• Title/Summary/Keyword: AFM

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Probing of Electrochemical Reactions for Battery Applications by Atomic Force Microscopy

  • Kim, Yun-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.98.2-98.2
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    • 2013
  • Electrochemical phenomena underpin a broad spectrum of energy, chemical, and information technologies such as resistive memories and secondary batteries. The optimization of functionalities in these devices requires understanding electrochemical mechanisms on the nanoscale. Even though the nanoscale electrochemical phenomena have been studied by electron microscopies, these methods are limited for analyzing dynamic electrochemical behavior and there is still lack of information on the nanoscale electrochemical mechanisms. The alternative way can be an atomic force microscopy (AFM) because AFM allows nanoscale measurements and, furthermore, electrochemical reaction can be controlled by an application of electric field through AFM tip. Here, I will summarize recent studies to probe nanoscale electrochemical reaction in battery applications by AFM. In particular, we have recently developed electromechanical based AFM techniques for exploring reversible and irreversible electrochemical phenomena on the nanoscale. The present work suggests new strategies to explore fundamental electrochemical mechanisms using the AFM approach and eventually will provide a powerful paradigm for probing spatially resolved electrochemical information for energy applications.

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Atomic Force Microscopy (AFM) Tip based Nanoelectrode with Hydrogel Electrolyte and Application to Single-Nanoparticle Electrochemistry

  • Kyungsoon Park;Thanh Duc Dinh;Seongpil Hwang
    • Journal of Electrochemical Science and Technology
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    • v.15 no.2
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    • pp.261-267
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    • 2024
  • An unconventional fabrication technique of nanoelectrode was developed using atomic force microscopy (AFM) and hydrogel. Until now, the precise control of electroactive area down to a few nm2 has always been an obstacle, which limits the wide application of nanoelectrodes. Here, the nanometer-sized contact between the boron-doped diamond (BDD) as conductive AFM tip and the agarose hydrogel as solid electrolyte was well governed by the feedback amplitude of oscillation in the non-contact mode of AFM. Consequently, this low-cost and feasible approach gives rise to new possibilities for the fabrication of nanoelectrodes. The electroactive area controlled by the set point of AFM was investigated by cyclic voltammetry (CV) of the ferrocenmethanol (FcMeOH) combined with quasi-solid agarose hydrogel as an electrolyte. Single copper (Cu) nanoparticle was deposited at the apex of the AFM tip using this platform whose electrocatalytic activity for nitrate reduction was then investigated by CV and Field Emission-Scanning Electron Microscopy (FE-SEM), respectively.

An Enzyme-Linked Immunosorbent Assay for $Aflatoxin\;M_1$ in Cow's Milk without a Cleanup Procedure (희석에 의한 우유 중 $Aflatoxin\;M_1$의 효소면역측정법)

  • Shon, Dong-Hwa;Lim, Sun-Hee;Lee, Yin-Won
    • Korean Journal of Food Science and Technology
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    • v.28 no.6
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    • pp.1184-1187
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    • 1996
  • A simple and rapid detection system for $aflatoxin\;M_1\;(AFM_1)$ in cow's milk by an enzyme-linked immunosorbent assay (ELISA) was developed. Specific antibodies against $AFM_1$, conjugated to bovine serum albumin $(AFM_1-BSA)$ were raised in rabbits and purified. The cross-reactivities of the antibodies against aflatoxin analogs were less than 29.9%. When a competitive direct ELISA (cdELISA) for $AFM_1$, established by use of the antibodies was applied to the spike test of $AFM_1$ onto uncontaminated cow's milk, the assay recovery was unstable unless cow's milk was diluted to 40% (2:3) with phosphate buffered saline (PBS). In that condition of sample dilution, the mean ELISA recovery of $AFM_1$, from the cow's milk was 113% (coefficient of variation (CV) of each recovery percentage, 8.2%) in the range of $0.3{\sim}3.0\;ppb$. These results showed that the ELISA system could be a convenient tool to monitor the contamination of AFM1 more than 0.5 ppb in cow's milk (FDA allowance limit) easily.

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Atomic Force Microscopy Simulation for Si (001) Surface Defects (Si (001) 표면 결함 원자힘 현미경 전산모사)

  • Jo, Junyeong;Kim, Dae-Hee;Kim, Yurie;Kim, Ki-Yung;Kim, Yeong-Cheol
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.4
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    • pp.1-5
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    • 2018
  • Atomic force microscopy (AFM) simulation for Si (001) surface defects was conducted by using density functional theory (DFT). Three major defects on the Si (001) surface are difficult to analyze due to external noises that are always present in the images obtained by AFM. Noise-free surface defects obtained by simulation can help identify the real surface defects on AFM images. The surface defects were first optimized by using a DFT code. The AFM tip was designed by using five carbon atoms and positioned on the surface to calculate the system's energy. Forces between tip and surface were calculated from the energy data and converted into an AFM image. The simulated AFM images are noise-free and, therefore, can help evaluate the real surface defects present on the measured AFM images.

