Conductive AFM: Probing Nano-scale Electrical Properties of Model Cell Membranes

2012 ◽  
Vol 1465 ◽  
Author(s):  
Paul Farrar ◽  
Del Atkinson ◽  
Andrew J. Gallant
Keyword(s):  
Lipid Bilayers ◽  
Electrical Contact ◽  
Pyrolytic Graphite ◽  
Elastic Response ◽  
Electrical Measurements ◽  
Contact Mode ◽  
Biologically Relevant ◽  
Atomic Force ◽  
Current Voltage ◽  
Model Cell

ABSTRACTBiologically relevant lipid bilayers supported on highly ordered pyrolytic graphite (HOPG) were probed both mechanically and electrically with a Conductive Atomic Force Microscope (C-AFM) capable of measuring ultra-low currents. Results show that these membranes undergo an elastic response up to 26 nN on average when compressed with an AFM tip. Measuring the films with a low contact force demonstrates that contact mode AFM can be used repeatedly to image without damaging the film. Based on current-voltage measurements made with the C-AFM, it is shown that apparently high resistances seen for the films could be the result of variable electrical contact between the tip and surface. As a result, the paper proposes that the deflection of the cantilever should always be measured in order to ensure knowledge of the location of the tip during all electrical measurements.

Nanoprobing Applications with Capacitance-Voltage and Pulsed Current-Voltage Measurements for Device Failure Analysis

2015 ◽  
Author(s):  
LiLung Lai ◽  
Nan Li ◽  
Qi Zhang ◽  
Tim Bao ◽  
Robert Newton
Keyword(s):  
Failure Analysis ◽  
High Speed ◽  
Pulsed Current ◽  
Electrical Measurements ◽  
Device Failure ◽  
Mos Devices ◽  
Atomic Force ◽  
Current Voltage ◽  
Capacitance Voltage ◽  
Rising Time

Abstract Owing to the advancing progress of electrical measurements using SEM (Scanning Electron Microscope) or AFM (Atomic Force Microscope) based nanoprober systems on nanoscale devices in the modern semiconductor laboratory, we already have the capability to apply DC sweep for quasi-static I-V (Current-Voltage), high speed pulsing waveform for the dynamic I-V, and AC imposed for C-V (Capacitance-Voltage) analysis to the MOS devices. The available frequency is up to 100MHz at the current techniques. The specification of pulsed falling/rising time is around 10-1ns and the measurable capacitance can be available down to 50aF, for the nano-dimension down to 14nm. The mechanisms of dynamic applications are somewhat deeper than quasi-static current-voltage analysis. Regarding the operation, it is complicated for pulsing function but much easy for C-V. The effective FA (Failure Analysis) applications include the detection of resistive gate and analysis for abnormal channel doping issue.

Manipulation of Nickel Nanoparticles Deposited on HOPG

2004 ◽  
Vol 853 ◽  
Author(s):  
Massood Z. Atashbar ◽  
Valery N. Bliznyuk ◽  
Srikanth Singamaneni
Keyword(s):  
Atomic Force Microscope ◽  
Magnetic Force ◽  
Nickel Nanoparticles ◽  
Pyrolytic Graphite ◽  
Critical Force ◽  
Contact Mode ◽  
Cyclic Voltametry ◽  
Atomic Force ◽  
Nickel Nanowires ◽  
Plating Solution

ABSTRACTNickel nanowires were fabricated by electrodepositing Ni from an aqueous plating solution onto the step edges of Highly Oriented Pyrolytic Graphite (HOPG). Freshly cleaved HOPG was exposed to a plating solution of nickel and electro chemically deposited by cyclic voltametry. The morphology of the deposited nanoparticles was studied using an Atomic Force Microscope (AFM) in non-contact mode. The magnetic force of interaction between the nanoparticles was studied by magnetizing the particles. The critical force to displace the nanoparticles was estimated using contact mode of AFM.

