Ag/Si（111）超薄膜光学二次谐波强度变化与结构相变研究

在130-830K温度范围内,系统研究了Si（111）-√3×√3-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...

A STUDY OF SECOND-HARMONIC GENERATION FROM Ag/Si(111) AND PHASE TRANSITION

The temperature dependence of optical surface second-harmonic generation signal from Si（111）-3^1/2×3^1/2-Ag and Si（111）-3×1-Ag surfaces were studied with the temperature ranging from 130 K to 830 K.The relationship between the signal and surface structure has been discussed.In our experiments,no remarkable signal change reflecting phase transition of Si（111）-3^1/2×3^1/2-Ag has been observed from 130 K to 320 K,consistent with the photoelectron diffraction results of K.Sakamoto et al.For the Si（111）-3×1-Ag structure,the second-harmonic signals show step-changes at about 200 K to 500 K,which may reflect a phase transition from Si（111）-3 × 1-Ag to Si（111）-6 × 1-Ag at about 500 K.The result has practical significance in the study of metal atom adsorption on the semiconductor surface,the growth mechanism of metal ultrathin films and the phase transition of nanostructures.