Changes of Contact Potential Difference Induced by Frictional Damage in Ultrahigh Vacuum

1999 ◽  
Vol 558 ◽  
Author(s):  
L. Zhang ◽  
K. Nakayama
Keyword(s):  
Atomic Force Microscope ◽  
Work Function ◽  
Contact Potential Difference ◽  
Ultrahigh Vacuum ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Light Load ◽  
Atomic Force ◽  
The Difference

ABSTRACTThe work function is one of the most fundamental properties of a metal surface. To clarify frictional electrification phenomena, the effects of frictional damage on the contact potential difference (CPD), which is defined by the difference between the work functions of two contacting surfaces, were investigated. Au(111) and Si(111) surfaces were scratched in an ultrahigh vacuum under a light load with the Si cantilever tip of an atomic force microscope. The contact potential difference between the scratched surface and the tip whose work function was known was measured using an ultrahigh vacuum scanning Kelvin probe force microscope (SKPM). Simultaneously, the noncontact atomic force microscope (NC-AFM) images were observed in situ. The CPD images showed clear changes between the areas with and without scratching, corresponding to the scratching track on the NC-AFM images.

scholarly journals Coupled Investigation of Contact Potential and Microstructure Evolution of Ultra-Thin AlOx for Crystalline Si Passivation

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1803
Author(s):  
Zhen Zheng ◽  
Junyang An ◽  
Ruiling Gong ◽  
Yuheng Zeng ◽  
Jichun Ye ◽  
...  
Keyword(s):  
Structural Changes ◽  
Silicon Oxide ◽  
Crystalline Silicon ◽  
Contact Potential Difference ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Carrier Lifetimes ◽  
Transmission Electron ◽  
Effective Carrier

In this work, we report the same trends for the contact potential difference measured by Kelvin probe force microscopy and the effective carrier lifetime on crystalline silicon (c-Si) wafers passivated by AlOx layers of different thicknesses and submitted to annealing under various conditions. The changes in contact potential difference values and in the effective carrier lifetimes of the wafers are discussed in view of structural changes of the c-Si/SiO2/AlOx interface thanks to high resolution transmission electron microscopy. Indeed, we observed the presence of a crystalline silicon oxide interfacial layer in as-deposited (200 °C) AlOx, and a phase transformation from crystalline to amorphous silicon oxide when they were annealed in vacuum at 300 °C.

Comparative Surface Studies at Atomic Resolution with Ultrahigh Vacuum Variable-Temperature Atomic Force and Scanning Tunneling Microscopes

1999 ◽  
Vol 5 (3) ◽  
pp. 208-215 ◽  
Author(s):  
Masashi Iwatsuki ◽  
Kazuyuki Suzuki ◽  
Shin-ich Kitamura ◽  
Mike Kersker
Keyword(s):  
Detection Method ◽  
Variable Temperature ◽  
Contact Potential Difference ◽  
Oscillation Amplitude ◽  
Ultrahigh Vacuum ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Contact Potential ◽  
Atomic Force ◽  
Temperature Scanning

With the ultrahigh vacuum variable-temperature scanning tunneling microscope (UHV-VT-STM), atomic-level observation has been achieved. An ultrahigh vacuum atomic force microscope (UHV-AFM) has also been developed, with success in obtaining atom images where observation in noncontact (NC) mode with a frequency modulation (FM) detection method was attempted. Using the FM detection method in the constant oscillation amplitude of the cantilever excitation mode, we have obtained atomic-resolution images of Si(111) 7 × 7 structures and Si(100) 2 × 1 structures and other structures together with STM images in an ultrahigh vacuum environment. Also shown here are contact potential difference (CPD) images using the NC-AFM method.

scholarly journals Imaging the surface potential at the steps on the rutile TiO2(110) surface by Kelvin probe force microscopy

2019 ◽  
Vol 10 ◽  
pp. 1228-1236 ◽  
Author(s):  
Masato Miyazaki ◽  
Huan Fei Wen ◽  
Quanzhen Zhang ◽  
Yuuki Adachi ◽  
Jan Brndiar ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Surface Potential ◽  
Active Sites ◽  
Contact Potential Difference ◽  
Kelvin Probe Force Microscopy ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Force Microscopy ◽  
First Time

Although step structures have generally been considered to be active sites, their role on a TiO2 surface in catalytic reactions is poorly understood. In this study, we measured the contact potential difference around the steps on a rutile TiO2(110)-(1 × 1) surface with O2 exposure using Kelvin probe force microscopy. A drop in contact potential difference was observed at the steps, indicating that the work function locally decreased. Moreover, for the first time, we found that the drop in contact potential difference at a <1−11> step was larger than that at a <001> step. We propose a model for interpreting the surface potential at the steps by combining the upward dipole moment, in analogy to the Smoluchowski effect, and the local dipole moment of surface atoms. This local change in surface potential provides insight into the important role of the steps in the catalytic reaction.

Contact Potential Difference as a Non-Destructive Testing of Steel

2021 ◽  
Vol 316 ◽  
pp. 258-263
Author(s):  
L.P. Aref'eva ◽  
A.G. Sukijazov ◽  
Yu.V. Dolgachev
Keyword(s):  
Chemical Composition ◽  
Contact Potential Difference ◽  
Electron Work Function ◽  
Sharp Decrease ◽  
Sample Surface ◽  
Probe Method ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Kelvin Probe Method

For steels of different grades, the effect of the chemical composition, structure, and surface etching on the contact potential difference is studied using the Kelvin probe method. It was shown experimentally that, with a change in the structure and chemical composition, the contact potential difference changes. Etching the surface of the steel with a 4% solution of nitric acid leads to a sharp decrease in the magnitude of the contact potential difference, which allows us to conclude that the value of the electron work function from the sample surface increases. The ability to control the composition and structure of the material by the Kelvin probe method is shown.

Conception of the Kelvin Method on the Basis of a Mechanic-Electrical Transformation

2018 ◽  
Vol 63 (3) ◽  
pp. 269
Author(s):  
Yu. S. Zharkikh ◽  
S. V. Lysochenko
Keyword(s):  
Mechanical Energy ◽  
Contact Potential Difference ◽  
Electrical Potential ◽  
Potential Difference ◽  
Atomic Scale ◽  
Measured Signal ◽  
Electrical Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Electrostatic Charges

The Kelvin method was based on the concept of the dynamic capacitor recharging by a contact potential difference. The present paper draws attention to the fact that the contact potential difference is not the same physical agent as the electrical potential difference due to the electromotive force. It cannot act as an active electrical voltage and, accordingly, cause the flow of an electric recharging current. The real reason for the appearance of a measured signal is the transformation of the electrode movement mechanical energy into the electric current energy. The current is generated due to periodic changes in the screening conditions of electrostatic charges above the investigated surface. Investigations are made of the method sensitivity to the amount of charges on the sample surface. It is shown that the measurement results are interpreted without invoking the ideas of the work function. Therefore, the method can besuccessfully used in studies of organic and biological materials and electrolytes. The proposed mechanism is applicable in both the investigations of macroscopic distributions of the surfacecharge and the atomic scale in the Kelvin probe force microscopy.

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