Vibro-Contact Analysis of AFM Tip on Polymer Surface (폴리머 표면측정을 위한 AFM 팁의 접촉-진동 해석)

  • Hong, Sang-Hyuk;Lee, Soo-Il
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.538-541
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    • 2005
  • In tapping mode atomic force microscopy(TM-AFM). the vibro-contact response of a resonating tip is used to measure the nanoscale topology and other properties of a sample surface. However, the nonlinear tip-surface interact ions can affect the tip response and destabilize the tapping mode control. Especially it is difficult to obtain a good scanned image of high adhesion surfaces such as polymers and biomoleculars using conventional tapping mode control. In this study, theoretical and experimental investigations are made on the nonlinear dynamics and control of TM-AFM. To analyze the complex dynamics and control of the tapping tip, the classical contact models are adopted due to the surface adhesion. Also we report the surface adhesion is an additional important parameter to determine the control stability of TM-AFM. In addition, we prove that it is more adequate to use Johnson-Kendall-Roberts (JKR) contact model to obtain a reasonable tapping response in AFM for the soft and high adhesion samples.

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Nanoscale Vibro-Contact Analysis of AFM Tip on Polymer Surface (폴리머 표면측정을 위한 AFM 팁의 나노스케일 접촉-진동 해석)

  • Lee, Soo-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.2 s.245
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    • pp.135-140
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    • 2006
  • In tapping mode atomic force microscopy (TM-AFM), the vibro-contact response of a resonating tip is used to measure the nanoscale topology and other properties of a sample surface. However, the nonlinear tipsurface interactions can affect the tip response and destabilize the tapping mode control. Especially it is difficult to obtain a good scanned image of high adhesion surfaces such as polymers and biomolecules using conventional tapping mode control. In this study, theoretical and experimental investigations are made on the nonlinear dynamics and control of TM-AFM. Also we report the surface adhesion is an additional important parameter to determine the control stability of TM-AFM. In addition, we proved that it was adequate to use Johnson-Kendall-Roberts (JKR) contact model to obtain a reasonable tapping response in AFM for the soft and high adhesion samples.

Theoretical Study of Scanning Probe Microscope Images of VTe2

  • Park, Sung-Soo;Lee, Jee-Young;Lee, Wang-Ro;Lee, Kee-Hag
    • Bulletin of the Korean Chemical Society
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    • v.28 no.1
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    • pp.81-84
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    • 2007
  • Ab initio periodic Hartree-Fock calculations with the full potential and minimum basis set are applied to interpretation of scanning tunneling microscope (STM) and atomic force microscope (AFM) images on 1TVTe2. Our results show that the simulated STM image shows asymmetry while the simulated AFM image shows the circular electron densities at the bright spots without asymmetry of electron density to agree with the experimental AFM image. The bright spots of both the STM and AFM images of VTe2 are associated with the surface Te atoms, while the patterns of bright spots of STM and AFM images are different.

Accurate Determination of Spring Constants of Micro Cantilevers for Quantified Force Metrology in AFM (AFM에서의 정량적 힘 측정을 위한 마이크로 캔틸레버의 강성 교정)

  • Kim, Min-Seok;Choi, Jae-Hyuk;Kim, Jong-Ho;Park, Yon-Kyu
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.6
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    • pp.96-104
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    • 2007
  • Calibration of the spring constants of atomic force microscopy (AFM) cantilevers is one of the issues in biomechanics and nanomechanies for quantified force metrology at pieo- or nano Newton level. In this paper, we present an AFM cantilever calibration system: the Nano Force Calibrator (NFC), which consists of a precision balance and a one-dimensional stage. Three types of AFM cantilevers (contact and tapping mode) with different shapes (beam and V) and spring constants (42, 1, 0.06 N $m^{-1}$) are investigated using the NFC. The calibration results show that the NFC can calibrate the micro cantilevers ranging from 0.01 ${\sim}$ 100 N $m^{-1}$ with relative uncertainties of less than 2%.

Determination of the Allowable Vibration Level of the Atomic Force Microscope Equipment (원자 현미경 장비의 바닥 진동(정상 상태) 허용 기준 결정)

  • Lee, Dong-Yeon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.161-164
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    • 2000
  • Currently, Atomic Force Microscope(AFM) has been widely used to measure the surface topography of a sample by detecting interaction force between atoms on the sample and extremely sharp probe tip. The vertical resolution of AFM is mainly determined by external vibration noise. The resolution of AFM shows different values for the different environment, thus it is necessary to determine relationship between the criteria and the resolution of AFM regardless of environment. In this paper, we discuss the allowable level of floor vibration for AFM equipment at given resolution. The vibration criteria can be used as reference data to design mechanical structure and to analyze the structural dynamics of AFM equipment.

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