Electronic Transport Properties of Chemical Gas Sensor Using Conducting Polymer PAni

2006 ◽  
Vol 326-328 ◽  
pp. 1363-1366 ◽  
Author(s):  
Jae Jong Lee ◽  
Soo Yeon Park ◽  
Seung Woo Lee ◽  
In Deok Jeon
Keyword(s):  
Conducting Polymer ◽  
Isopropyl Alcohol ◽  
Low Noise ◽  
Electrical Measurements ◽  
Isobutyl Ketone ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Measured Distance ◽  
Lift Off

The conducting polymer PAni is coated on Au electrode sample by spin coater on 500rpm and 3000rpm for 5sec and 30sec. Then, it was drying 10min at 180C. The layer thickness was 140~200nm. The electrodes were fabricated the resist pattern by electron beam writing machine which was performed on a Raith75 e-Line on the PMMA 950K, thickness 100nm. The electrodes were written at an electron does of 200uAs/cm2 and developed for 40sec in a 1:3 MIBK (methyl-isobutyl-ketone): IPA (isopropyl alcohol) solution. Metal lift-off of the PMMA in acetone was preceded by an e-beam evaporation consisting of 50Å Cr and 250Å Au. Electrical measurements were performed on low-noise commercial probe stations equipped. We measured distance between the electrodes ranges from a few tens of nanometer to hundreds nanometer by AFM (Atomic Force Microscopy) which was done with silicon tips in non-contact mode on a PSIA, XE-100.

Scanning Force Microscopy Study of Ultrathin Films of Nickel-Phthalocyanine on Graphite

1998 ◽  
Vol 05 (01) ◽  
pp. 433-436 ◽  
Author(s):  
S. Santucci ◽  
S. Di Nardo ◽  
L. Lozzi ◽  
L. Ottaviano ◽  
M. Passacantando ◽  
...  
Keyword(s):  
Pyrolytic Graphite ◽  
Scanning Force Microscopy ◽  
Microscopy Study ◽  
Ex Situ ◽  
Contact Mode ◽  
Force Microscopy ◽  
Nickel Phthalocyanine ◽  
Atomic Force ◽  
Scanning Force

Small amounts of purified nickel-phthalocyanine (Ni-PC) have been deposited at room temperature in ultrahigh vacuum onto highly oriented pyrolytic graphite, and studied "in situ" and "ex situ" (in air) with two different atomic force microscopes. The measurements have been taken on samples as prepared either subsequently annealed at 300°C. The growth mode is not uniform; the PC molecules coalesce into small submicrometric crystallites in the critical size range where the transition from the α to the β crystalline phase of phthalocyanines takes place. We show images of both α-like and β-like crystallites. A contact mode AFM image of an α-like crystallite showing intramolecular resolution is also presented.

Current-Voltage Measurements as a Function of Applied Tip Force on Pentacene by Conducting Probe Microscopy

2000 ◽  
Vol 660 ◽  
Author(s):  
Serkan Zorba ◽  
Neil J. Watkins ◽  
Li Yan ◽  
Yongli Gao
Keyword(s):  
Organic Semiconductor ◽  
Electrical Contact ◽  
Hole Injection ◽  
Atomic Force ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Tunneling Phenomenon ◽  
Injection Barrier ◽  
Reproducible Manner ◽  
Increasing Load

ABSTRACTCurrent-voltage characteristics of organic semiconductor pentacene were studied as a function of applied tip force using conducting probe atomic force microscope. I-V measurements were performed on 150Å and 300Å pentacene films. No electrical contact was observed until 20 nN of tip force for the 150Å film coverage, whereas electrical contact was established easily with a few nN of tip force values for the 300Å film coverage. On both films, once an electrical contact was obtained, the conductance was observed to increase with increasing load. At about 50 nN and higher loads we lost electrical contact in both cases in a reproducible manner. While I-V on 150Å pentacene film showed a rectifying behavior, I-V on 300Å pentacene looked like typical I-V curves of tunneling phenomenon. From these measurements, we have estimated a hole injection barrier of about 0.76 eV and a band gap of about 2.00 eV for pentacene. These results are in agreement with those in the literature.

