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.

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.

scholarly journals Electron work function in individual multi-walled carbon nanotubes doped with nitrogen and boron

2020 ◽  
pp. 87-92
Author(s):  
N. A. Davletkildeev ◽  
◽  
D. V. Sokolov ◽  
E. Yu. Mosur ◽  
I. A. Lobov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrostatic Force ◽  
Contact Potential Difference ◽  
Electron Work Function ◽  
Chemical Vapor ◽  
Potential Difference ◽  
Contact Potential ◽  
Force Microscopy ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled undoped and doped with nitrogen and boron carbon nanotubes have been synthesized by chemical vapor deposition. Based on the analysis of images obtained by electrostatic force microscopy at various tip voltage, the value of the external contact potential difference between the tip and individual carbon nanotubes is determined. Using the obtained value of the contact potential difference, the electron work functions for undoped and doped with nitrogen and boron individual carbon nanotubes are calculated, which amounted to 4,7; 4,6 end 5,75 eV, respectively

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.

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.

scholarly journals Open-loop amplitude-modulation Kelvin probe force microscopy operated in single-pass PeakForce tapping mode

2021 ◽  
Vol 12 ◽  
pp. 1115-1126
Author(s):  
Gheorghe Stan ◽  
Pradeep Namboodiri
Keyword(s):  
Amplitude Modulation ◽  
Contact Potential Difference ◽  
Open Loop ◽  
Kelvin Probe Force Microscopy ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Force Microscopy ◽  
Single Pass ◽  
Afm Probe

The open-loop (OL) variant of Kelvin probe force microscopy (KPFM) provides access to the voltage response of the electrostatic interaction between a conductive atomic force microscopy (AFM) probe and the investigated sample. The measured response can be analyzed a posteriori, modeled, and interpreted to include various contributions from the probe geometry and imaged features of the sample. In contrast to this, the currently implemented closed-loop (CL) variants of KPFM, either amplitude-modulation (AM) or frequency-modulation (FM), solely report on their final product in terms of the tip–sample contact potential difference. In ambient atmosphere, both CL AM-KPFM and CL FM-KPFM work at their best during the lift part of a two-pass scanning mode to avoid the direct contact with the surface of the sample. In this work, a new OL AM-KPFM mode was implemented in the single-pass scan of the PeakForce Tapping (PFT) mode. The topographical and electrical components were combined in a single pass by applying the electrical modulation only in between the PFT tip–sample contacts, when the AFM probe separates from the sample. In this way, any contact and tunneling discharges are avoided and, yet, the location of the measured electrical tip–sample interaction is directly affixed to the topography rendered by the mechanical PFT modulation at each tap. Furthermore, because the detailed response of the cantilever to the bias stimulation was recorded, it was possible to analyze and separate an average contribution of the cantilever to the determined local contact potential difference between the AFM probe and the imaged sample. The removal of this unwanted contribution greatly improved the accuracy of the AM-KPFM measurements to the level of the FM-KPFM counterpart.

scholarly journals Local contact potential difference of molecular self-assemblies investigated by Kelvin probe force microscopy

2011 ◽  
Vol 99 (23) ◽  
pp. 233102 ◽  
Author(s):  
Evan J. Spadafora ◽  
Mathieu Linares ◽  
Wan Zaireen Nisa Yahya ◽  
Frédéric Lincker ◽  
Renaud Demadrille ◽  
...  
Keyword(s):  
Contact Potential Difference ◽  
Kelvin Probe Force Microscopy ◽  
Potential Difference ◽  
Kelvin Probe ◽  
Contact Potential ◽  
Force Microscopy ◽  
Local Contact
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