Study of the electron dynamics on semiconductor surfaces by the use of the time-resolved two-photoelectron spectroscopy with the femto-second pulse-laser.

利用飞秒脉冲激光的时间分辨双光电子能谱研究半导体表面的电子动力学。

基本信息

批准号：
16540285
负责人：
TANAKA Shin-ichiro
金额：
$ 2.5万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

In this study, I constructed the experimental system consisting of a time-resolved two-photon photoelectron spectroscopy (TR2PPE) with a fsec-pulse laser, scanning tunneling microscopy (STM), and the sample treatment system. Using this system, the electron property and dynamics of the Si(001) surface is investigated, and the following results are obtained.1)The temporal evolution of electrons which temporarily occupy the unoccupied surface dangling bond state (D_<down>) and the bulk conduction band as a result of the photoexcitation is studied. The sub-ns decay of π^* (electron population at D_<down>) and C^* (electron population at the bulk conduction band near the surface) after the photo-excitation of the clean Si(001) surface. A prominent excitation-wavelength dependent decay in sub-ns temporal domain was observed for both π^* and C^*, and they are proportional with each other at temporal regime longer than 40 ps after the excitation. The results reveal a crucial role of the bulk-to-surface transition in the carrier dynamics on this surface, together with a short lifetime (<10ps) of electrons at the D_<down> state. The surface recombination velocity S is determined by comparing the solution of the diffusion equation.2)2PPE spectroscopy was utilized for investigating the electronic properties and electron dynamics on the Si(001)(2x1) surface on which the density of C-defect was examined with STM It was found that the Fermi-level pinning occurs at 〜0.8eV with respect to CBM when C-defect density is more than 0.05 monolayer on the p-type Si(001)(2x1) surface. The electron dynamics on Si(001) is affected by the C-defect on the surface. A change in the inverse of the product of the bulk-to-surface electron transition rate S and the extinction lifetime τ of the surface excited electron is examined as a function of the C-defect density, and found that it becomes twice when the C-defect density reaches to 0.1 ML on the surface.

在这项研究中，我构建了由时间分辨的两光子光电光谱（TR2PPE）组成的实验系统，该光谱光谱（TR2PPE）和FSEC-PULSE激光器，扫描隧道显微镜（STM）和样品处理系统。使用该系统，研究了SI（001）表面的电子特性和动力学，并获得以下结果。1）临时占据无置置的表面悬挂键状态（D_ <dound>）的电子暂时演变，并研究了散装的传统传统带作为光盘的结果。 π^*（d_ <dound>的电子种群）和c^*（表面附近的散装传导带的电子种群）的子NS衰减，在光驱时（001）表面进行了光兴趣。对于π^*和c^*，观察到了子-NS临时结构域中的显着兴奋波长衰减，并且在兴奋后，它们在临时状态下彼此成比例超过40 ps。结果揭示了该表面上载体动力学中散装到地面过渡的关键作用，以及在D_ <dound>状态下的寿命短（<10ps）。 The surface recombination velocity S is determined by comparing the solution of the diffusion equation.2)2PPE spectroscopy was utilized for investigating the electronic properties and electronic dynamics on the Si(001)(2x1) surface on which the density of C-defect was examined with STM It was found that the Fermi-level pinning occurs at ~0.8eV with respect to CBM when C-defect density is more than p型Si（001）（2x1）表面上的0.05单层。 Si（001）上的电子动力学受表面上的C-DEFECT的影响。大量到表面电子过渡速率s的乘积倒数和表面激发电子的延伸寿命τ的倒数是作为CEFECT密度的函数检查的，并发现当C-Defect密度达到表面上的0.1 ml时，它变为两倍。