毫秒激光致砷化镓材料损伤研究

发布时间：2018-06-19 13:49

本文选题：激光损伤 + 毫秒激光　；参考：《南京理工大学》2017年硕士论文

【摘要】：近些年来,砷化镓材料在航天科技以及国防军事领域有着越来越多的应用。以其为原料所制造的太阳能电池在转化效率方面有着其他材料无法比拟的优势。而激光对材料的损伤一直以来都是科研的热点问题。目前,关于毫秒激光致砷化镓材料损伤方面的研究并不是很多,相关的损伤机理仍然有待于探索。为了探究1064nm毫秒激光损伤砷化镓材料的机理,本文通过实验以及建模的方法,对材料受辐照过程中热及热应力在损伤中的作用进行了分析。基于三维热传导方程建立了 1064nm毫秒激光辐照砷化镓材料时材料的温度场模型。模型结果显示,对于1064nm,1ms的激光,砷化镓材料的损伤阈值为61.5J/cm2。通过模型还得到了材料在不同能量密度激光辐照时,熔融,重凝固等相变过程的信息,以及不同能量密度时材料的熔融阈值,熔融半径,熔融深度。同时搭建实验平台,采用红外测温仪对受激光辐照时材料光斑中心点的温度进行实时的测量。实验所得到的温升曲线和模型所得到的结果相吻合,验证了模型的准确性。基于温度场模型,再考虑砷化镓的晶体结构,建立了毫秒激光辐照砷化镓材料的热应力场模型,并计算了砷化镓材料12个滑移系的分切应力在材料表面及体内的分布。模型结果显示,材料受激光辐照后产生裂纹是由于砷化镓晶体内滑移系分切应力超过临界分切应力而导致的滑移产生的。材料的滑移将在热熔损伤之前出现,其将最先在材料受辐照面光斑中心内部的区域产生。滑移的发生将为材料之后进一步的脆性断裂提供起始点。计算结果显示,材料受激光辐照后所出现的裂纹最有可能出现在光斑中心及边界附近,这与我们在实验中所得到的结果相吻合。本文的研究成果对于进一步的研究毫秒激光作用物质的机理提供参考。
[Abstract]:In recent years, gallium arsenide materials have been used more and more in space science and technology as well as defense and military fields. The solar cells made from the solar cells have more advantages than other materials in conversion efficiency. Laser damage to materials has always been a hot issue in scientific research. At present, there are not many researches on the damage of GaAs materials induced by millisecond laser, and the related damage mechanism remains to be explored. In order to explore the mechanism of 1064nm millisecond laser damage of GaAs materials, the effect of thermal and thermal stress on the damage of materials during irradiation was analyzed by means of experiments and modeling. The temperature field model of GaAs material irradiated by 1064nm millisecond laser is established based on three dimensional heat conduction equation. The model results show that the damage threshold of gallium arsenide is 61.5 J / cm ~ 2 for 1064 nm ~ (-1) Ms laser. The information of phase transformation such as melting and resolidification of materials irradiated by laser with different energy densities, as well as the melting threshold, melting radius and melting depth of the materials with different energy density were also obtained by the model. At the same time, an experimental platform was set up to measure the temperature of the spot center of the material under laser irradiation with infrared thermometer in real time. The temperature rise curve obtained by the experiment coincides with the results obtained by the model, which verifies the accuracy of the model. Based on the temperature field model and considering the crystal structure of gallium arsenide, the thermal stress field model of GaAs material irradiated by millisecond laser is established, and the distribution of shear stress in the surface and body of 12 slip systems of gallium arsenide material is calculated. The model results show that the crack caused by laser irradiation is due to the slip caused by the slip system shear stress exceeding the critical shear stress in GaAs crystal. The slippage of the material will occur before the hot melt damage, and it will occur first in the region inside the center of the spot on the irradiated surface of the material. The occurrence of slip will provide the starting point for further brittle fracture after the material. The calculated results show that the cracks after laser irradiation are most likely to occur near the center and boundary of the spot, which is in agreement with our experimental results. The results of this paper provide a reference for further study of the mechanism of millisecond laser acting on matter.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN304.23;TN249

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