采用升华法生长GaN纳米线的仿真与实验研究

发布时间：2018-05-25 10:13

  本文选题：升华法 + 氮化镓纳米线　； 参考：《南京邮电大学》2017年硕士论文

【摘要】：作为第三代优良的新型半导体材料,GaN因其宽禁带、抗辐射、化学性质稳定等特性广泛应用于光电元器件的研制。近年来,随着GaN材料特性的深入研究,研究人员实验中发现了不仅可以生长GaN薄膜,还可以生长GaN一维纳米材料,因此受到了国内外的广泛关注。本课题采用自主设计的升华法生长系统,主要包括两个部分,即基于计算流体力学的数值模拟和实验制备GaN纳米线的研究。为了缩短升华法生长系统的设计周期和有效改善腔体结构设计,主要从生长温度、衬底相对基座的高度和基座相对反应腔体的高度等方面进行了二维模型的数值模拟,通过模拟分析衬底表面Ga、NH3的摩尔浓度分布和GaN生长速率等来研究对生长GaN纳米线的影响。通过计算模拟分析得出生长温度为1050℃、衬底相对高度为6mm和基座相对高度为25mm的生长条件下,模拟生长GaN纳米线的生长均匀性更好。另外在已经优化的生长条件下又探讨了加入不同流量的载气N2后数值模拟分析反应腔体内部的流场分布情况。采用升华法生长技术,从NH3流量、生长时间、催化剂和缓冲层等方面进行实验室制备GaN纳米线,通过扫描电子显微镜(SEM)对实验制备的GaN纳米线进行形貌表征分析。通过对比样品的SEM图的形貌表征,发现石墨烯插层、NH3流量,反应时间、有无催化剂和GaN缓冲层对GaN纳米线的形貌有较大影响。在适当的氨气流量、在无催化剂时,石墨烯上可以生长GaN纳米线,纳米线直径约80nm,长度约10μm。在引入缓冲层和催化剂后,GaN纳米线呈现趋向竖直排列的模式。研究结果表明,石墨烯、缓冲层和催化剂对GaN纳米结构的成核提供了基础,在一定条件下可以生长出优化的纳米线结构。通过数值模拟和实验制备,对改善生长系统腔体结构和优化生长工艺提供理论依据,对实验生长GaN纳米阵列具有一定的指导意义。
[Abstract]:As a new kind of semiconductor material of the third generation, gan is widely used in the development of optoelectronic components because of its wide band gap, radiation resistance and chemical stability. In recent years, with the in-depth study of the properties of GaN materials, researchers have found that not only GaN thin films can be grown, but also one-dimensional GaN nanomaterials can be grown, so it has attracted wide attention at home and abroad. The self-designed sublimation growth system consists of two parts: numerical simulation based on computational fluid dynamics (CFD) and experimental preparation of GaN nanowires. In order to shorten the design period of sublimation growth system and improve the design of cavity structure effectively, the numerical simulation of two-dimensional model is carried out mainly from the aspects of growth temperature, the height of substrate relative to base and the height of base relative to reactive cavity, etc. The influence of GaN nanowires on the growth of GaN nanowires was studied by simulating the molar concentration distribution of GaH3 and the growth rate of GaN on the substrate surface. The simulated growth temperature is 1050 鈩，

本文编号：1933053