scholarly journals Thickness-Dependent Piezoelectric Property from Quasi-Two-Dimensional Zinc Oxide Nanosheets with Unit Cell Resolution

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Corey Carlos ◽  
Yizhan Wang ◽  
Jingyu Wang ◽  
Jun Li ◽  
Xudong Wang
Keyword(s):  
Zinc Oxide ◽  
Piezoelectric Property ◽  
Electrostatic Interactions ◽  
Electromechanical Coupling ◽  
Unit Cell ◽  
Force Microscopy ◽  
Atomic Force ◽  
Unit Cells ◽  
Quantitative Understanding ◽  
Zinc Oxide Nanosheets

A quantitative understanding of the nanoscale piezoelectric property will unlock many application potentials of the electromechanical coupling phenomenon under quantum confinement. In this work, we present an atomic force microscopy- (AFM-) based approach to the quantification of the nanometer-scale piezoelectric property from single-crystalline zinc oxide nanosheets (NSs) with thicknesses ranging from 1 to 4 nm. By identifying the appropriate driving potential, we minimized the influences from electrostatic interactions and tip-sample coupling, and extrapolated the thickness-dependent piezoelectric coefficient (d33). By averaging the measured d33 from NSs with the same number of unit cells in thickness, an intriguing tri-unit-cell relationship was observed. From NSs with 3n unit cell thickness (n=1, 2, 3), a bulk-like d33 at a value of ~9 pm/V was obtained, whereas NSs with other thickness showed a ~30% higher d33 of ~12 pm/V. Quantification of d33 as a function of ZnO unit cell numbers offers a new experimental discovery toward nanoscale piezoelectricity from nonlayered materials that are piezoelectric in bulk.

scholarly journals CHARACTERIZATION OF SURFACE OF THE (010) FACE OF BORAX CRYSTALS USING EX SITU ATOMIC FORCE MICROSCOPY (AFM):

2010 ◽  
Vol 5 (3) ◽  
pp. 274-277
Author(s):  
Suharso Suharso
Keyword(s):  
Atomic Force Microscopy ◽  
Unit Cell ◽  
Surface Topology ◽  
Ex Situ ◽  
Layered Compounds ◽  
Force Microscopy ◽  
Atomic Force ◽  
Unit Cells

The surface topology of borax crystals grown at a relative supersaturation of 0.21 has been investigated using ex situ atomic force microscopy (AFM). It was found that the cleavage of borax crystals along the (010) face planes has features of the cleavage of layered compounds, exhibiting cleavage steps of low heights. The step heights of the cleavage of the (010) face of borax crystal are from one unit cell to three unit cells of this face.   Keywords: AFM, cleavage, borax.

Zinc Oxide Thin Film Morphology as Function of Substrate Position During Sputtering Process

2021 ◽  
Vol 900 ◽  
pp. 103-111
Author(s):  
Christelle Habis ◽  
Jean Zaraket ◽  
Michel Aillerie
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Low Cost ◽  
Linear Increase ◽  
Oxide Thin Film ◽  
Central Position ◽  
Zinc Oxide Thin Film ◽  
Force Microscopy ◽  
Atomic Force ◽  
Great Transparency

Transparent conductive oxides are materials combining great transparency with high conductivity. In photovoltaic applications, they are developed under thin layer for the realization of upper electrodes of solar cells. Among transparent oxide materials, Zinc Oxide (ZnO) presents unique properties, starting with its first qualities to be abundant, low-cost and non-toxic oxide. Zinc Oxide thin film was deposited on rectangular glass substrate by magnetron sputtering. After an overview of the properties expected for good transparent conductive materials, the effect of distance from the center of the cell on the morphology of the film was investigated by Atomic Force Microscopy (AFM). The scanning was done on different area of the sample as function of the distance from the central position of the direct sputtering jet. As far as the distance increased, it has been noticed a quasi-linear increase in thickness of the ZnO deposited film and a change in the grain shape from spherical to pyramidal with an increase in the size of the particles. Controlling the sputtering distance allows the control of texture, thus of the Haze factor, the photo-generation of excitons, as well the optical transmission of the TCO layer and finally an improvement in the efficiency of the so-built photovoltaic cells.

Characteristics of Electron Transport Study of Composited Graphene-Zinc Oxide Thin Film Photoanode for Dye-Sensitized Solar Cells

2020 ◽  
Vol 307 ◽  
pp. 185-191
Author(s):  
Noor Syafiqah Samsi ◽  
N.A.S. Affendi ◽  
M.K. Yaakob ◽  
M.F.M. Taib ◽  
A. Lepit ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Dye Sensitized Solar Cells ◽  
Xrd Analysis ◽  
Oxide Thin Film ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Zno Nanosheets ◽  
High Degree ◽  
Sensitized Solar Cells

