Role of a covalent bonding interaction in noncontact-mode atomic-force microscopy on Si(111)7x7

被引：116

作者：

Uchihashi, T ^{[1
]}

Sugawara, Y ^{[1
]}

Tsukamoto, T ^{[1
]}

Ohta, M ^{[1
]}

Morita, S ^{[1
]}

Suzuki, M ^{[1
]}

机构：

[1] NTT ADV TECHNOL CO,ATSUGI,KANAGAWA 24301,JAPAN

来源：

PHYSICAL REVIEW B | 1997年 / 56卷 / 15期

关键词：

D O I：

10.1103/PhysRevB.56.9834

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We experimentally investigated a force interaction between a Si tip and the Si(111)7x7 reconstructed surface using a noncontact-mode atomic-force microscope (AFM) in ultrahigh vacuum. Two types of force gradient curves with and without discontinuity were found. Furthermore, the correlation between the force gradient curves and the noncontact AFM image contrasts has been clarified. The image contrast was very weak in the case of the force gradient curve without discontinuity, while it was clearly enhanced and the contrast. between inequivalent adatoms was obtained in the case of the force gradient curve with discontinuity. The discontinuity of the force gradient curve can be explained by a model which considers a crossover between physical bonding and chemical bonding interactions between tip and sample. This model suggests that the weak contrast image reflects the variation in van der Waals and/or electrostatic force interactions, while the strong contrast image reflects the variation in a chemical reactivity on Si adatoms.

引用

页码：9834 / 9840

页数：7

共 28 条

[1] FREQUENCY-MODULATION DETECTION USING HIGH-Q CANTILEVERS FOR ENHANCED FORCE MICROSCOPE SENSITIVITY [J].