InGaN/GaN多量子阱绿光LED内量子效率及响应频率研究

Red-green-blue tricolor (RGB) white light-emitting diode (LED) has many advantages, such as good color rendering, high theory luminous efficiency, fast response frequency and so on. It is the best manufacture method of white LED for lighting and communication. However, the luminous efficiency and response rate of GaN green LED are still too low, which obviously limit the widely use of RGB white LED..On this project, we will grow GaN based green light-emitting diode by metal-organic chemical vapor deposition (MOCVD). The quantum efficiency and frequency properties are measured by temperature-dependence photoluminescence, transmission electron microscope and current- capacitor curves. We will improve the internal quantum efficiency and response frequency of the green LED by designing many novel multiple-quantum well (MQW) structures(such as strain release super-lattice, short period strain release quantum barrier, δ barrier quantum wells) and p-type GaN (such as p-InGaN conductor layer). At the same time, we will calculate the energy band structure, internal quantum efficiency of the GaN based LED by Apsys software. By combining the experimental data and the calculation results, we will clarify the physical mechanism of the internal quantum efficiency（IQE）and response frequency dependence on the epitaxial parameters of the green LED..After finishing the project, we will understand the dependence relationship of IQE and frequency of GaN based green LED. The luminous efficiency and modulation bandwidth of the green LED will be improved, which will promote the widely use of RGB white LED in high quality lighting and high speed visible light communication fields.

红绿蓝三基色(RGB)白光LED具有显色性能好、理论流明效率高、响应速率快等优点，是照明通信共用白光LED最理想的制备方法。但是其中的绿光LED量子效率和响应速度较低，大大限制了它的广泛应用。.本课题计划采用MOCVD技术生长绿光LED外延片并进行变温光致发光谱、透射电子显微镜、电流-电容曲线等测试来表征其量子效率和频率特性。设计新型量子阱结构（如应力释放超晶格量子垒、 δ 势垒量子阱等）及P型结构(如p-InGaN导电层等)并优化厚度、掺杂浓度等参数，同时提高绿光LED的量子效率和响应频率。本课题还计划采用Apsys软件数值计算GaN基LED的能带结构、自发辐射速率分布及内量子效率等参数,结合实验测试结果，确定外延结构参数影响绿光LED量子效率和响应频率的物理机制。课题完成后，将会提高绿光LED的量子效率和响应频率，推动RGB白光LED在高品质照明及高速可见光通信领域的发展。

InGaN/GaN多量子阱绿光LED存在阱垒失配度大，多量子阱晶体质量差等问题，其内量子效率很低，限制了红绿蓝(RGB)白光LED在照明通信共用领域的广泛应用。本项目针对GaN基绿光LED目前存在的问题，从外延生长角度出发，理论分析结合实验验证，改善LED的光电特性。主要研究内容和结果如下：.(a) 通过变温电流-电压曲线测试对GaN基LED的理想因子进行了细致研究，分析了LED不同偏压下理想因子的变化，揭示了LED实际理想因子比理论值偏高的物理原因。(b) 通过实验结果提取GaN LED光谱特征参数，通过理论计算分析了RGB白光LED不同光谱成分、光谱参数对其效率和显色性能的影响，为后续公司和相关科研工作者制备RGB白光LED提供理论指导。(c)采用MOCVD生长出长波长绿光LED，设计了pAlGaN导电层、GaN/InGaN/GaN 复合量子垒、以及微PN量子垒等新型外延结构，提高了绿光LED的发光效率和响应速度等特性，推动了RGB白光LED在照明通信共用领域的发展。(d)采用Ni金属球作为掩膜，制备了纳米微米复合图形化蓝宝石衬底，提高GaN基LED的晶体质量以及光提取效率。.项目执行过程中，发表SCI收录论文12篇（其中项目负责人作为第一/通信作者9篇）发表EI收录论文2篇；授权发明专利2项，实用新型专利10项，申请发明专利6项；发表IEEE收录会议论文1篇，受邀参加国内学术会议1次，国际学术会议1次。超额完成项目预期任务。