高性能氧化锌基发光器件研究

	高性能氧化锌基发光器件研究
	刘兴宇
学位类型	博士
导师	单崇新
	2014-07
学位授予单位	中国科学院大学
学位专业	凝聚态物理
摘要	氧化锌（ZnO）是一种具有60 meV 激子结合能的直接宽禁带半导体材料，其带边发射为3.37 eV，因为其室温下激子可以稳定存在，并且激子相关的发光效率在理论上比普通的电子空穴等离子效率高，多年来一直作为一种新型高效率发光材料而被广泛关注，而氧化锌的纳米结构：纳米线、量子点、纳米管等易于合成，其相关的发光器件也被大量研究，尤其是纳米线基发光器件取得了大量的新进展。但是ZnO纳米线发光器件距离应用还面临着诸多问题，本论文基于这些问题展开了研究，取得的主要结果如下：1. P-n 结是实现高效氧化锌发光器件的最优选择，但是长久以来，困扰p-n结器件的最大问题就是同时具备高空穴浓度，高迁移率的p型氧化锌一直没有研制成功。基于此问题，采用金属-绝缘层-半导体（MOS）结构，实现了基于高结晶质量的纳米线阵列的发光二极管，是氧化锌基发光器件的最大输出功率之一。 2. 高结晶质量的氧化锌材料是实现高效氧化锌发光器件的基础，但对于氧化锌薄膜材料来说，由于与传统衬底（蓝宝石，硅）的晶格失配较大，很难形成高质量薄膜，而氧化锌单晶衬底的造价过于昂贵，无法在应用中广泛使用。这些都为高结晶质量的氧化锌材料的制备造成了困难。基于此问题，我们通过优化MOCVD的生长工艺，制备了高结晶质量的氧化锌单晶纳米线阵列，并在高质量的氧化锌纳米线的基础上制备了Au/MgO/ZnO的异质结，实现基于该高质量氧化锌纳米线的电泵浦随机激光。3. 利用MOCVD制备了垂直排列的ZnO纳米线，该纳米线显示出良好的结晶和光学性质，以该纳米纤为工作物质，构建了p-Zn0.68Mg0.32O/n-ZnO异质结构，正向偏压下p-Zn0.68Mg0.32O层中的空穴被注入到ZnO纳米线中并与纳米线中的电子复合发光，实现了纯近带边ZnO LEDs，而常见的缺陷发光则几乎被完全抑制。且该器件可持续工作时间27小时，是目前已报道的氧化锌基发光器件的最长寿命，显示了良好的可靠性。
其他摘要	ZnO has a direct wide bandgap of 3.37 eV and a large exciton binding energy of 60 meV, which means that the excitons in ZnO can exist at room temperature. It is accepted that the luminescence efficiency of exciton-related emission is high compared with that of electron-hole recombination. Thus, much attention has been attracted in recent years. Another character of ZnO lies in its rich nanostructures, and self-assembled nanostructures usually have relatively high crystalline and optical quality. If ZnO nanostructures can be employed as the active layer of a light-emitting device (LED), the performance of such devices may be improved significantly. In this thesis, we aim at improving the performance of ZnO-based LEDs, and the following results have been obtained: 1. P-n junction is an ideal structure for efficient LEDs, but the p-type doping of ZnO is still a challenging issue. Under such circumstance, holes generated via an impact ionization process have been employed, and Au/MgO/ZnO structures have been fabricated by employing ZnO nanocolumns as an active layer. which is amongst the highest output power ever reported in ZnO-based LEDs. 2. High quality ZnO is essential for high-performance LEDs, but it is difficult to prepared high quality ZnO films since the large lattice mismatch between the common employed sapphire substrate and the ZnO films. In this part, well-aligned ZnO nanowires with high crystalline and optical qualities have been prepared, and electrically pumped random lasing has been obtained from the ZnO nanowire based devices. 3. By employing high crystalline and optical quality ZnO nanowires as the active layer, a p-Zn0.68Mg0.32O/n-ZnO heterostructures have been prepared, and the holes in the p-Zn0.68Mg0.32O layer will be injected into the ZnO nanowires, and recombine with electrons in the nanowires under forward bias. In this way, pure ultraviolet emissions have been obtained from the ZnO LEDs, while the deep-level related emission that is frequently observed in ZnO-based LEDs is almost totally absent. The LEDs can work continuously for 27 hours, indicating their good reliability.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41441
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	刘兴宇. 高性能氧化锌基发光器件研究[D]. 中国科学院大学,2014.

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