LASER-FREQUENCY MIXING IN A SCANNING FORCE MICROSCOPE AND ITS APPLICATION TO DETECT LOCAL CONDUCTIVITY

被引:17
作者
VOLCKER, M [1 ]
KRIEGER, W [1 ]
WALTHER, H [1 ]
机构
[1] UNIV MUNICH,SEKT PHYS,D-85748 GARCHING,GERMANY
来源
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B | 1994年 / 12卷 / 03期
关键词
D O I
10.1116/1.587723
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
When two infrared laser beams are coupled into the tip of a scanning tunneling microscope, the difference frequency is generated in the tunneling junction and can be observed via an emitted wave. In order to obtain a detectable signal also in the case of a force microscope, a locally conducting area has to be opposite to the tip. This allows one to distinguish between conducting and nonconducting regions of a sample when a force microscope is used for the experiments. The difference-frequency signal is found to decrease with decreasing size of conducting islands. The detection is limited at present to islands larger than about 1 mum in diameter. A simple model for the difference-frequency generation in the tip-sample junction is presented. From this model, improvements of the method can be derived which lead to the possibility that still smaller structures can be investigated.
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页码:2129 / 2132
页数:4
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