Graphene-Zinc Oxide (Gr-ZnO) nanocomposites films were successfully synthesized via facile electrodeposition method in an aqueous solution under Gr concentration conditions. Gr, as a highly conductive carbon, acts as an anchor for ZnO nanosheets and plays a substantial role in controlling the degree of dispersion of ZnO nanosheets onto indium-doped tin oxide (ITO) substrate to form Gr-ZnO nanocomposite. Atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) analysis of Gr-ZnO nanocomposite samples confirmed that the presence of ZnO nanosheets with a high degree of dispersity and crystallinity which is well linked to the thin layer of Gr nanoparticle on ITO substrate. The surface roughness of the films found increased to ~270 nm on Gr-ZnO as compared to Gr ~44 nm and ZnO ~3 nm. Further, the x-ray diffraction spectroscopy (XRD) analysis showed the result is in good agreement with Raman spectroscopy study. The cyclic voltammetry (CV) of Gr-ZnO nanocomposite revealed that the effect of electron-hole recombination process was increased and the presence of Gr in ZnO photoanode provides the fastest redox reaction and hence offers the fastest electron transfer in photoanode.

scholarly journals Nanohydrogels Based on Self-Assembly of Cationic Pullulan and Anionic Dextran Derivatives for Efficient Delivery of Piroxicam

Pharmaceutics ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 622 ◽  
Author(s):  
Dorota Lachowicz ◽  
Przemyslaw Mielczarek ◽  
Roma Wirecka ◽  
Katarzyna Berent ◽  
Anna Karewicz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Dextran Sulfate ◽  
Force Microscopy ◽  
Grafting Reaction ◽  
Atomic Force ◽  
Transmission Electron ◽  
Efficient Delivery ◽  
Model Drug

A cationic derivative of pullulan was obtained by grafting reaction and used together with dextran sulfate to form polysaccharide-based nanohydrogel cross-linked via electrostatic interactions between polyions. Due to the polycation-polyanion interactions nanohydrogel particles were formed instantly and spontaneously in water. The nanoparticles were colloidally stable and their size and surface charge could be controlled by the polycation/polyanion ratio. The morphology of the obtained particles was visualized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The resulting structures were spherical, with hydrodynamic diameters in the range of 100–150 nm. The binding constant (Ka) of a model drug, piroxicam, to the cationic pullulan (C-PUL) was determined by spectrophotometric measurements. The value of Ka was calculated according to the Benesi—Hildebrand equation to be (3.6 ± 0.2) × 103 M−1. After binding to cationic pullulan, piroxicam was effectively entrapped inside the nanohydrogel particles and released in a controlled way. The obtained system was efficiently taken up by cells and was shown to be biocompatible.

scholarly journals UV Sensitivity of Indium-Zinc Oxide Nanofibers

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Nadezhda Markova ◽  
Olga Berezina ◽  
Nikolay Avdeev ◽  
Alexander Pergament
Keyword(s):  
Zinc Oxide ◽  
Indium Content ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Indium Zinc Oxide ◽  
Electrospinning Method ◽  
Recovery Times ◽  
Response And Recovery

Indium-zinc oxide (IZO) nanofiber matrices are synthesized on SiO2-covered silicon substrates by the electrospinning method. The nanofibers’ dimensions, morphology, and crystalline structure are characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results of studying the electrical properties of nanofibers, as well as their sensitivity to UV radiation depending on the In-to-Zn concentration ratio, are presented. It is shown that the highest sensitivity to UV is observed at the indium content of about 50 atomic %. The photocurrent increment with respect to the dark current is more than 4 orders of magnitude. The response and recovery times are 60 and 500 sec, respectively. The results obtained suggest that IZO nanofibers can find application as UV sensors with improved characteristics.

Nanoscale surface electrical properties of zinc oxide films investigated by conducting atomic force microscopy

2007 ◽  
Vol 71 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Chang-Feng Yu ◽  
Sy-Hann Chen ◽  
Wen-Jia Xie ◽  
Yung-Shao Lin ◽  
Cheng-Yu Shen ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Oxide Films ◽  
Force Microscopy ◽  
Zinc Oxide Films ◽  
Atomic Force

scholarly journals Dissipation signals due to lateral tip oscillations in FM-AFM

2014 ◽  
Vol 5 ◽  
pp. 2048-2057 ◽  
Author(s):  
Michael Klocke ◽  
Dietrich E Wolf
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Energy ◽  
Unit Cell ◽  
Ionic Crystals ◽  
Force Microscopy ◽  
Normal Oscillation ◽  
Line Scan ◽  
Atomic Force ◽  
Dissipation Mechanism ◽  
Lateral Excitation

We study the coupling of lateral and normal tip oscillations and its effect on the imaging process of frequency-modulated dynamic atomic force microscopy. The coupling is induced by the interaction between tip and surface. Energy is transferred from the normal to the lateral excitation, which can be detected as damping of the cantilever oscillation. However, energy can be transferred back into the normal oscillation, if not dissipated by the usually uncontrolled mechanical damping of the lateral excitation. For certain cantilevers, this dissipation mechanism can lead to dissipation rates larger than 0.01 eV per period. The mechanism produces an atomic contrast for ionic crystals with two maxima per unit cell in a line scan.

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