunyang Liu;Zhongqiang Wang;Yichun Liu
中科院分区：
文献类型：
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作者：
Liu Yang;Weizhen Liu;Haiyang Xu;Jiangang Ma;Ceng Zhang;Chunyang Liu;Zhongqiang Wang;Yichun Liu
采用原子层沉积技术制备了不同Al 2 O3厚度的p-GaN/i-Al 2 O3/n-ZnO（PIN）异质结LED。通过将i-Al 2 O 3层厚度优化为约12 nm，在n-ZnO有源层中同时实现了有效的电子积累和空穴注入，从而大大提高了该PIN型LED的近紫外电致发光强度。此外，通过引入Ag纳米线，其表面等离子体激元（SP）共振能量更接近于ZnO的紫外发射能量，到LED结构中，电致发光强度进一步提高了2.8倍。时间分辨和温度依赖的光谱分析表明，无论是自发辐射率和内量子效率的ZnO有源层的ZnO激子和银纳米线SP之间的共振耦合的结果增加，这引起了观察到的近紫外电致发光增强。
p-GaN/i-Al2O3/n-ZnO (PIN) heterojunction LEDs with different dielectric Al2O3 thicknesses were fabricated via an atomic layer deposition technique. By optimizing the i-Al2O3 layer thickness to be ∼12 nm, the effective electron accumulation and hole injection are simultaneously achieved in the n-ZnO active layer, resulting in a greatly improved near-UV electroluminescence intensity of this PIN type LED. Moreover, by introducing Ag nanowires, whose surface plasmon (SP) resonant energy is closer to the ZnO UV emission energy, into the LED structure, the electroluminescence intensity was further increased ∼2.8 times. Time-resolved and temperature-dependent spectroscopy analyses reveal that both the spontaneous radiation rate and internal quantum efficiency of the ZnO active layer are increased as a result of resonant couplings between ZnO excitons and Ag nanowire SPs, which gives rise to the observed near-UV electroluminescence enhancement.