权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Construction of the apparatus for the local photoelectron spectroscopy

局域光电子能谱装置的构建

基本信息

批准号：
09554015
负责人：
NISHITANI Ryusuke
金额：
$ 8万
依托单位：
Kyushu Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

The local ultraviolet (UV) photoemission has been observed by using STM for the local characterization of the metal films. The change in the photoelectron current along and normal to the sample surface has been measured as well as the bias dependence of photoelectron current. The local photoelectron current is detected by STM tip which is coated with insulator except for the area of tip apex. The photoelectrons are excited by UV light of Ar ion (11.8 eV). The measurements are made for Co and Ni metal films. The measurement of photoelectron emission has been made for the Co and Ni films during irradiation of UV light. The images during UV irradiation are dependent on the feedback current which includes tunneling current and photoelectron current. The observed photoelectron image shows the occurrence of local photoemission within the region of 20 nm along the surface and 15 nm along the normal to the surface. We have also measured the current as functions of the tip-sample distance and STM bias voltage. The current changes approximately as the squared power laws with the tip-sample distance, indicating that the change in the photoelectron current at tip can be explained in terms of the change in the detection solid angle of detection area at STM tip with lithe change in the tip-sample distance. This fact suggests that the photoelectron current is not uniformly distributed, but photoelectrons emit radially from the area near the tip-sample junction.

利用扫描隧道显微镜对金属薄膜进行局域表征，观察到了局域紫外光发射。测量了光电子电流沿样品表面和垂直于样品表面的变化，以及光电子电流的偏置依赖关系。扫描隧道显微镜针尖除了针尖尖端区域外，还涂有绝缘体，可以检测到局部光电子电流。光电子被Ar离子(11.8 eV)的紫外光激发。对Co和Ni金属薄膜进行了测量。测量了Co、Ni薄膜在紫外光照射下的光电子发射。紫外光照射过程中的图像依赖于反馈电流，反馈电流包括隧道电流和光电子电流。观察到的光电子图像显示，在沿表面20 nm和沿表面法线15 nm的区域内发生了局部光电子发射。我们还测量了针尖-样品距离和STM偏置电压对电流的影响。电流随针尖-样品距离的变化近似为平方幂规律，说明针尖光电子电流的变化可以用针尖-样品距离变化引起的STM针尖探测区域探测立体角的变化来解释。这一事实表明，光电子电流并不是均匀分布的，而是从针尖-样品结附近的区域径向发射光电子。