NANOBUBBLES AT THE INTERFACE OF HOPG AND ETHANOL SOLUTION

2005 ◽  
Vol 04 (03) ◽  
pp. 399-407 ◽  
Author(s):  
X. H. ZHANG ◽  
Z. H. WU ◽  
X. D. ZHANG ◽  
G. LI ◽  
J. HU
Keyword(s):  
Pyrolytic Graphite ◽  
Ethanol Solution ◽  
Solid Surfaces ◽  
Nanometer Scale ◽  
Interfacial Phenomenon ◽  
Destructive Effect ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Imaging

Recently, it has been put forward that bubbles of nanometer scale (nanobubbles) can exist on solid surfaces immersed in aqueous solution, especially on hydrophobic substrates. This interfacial phenomenon has invited extensive interests in both scientific and commercial fields. Experimental evidence including the study of atomic force microscopy (AFM) has been provided to support the existence of nanobubbles. But, there are still many debates in this field. In this paper, a degassing process is combined with direct AFM imaging to prove that the features in the AFM images are nanobubbles. It is found that the morphology of nanobubbles on the highly oriented pyrolytic graphite (HOPG) surface was noticeably deformed during contact mode imaging and their size is extremely sensitive to the imaging force of AFM. By observing nanobubbles in ethanol solution of different concentrations, we found that ethanol solution more concentrated than 20% (V/V) may have a destructive effect on nanobubbles.

scholarly journals ELECTRONIC PROPERTIES OF THIN FILMS SUBLIMED FROM La@C82 AND Li@C60

NANO ◽  
2008 ◽  
Vol 03 (03) ◽  
pp. 155-160 ◽  
Author(s):  
V. N. POPOK ◽  
A. V. GROMOV ◽  
M. JÖNSSON ◽  
A. TANINAKA ◽  
H. SHINOHARA ◽  
...  
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Film Structure ◽  
Ambient Atmosphere ◽  
Room Temperature Resistivity ◽  
Electrical Measurements ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Temperature Dependences

La @ C 82 and Li @ C 60 thin films obtained by sublimation in vacuum are studied using four-probe current–voltage measurements and atomic force microscopy. In situ electrical measurements show semiconducting behavior of both films with room-temperature resistivity of 21 ± 8 and 1230 ± 50 Ω · cm for the La @ C 82 and Li @ C 60, respectively. A variable range hopping mechanism of conductance is suggested from the temperature dependences of resistance. The activation energies for electron transport are calculated for both metallofullerenes. Irreversible changes to the Li @ C 60 film structure increasing the film resistivity to values typical for C 60 are found at elevated temperatures. The effect of exposure to ambient atmosphere on the conductance of the films is discussed.

scholarly journals Study of the charge transfer process in the polyaniline/graphite heterojunction by conductive atomic force microscopy

2020 ◽  
pp. 94-98
Author(s):  
N. A. Davletkildeev ◽  
Keyword(s):  
Atomic Force Microscopy ◽  
Oxidative Polymerization ◽  
Pyrolytic Graphite ◽  
Thin Layers ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Current Voltage Characteristics

Thin layers of polyaniline on the surface of highly oriented pyrolytic graphite are obtained by in-situ chemical oxidative polymerization of aniline. The current-voltage characteristics of the tip/polyaniline/graphite contact, which have a form characteristic of tunnel contacts, have been measured by the method of conducting atomic force microscopy. By modeling the current-voltage characteristics using the Simmons model, the width of the potential barrier is determined, which for the investigated heterojunction is 0,5 nm

Current-voltage Characteristics of Single CdSe Colloidal Nanodots Measured by Conductive-tip Atomic Force Microscopy

2002 ◽  
Vol 737 ◽  
Author(s):  
Ichiro Tanaka ◽  
Eri Kawasaki ◽  
O. Ohtsuki ◽  
K. Uno ◽  
M. Hara ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Room Temperature ◽  
Sample Surface ◽  
Self Assembled Monolayer ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Being Moved

ABSTRACTWe have investigated current-voltage characteristics of individual CdSe colloidal nanodots by conductive-tip atomic force microscopy (AFM). The colloidal nanodots were spun-coat and scattered on a self-assembled monolayer of thiophene molecules formed on Au (111) surfaces for single dot measurements. A thin SiO2 layer was deposited on the sample surface in order to prevent the dots being moved by the tip during measurement. We imaged the topography of isolated single dots by AFM operated in contact mode, and measured current-voltage characteristics with the conductive tip positioned on single dots; large conductivity changes which suggest resonant tunneling through a quantized energy level in the dot was observed even at room temperature.

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