InGaNP薄膜带隙演化及其退火特性的物理机制研究

Recently, the quaternary alloys InGaNP have attracted much attention due to their unusual properties and possible application in red light emitting diode (LED). However, because of the poor investigation, the physical and chemical properties of InGaNP are not clear. Their utility is limitied by the low luminescence efficiency. Due to the above factors, it is hard to improve the performance of the red LED. In order to solve the above problems, we intend to investigate InGaNP films. Firstly, we plan to investigate the compositional dependence of the band gap energy and obtain the exact values of the parameters in the band-anticrossing (BAC) model for InGaNP. Secondly, the pressure dependence of the band gap energy will be studied in order to understand the N-Γ coupling interaction and the N-X coupling interacton. After two coupling interactions are clear, a model will be developed to describe the pressure dependence of the band gap energy. Thirdly, 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) and transmission electron microscope (TEM). At last, the effect of annealing on the parameters in the band anticrosing (BAC) model will be considered and the modified BAC 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 InGaNP 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 red LED.

InGaNP合金是一种制备高性能红光LED的新兴材料。目前此种合金的研究成果十分匮乏，材料的理化特性尚未完全清楚，这严重阻碍了该种材料在照明领域中的应用。鉴于此，该项目以InGaNP薄膜带隙为研究对象，拟通过研究InGaNP合金带隙的组分依赖特性，进一步揭示其能带演化的物理机制，精确band-anticrossing（BAC）模型参数；通过研究带隙的压强依赖特性，揭示N能级与主材料InGaP合金导带底（Γ导带底和X导带底）间的相互作用机理，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，揭示引起InGaNP合金带隙蓝移的物理机制；在此基础上，借助BAC模型，定量分析带隙蓝移对BAC模型参数的影响。该课题研究有利于深化对InGaNP合金能带的认识，改善InGaNP材料质量，减小带隙蓝移对器件的不利影响，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InGaNP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）课题组研究了典型的三元稀氮化物、四元稀氮化物和五元稀氮化物合金带隙的组分依赖特性，分析了稀氮化物合金带隙演化的物理机制，建立物理模型定量描述了三元稀氮化物、四元稀氮化物和五元稀氮化物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）研究了退火后四元稀氮化物合金带隙蓝移现象，揭示了带隙蓝移的物理机制，建立物理模型定量描述了带隙蓝移量。（4）课题组开展了稀铋化物合金带隙、稀氧化物合金带隙、四元氧化物合金带隙、整个组分区域内ZnSeO合金带隙等方面的研究，分析了上述合金带隙演化的物理机制，建立物理模型定量描述了合金带隙的组分依赖特性。（5）课题组研究了富Ga组分区域InGaN合金的Mg杂质电离能和整个组分区域内AlGaN合金的Mg杂质电离能，明确了影响Mg杂质电离能的各种因素，建立物理模型定量描述了Mg杂质电离能。该课题研究有利于深化对稀氮化物及其相关合金能带的认识，改善稀氮化物材料质量和发光特性，减小带隙蓝移对器件的不利影响，提升器件性能，对半导体产业的发展具有重要意义。