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在130~830K温度范围内,系统研究了Si(111)-3~(1/2)×3~(1/2)-Ag和Si(111)-3×1-Ag超薄膜重构表面的光学二次谐波的温度依赖性,分析了信号强度的变化和表面结构之间的关联.结果表明,对于Si(111)-3×3-Ag结构薄膜表面而言,在130K到320 K的温度范围内,表面光学二次谐波信号强度的变化中没有出现明显的跃变,反映出在这一温度范围内没有出现结构相变,与K.Sakamoto等人的光电子衍射实验结果一致.而对于Si(111)-3×1-Ag薄膜表面,二次谐波信号在200K到500K之间出现的台阶式变化可能反映了在500 K时Si(111)-3×1-Ag到Si(111)-6×1-Ag的结构相变.其结果对金属原子在半导体表面的吸附、金属超薄膜生长机理和纳米结构体系结构相变的研究具有一定的参考价值和实际意义.
In the temperature range of 130 ~ 830K, the surface reconstruction of Si (111) -3 ~ (1/2) × 3 ~ (1/2) -Ag and Si The relationship between the change of signal intensity and the surface structure was analyzed.The results showed that for the Si (111) -3 × 3-Ag structure, the surface of the film is in the range of 130K to 320K Within the temperature range, there was no obvious jump in the change of signal intensity of surface optical second harmonic, which shows that no structural phase transition occurred in this temperature range, which is consistent with the result of photoelectron diffraction experiment by K. Sakamoto et al. For the Si (111) -3 × 1-Ag thin film surface, the stepwise change of the second harmonic signal between 200K and 500K may reflect the Si (111) -3 × 1-Ag to Si 111) -6 × 1-Ag.These results have certain reference value and practical significance for the study of the adsorption of metal atoms on the semiconductor surface, the growth mechanism of the metal ultra-thin films and the phase transition of nanostructures.