碳量子点/ZnO纳米复合结构的制备、物性调控及其光发射器件研究

Carbon-based materials have a variety of morphological structures and excellent photoelectric properties; leading to significant applications in optoelectronic and photovoltaic devices. Short wavelength optoelectronic devices, a subject of important research in the field of optoelectronic information, have broad application prospects in light, display, information storage, biology environmental protection. This proposal aims to increase the luminescence efficiency of ZnO-based heterojunction light-emitting diodes (LEDs) by introducing carbon nanodot/ZnO nano-composite structure. A core-shell nanorod arrays are prepared by green chemical synthesis, pulsed laser deposition and atomic layer deposition, and their structural and optoelectronic properties will be studied in detail; based on finite-difference time-domain simulation, carbon nanodot localized surface plasmons (LSP) will be incorporated into the core-shell nanorod arrays by physical deposition or chemical synthesis methods to forming a composite structural system; the effect of resonant coupling among ZnO exciton, photon, polariton and LSP on light-emitting efficiency will be investigated; the carbon nanodot/ZnO nano-composite structures serve as active layer to construct heterojunction LEDs, and reveal the dynamic processes about relevant carrier injection, transportation, recombination and relaxation; the physical mechanism of improved ZnO radiative recombination will be also studied detailedly, adjusting the emission wavelength of nano-composite structure, and obtained the increasing efficiency of ZnO-based LEDs, and realizing high-efficiency and stable white LEDs.

碳基材料以其丰富的形态结构和优异的光电性质，在光电子与光伏器件的应用中具有重要意义；短波长光电子器件在照明显示、信息存储、生物环保等领域有广阔的应用前景，是当前光电子信息领域重要的研究方向。本项目针对ZnO基异质结光发射器件（LED）效率低的问题，拟开展碳量子点/ZnO纳米复合结构体系LED的研究工作。利用绿色化学合成、脉冲激光沉积、原子层沉积等方法制备核壳纳米柱阵列，确定光电性质与结构参数的关联性；借助时域有限差分模拟，采用物理沉积或化学方法将碳量子点局域表面等离激元（LSP）引入上述结构中，形成复合结构体系；探究ZnO激子、光子、极化子与LSP的耦合机制及对发光效率的影响；以复合体系为有源层构造异质结器件，揭示载流子注入、输运、复合、弛豫等动力学过程；研究ZnO辐射复合改善的物理机制，调节复合结构的发射波长，获得ZnO基LED效率提升的同时，实现高效稳定白色LED。

短波长光电子器件在半导体照明、平板显示、高密度信息存储、微电子加工等领域有巨大应用潜力。ZnO材料具有直接宽带隙，高激子束缚能和光学增益系数等优势，被认为是继GaN之后第三代半导体的研究热点和前沿领域。本项目围绕ZnO材料构筑异质结器件，从材料选择，结构设计，器件性能调控以多功能化等方面开展了系列研究工作。取得的主要创新性结果如下：（1）通过改变ZnO纳米结构生长条件，揭示了其生长动力学原理及过程，获得了ZnO量子点基异质结LED原型器件。（2）构建了碳量子点修饰的ZnO量子点异质结LED器件，发现了碳量子点表面等离激元效应，揭示了ZnO紫外发光增强的机理，优化了器件性能。（3）构筑了石墨烯嵌入的ZnO纳米柱/p-GaN异质结器件，通过插入石墨烯片层，开发了一种新型碳基表面等离激元修饰的ZnO三维纳米复合结构，有效提升了器件紫外发光效率。（4）利用新型二维材料和钙钛矿材料，开展了发光动力学及其阻变随机存储器研究，为进一步构造ZnO基异质结紫外发光器件及应用提供借鉴。本项目研究结果对于理解半导体发光材料与器件领域相关物理问题提供了一些科学依据和技术基础，并为开发基于其他半导体发光材料的光电子器件提供有效参考。