Si(111)7×7表面Na沉积过程的光学二次谐波法研究  

Optical Second-Harmonic Generation Study ofNa Adsorption on Si(111) 7×7 Surface

作　　者：孙丽娜[1] 邓冬梅[1] 白丽华[1] 王春涛[1] 曹世勋[1] 张金仓[1] 

机构地区：[1]上海大学物理系,上海200444

出　　处：《真空科学与技术学报》2012年第9期845-849,共5页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(批准号:10804067;60908006)

摘　　要：用原位光学二次谐波方法监测了室温时Na在Si(111)7×7表面沉积过程中的信号变化。室温下Na沉积量小于饱和单层时信号变化比较复杂,随Na沉积量的变化依次出现三个特征峰。覆盖度约0.45 ML时出现较弱的峰A,其产生可能与碱金属诱导的占据态F和没有被占据的态A间的跃迁所引起的共振增强有关;随后在约0.9 ML的覆盖度下出现峰B并在沉积量大于饱和单层后信号快速增大,形成陡峭的峰C。相测量表明峰B与峰C信号之间存在明显的相位差,说明两者的起源有不同之处。峰C的出现与等离激元的激发密切相关。在峰B所处的覆盖度下,二维及二维-三维过渡结构的存在可能产生两种以上不同起源的二次谐波信号,其相干叠加促成了峰B的出现。We addressed the adsorption of Na on Si（111） 7×7 restructured surface by in-situ second-harmonic generation technique at room temperature.Three distinctive characteristic peaks,Peak A at a Na coverage of 0.45 monolayer（ML）;Peak B at 0.9 ML,and spike-like Peak C,at a coverage over the saturated monolayer,were observed.Peak A,fairly weak,may possibly correlate with a resonance enhancement due to a transition between the alkali-induced occupied states F and unoccupied states A,while Peak C may originate from the surface plasmon resonance.The phase measurement data show a significant difference between Peak B and Peak C,indicating different origins of the two peaks.One possible reason is that Peak B may result from coherent superposition of different signals,including the components which form Peak A and Peak C.

关 键 词：NA Si(111)7×7 真空蒸镀 吸附 薄膜 二次谐波 

分 类 号：O485[理学—固体物理]