摘要
在金(111)表面组装了具有不同末端基团的硫醇单层分子膜,并利用导电原子力显微镜研究了分子膜的电输运性质,发现不同末端基团的分子自组装膜的导电能力有明显差别.结合X射线光电子能谱,研究了末端基团中碳原子的结合能与相应硫醇分子电导的关系.结果表明不同末端基团分子膜导电能力的差别可归结为末端基团碳原子电子结合能的差异.结合能越高,末端基团电子的局域化程度越强,导致电子有效注入分子主链的势垒越高,从而减弱了分子膜对电子的输运能力.此外,实验还发现不同末端基团的硫醇单层分子膜有不同的表面电势,导致分子膜电流电压特性曲线的零点产生偏离.
The electronic transport properties of the alkanethiol self-assembled monolayer （SAM） with various terminal groups on Au （111） surfaces have been investigated by the conducting atomic force microscopy （CAFM）. The results show that the terminal group has obvious effect on the conductance of the SAMs. Combining the X-ray photoelectron spectrum （XPS） analysis and CAFM, we have further studied the relationship between the conductance of SAM and the Cls binding energy of the terminal group of the molecule. It is found that the higher the binding energy, the lower the conductance of the SAM. We attribute this behavior to that the high binding energy would induce strong electronic localization in the terminal group of alkanethiol molecule, which results in raising the effective harrier of the electron injecting into the molecular chains and reducing the transport ability of the electrons in the molecule. In addition, we also find that different group terminated SAMs have different surface potentials, which can shift the zero point of I-V curve of SAMs.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第3期1674-1679,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10274076
90406009)
中国科学院知识创新工程重大项目子课题(批准号:KJCX1-SW-07)资助的课题.~~
关键词
分子自组装膜
输运特性
末端基团
导电原子力显微镜
self-assembled monolayer, transport properties, terminal group, conducting atomic force microscopy
