稀氮化物InGaNAsSb合金带隙演化规律及其退火特性的物理机制研究

Recently, the quinary alloys InGaNAsSb have attracted much attention due to their unusual properties and possible application in vertical-cavity surface-emitting laser (VCSEL). However, because of the poor investigation, the physical and chemical properties of InGaNAsSb are still not known fully. Their utility is limitied by the poor quality and luminescence efficiency. In order to solve the above problems, we intend to investigate InGaNAsSb films. Firstly, We plan to investigate the composition dependence of the band gap energy in a larger composition range and develop a model to describe it. Secondly, a model will be developed to describe the reduction of the temperature sensitiveness of the band gap energy depending on the localized effect of the N level. Thirdly, the pressure dependence of the band gap energy will be studied in order to understand the coupling interaction between impurity level and the band (the conduction band and the valence band) of the host material. After the above coupling interactions are clear, a model will be developed to describe the pressure dependence of the band gap energy. Fourthly, we intend to study the blueshift of the band gap energy after annealing. The physical mechanism for the blueshift of the band gap energy will be analyzed by using photoluminescence (PL), X-ray diffraction (XRD), Raman spectra, X-ray photonelectron spectroscopy (XPS), Fourier transform infrared spectroscopy（FTIR）, and transmission electron microscope (TEM). At last, the effect of annealing on the parameters in the double band-anticrossing (DBAC) model will be considered and the modified DBAC model will be used to describe the blueshift of the band gap energy after annealing. The investigation is very helpful to improve the crystal quality and luminescence efficiency of InGaNAsSb alloys. It is also helpful to understand the physical mechanism of the blueshift of the band gap energy caused by annealing. Based on the above factors, it can be seen that the significance of the investigation is very remarkable for improving the performance of the VCSEL.

InGaNAsSb合金是一种制备垂直腔面发射激光器的新兴材料。目前此种合金的理化特性尚未完全清楚，这严重阻碍了该种材料在器件领域中的应用。鉴于此，该项目以InGaNAsSb薄膜带隙为研究对象，拟通过研究InGaNAsSb合金带隙的组分依赖特性和温度依赖特性，进一步揭示其能带演化的物理机制，建立物理模型量化带隙与组分、带隙温度敏感性降低与N能级局域化效应间的关系；通过研究该合金带隙的压强依赖特性，揭示N能级与主材料导带底、Sb能级与主材料价带顶间相互作用的物理机理，建立物理模型量化带隙与压强的关系；对于退火引起的带隙蓝移，计划利用多种实验手段进行探究，揭示合金带隙蓝移的物理机制；在此基础上，借助双band anticrossing模型，定量分析带隙蓝移对该模型参数的影响。该研究有利于深化对InGaNAsSb合金能带的认识，改善材料质量和发光特性，提升器件性能，对半导体产业的发展具有重要意义。

课题组在遵循原有研究计划的同时，适当扩展了研究领域，将研究对象从单一的稀氮化物InGaNSbAs合金带隙扩展到了整个稀氮化物及其相关领域。主要研究内容、重要结果及其关键数据如下：（1）课题组研究了含氮组分超出稀氮化物组分区域的氮化物合金带隙的组分依赖特性，分析了其带隙演化的物理机制，建立物理模型定量描述了其合金带隙的组分依赖特性。（2）研究了稀氮化物合金带隙的压强依赖特性，分析了带隙随压强变化的物理机制，建立物理模型定量描述了带隙的压强依赖特性。（3）研究了局域化杂质能级使带隙温度敏感性降低现象，建立物理模型定量描述带隙温度敏感性的降低。（4）课题组利用第一性原理计算开展了Ⅲ-Bi-Ⅴ合金带隙和晶格常数、典型的Zn-O-Ⅵ三元合金的带隙和晶格常数、富Ge组分范围内GeSn的晶格常数和带隙、整个组分区域内单层二维金属硫化物合金的结构、带隙和磁学特性等方面的研究，分析了上述合金带隙演化的物理机制，建物理模型定量描述了合金带隙的组分依赖特性。（5）课题组研究了四元稀氧化物CdZnOTe合金带隙和整个组分区域ZnSeO合金带隙，分析了其带隙演化的物理机制，建立物理模型定量描述了其带隙的组分依赖特性。该课题研究有利于深化对Ⅲ-N-Ⅴ合金及其相关合金能带的认识，改善Ⅲ-N-Ⅴ合金及其相关合金材料质量和发光特性，提升器件的工作稳定性，对半导体产业的发展具有重要意义。