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用光致发光谱及高分辨率的X射线双晶衍射对 MBE GaAs/Si异质结材料进行研究,发现GaAs外延层和Si衬底存在一定的晶向偏离,整个GaAs外延层呈现双轴张应力,这是GaAs和Si的晶格失配导致的双轴压应力和热膨胀系数失配导致的双轴张应力的总结果.本文根据一定的物理假设,推导出GaAs外延层中的平均应力,表明应力与材料所处的温度相关.据此,本文进一步用光致发光谱测量了25K至 260K温度范围内的应力,发现应力随温度的增大而下降,与理论公式反映的规律吻合.
MBE GaAs / Si heterojunction materials have been studied by photoluminescence spectroscopy and high-resolution X-ray double crystal diffraction. It is found that the GaAs epitaxial layer and the Si substrate have a certain crystal orientation deviation, and the entire GaAs epitaxial layer exhibits biaxial Stress, which is the result of the biaxial tensile stress caused by the lattice mismatch between GaAs and Si and the coefficient of thermal expansion mismatch.Based on certain physical assumptions, the average stress in the GaAs epitaxial layer is deduced, Which indicates that the stress is related to the temperature at which the material is located.Therefore, the stress in the temperature range of 25K to 260K was further measured by photoluminescence spectroscopy, and it was found that the stress decreased with the increase of temperature, which was in good agreement with the theoretical formula.