GaAs衬底上分子束外延生长InGaAsN薄膜及其机理研究

发布时间：2018-04-29 04:42

本文选题：GaAs + InGaAsN　；参考：《华南理工大学》2015年硕士论文

【摘要】：稀氮化合物In Ga As N具有显著的能带弯曲特性,其在长波长激光器件、近红外探测器和薄膜太阳电池上有着十分广阔的应用前景,因此在Ga As衬底上外延生长In Ga As N薄膜的研究一直很受关注。与其他III-V族半导体化合物相比,In Ga As N最为显著的特点是,它与Ga As衬底晶格匹配的同时,通过调节N和In的组分即可在较大范围内调整自身的带隙宽度。然而,In Ga As N/Ga As体系的外延生长过程需要控制的变量有很多,In Ga As N薄膜生长机理非常复杂。在生长工艺方面,尤其是关于生长温度、束流比、生长速率等因素上对薄膜生长的影响分析相对不足。此外,生长过程中原子吸附和原子迁移方面的研究也是较为匮乏,导致相关的机理研究不够完备和系统化。本文运用MBE方法,在Ga As衬底上生长了In Ga As N薄膜。以晶体结构、薄膜形貌、并入成分或电学性能参数这四个方面作为评判薄膜生长质量的标准,并详细分析和研究了衬底外延晶面、As/III束流比、生长温度、射频N源工作参数、生长速率这五个因素对In Ga As N薄膜生长的影响,其中重点讨论了In原子的并入和表面迁移特性。从实验结果逐步得出合理的In Ga As N/Ga As体系生长工艺参数。此外,我们运用计算模拟方法,对N原子的吸附、脱附、扩散迁移、与其他原子的相互作用等一系列行为特性进行了深入的讨论,并展示与实验相吻合的结果,为研究In Ga As N薄膜生长机理提供指导。此外,我们通过密度泛函理论(DFT)计算对In Ga As N的能带结构和电子分布进行了研究,继而解释了In Ga As N薄膜的载流子迁移率较低的问题。
[Abstract]:The dilute nitrogen compound In Ga As N has significant band bending characteristics. It has a very broad application prospect in the long wavelength laser devices, near infrared detectors and thin film solar cells. Therefore, the epitaxial growth of In Ga As N thin film on the Ga As substrate has always been paid much attention. The remarkable feature is that, while it is matched with the Ga As substrate lattice, the band gap width can be adjusted in a larger range by adjusting the components of N and In. However, there are many variables to be controlled by the epitaxial growth process of the In Ga As N/Ga As system, and In Ga As thin film growth mechanism is very complex. In the growth process, especially in respect to the growth process, The influence of growth temperature, beam ratio and growth rate on the growth of thin film is relatively insufficient. In addition, the study of atomic adsorption and atomic migration is also deficient in the growth process. The related mechanism is not complete and systematic. In this paper, the In Ga As N film was grown on the Ga As substrate by the MBE method. The four aspects of structure, film morphology, incorporation of composition or electrical properties are considered as the criteria for evaluating the growth quality of thin films, and the effects of the five factors on the growth of In Ga As N thin film are analyzed and studied in detail, including the epitaxial surface of the substrate, the As/III beam flow ratio, the growth temperature, the working parameters of the RF N source, and the growth rate. The focus is on the In atom. The growth process parameters of the In Ga As N/Ga As system are gradually obtained from the experimental results. In addition, a series of behavior characteristics, such as the adsorption, desorption, diffusion and migration of N atoms, and the interaction with other atoms are discussed by the calculation simulation method. In addition, we have calculated the band structure and electron distribution of In Ga As N by density functional theory (DFT), and then explained the low carrier mobility of In Ga As As N As N.

【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2

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