Force Microscopy In Piezoresponse Mode Research Articles

Functionalized Wood Veneers as Vibration Sensors: Exploring Wood Piezoelectricity and Hierarchical Structure Effects.

Functional wood materials often rely on active additives due to the weak piezoelectric response of wood itself. Here, we chemically modify wood to form functionalized, eco-friendly wood veneer for self-powered vibration sensors. Only the piezoelectricity of the cellulose microfibrils is used, where the drastic improvement comes only from molecular and nanoscale wood structure tuning. Sequential wood modifications (delignification, oxidation, and model fluorination) are performed, and effects on vibration sensing abilities are investigated. Wood veneer piezoelectricity is characterized by the piezoresponse force microscopy mode in atomic force microscopy. Delignification, oxidation, and model fluorination of wood-based sensors provide output voltages of 11.4, 23.2, and 60 mV by facilitating cellulose microfibril deformation. The vibration sensing ability correlates with improved piezoelectricity and increased cellulose deformation, most likely by large, local cell wall bending. This shows that nanostructural wood materials design can tailor the functional properties of wood devices with potential in sustainable nanotechnology.

Model of frequency-modulated atomic force microscopy for interpretation of noncontact piezoresponse measurements

A model to describe the behavior of the probe of an atomic force microscope (AFM) operated in frequency modulation (FM) dynamic mode with constant excitation (CE) is developed, with the aim of describing recent experiments after the introduction of a noncontact piezoresponse force microscopy (PFM) method based on such an operation mode, named CE-FM-PFM (Labardi et al 2020 Nanotechnology 31, 075707). The model provides insight into improving the accuracy of converse piezoelectric coefficient (d33) measurements on the local scale in this PFM mode. Its rather general applicability helps to quantify the residual electrostatic contribution in local piezoresponse measurements by AFM, which is anticipated to be strongly mitigated in the CE-FM-PFM compared to the more standard contact-mode PFM.

Local electromechanical characterization of Pr doped BiFeO3 ceramics

Local electromechanical (EM) measurements were performed in Pr doped BiFeO3 (BPFO) ceramics via piezoresponse force microscopy (PFM). The results revealed that local EM response was different from the macroscopic one due to the large contribution of the leakage current. The locally measured response was used to evaluate effective piezoelectric coefficient d33 of the material. The multi-frequency PFM mode with additional compensation of the cantilever-surface Coulomb interaction under application of the external DC bias provided the most accurate values of the effective d33 coefficient and allowed studying its surface distribution and residual depolarization field distribution across the surface of BPFO ceramics.

Exploring piezoelectric properties of III–V nanowires using piezo-response force microscopy

Semiconducting III–V materials exhibiting piezoelectric properties are much sought after due to their potential applications in piezotronic and piezo-phototronic devices. Nanowires (NWs) of III–V semiconductors are particularly interesting in this respect due to the occurrence of the wurtzite (WZ) structure commonly associated with enhanced piezoelectric properties, as opposed to the zinc blende (ZB) structure that is typically observed in the bulk. However, performing direct measurements of the piezoelectric properties of III–V NWs using piezo-response force microscopy (PFM) is challenging, and the analysis and interpretation of such measurements is far from trivial. Here we present detailed finite element simulations of single GaAs NWs, with both WZ and ZB crystalline structure, scanned by an atomic force microscope tip in PFM mode, demonstrating the effect of the non-uniform electric field between the tip and NW, scan direction, as well as NW orientation on the resulting PFM signal. We also report PFM data from single GaAs and InP NWs with both ZB and WZ structure, grown by molecular beam epitaxy, based on a novel non-destructive intermittent contact PFM mode. We explain our experimental data in the framework of our simulations, and for the first time, extract an experimental value for the axial piezoelectric coefficient of WZ InP, pm V−1. The methods and analysis described here are particularly relevant for the investigation of piezoelectric properties in a wide range of semiconducting III–V NW systems.

Quantitative lateral and vertical piezoresponse force microscopy on a PbTiO3 single crystal

Piezoresponse force microscopy (PFM) has emerged as a powerful tool for research in ferroelectric and piezoelectric materials. While the vertical PFM (VPFM) mode is well understood and applied at a quantitative level, the lateral PFM (LPFM) mode is rarely quantified, mainly due to the lack of a practical calibration methodology. Here by PFM imaging on a LiNbO3 180° domain wall, we demonstrate a convenient way to achieve simultaneous VPFM and LPFM calibrations. Using these calibrations, we perform a full quantitative VPFM and LPFM measurement on a (001)-cut PbTiO3 single crystal. The measured effective piezoelectric coefficients d33eff and d35eff together naturally provide more information on a material's local tensorial electromechanical properties. The proposed approach can be applied to a wide variety of ferroelectric and piezoelectric systems.

Statics and Dynamics of Ferroelectric Domains in Diisopropylammonium Bromide.

An electrically written domain structure formed by a biased tip, and visualized in the piezoresponse force microscopy mode, shows stable charged domain walls in the organic ferroelectric diisopropylammonium chloride microcrystal.

Investigation of the Orientational Dependence the Lateral Piesoresponse in Y–cut Periodically Poled Lithium Niobate Single Crystals

The angular dependence of the lateral component piesoresponse in Y−cut lithium niobate single crystals with a regular domain structure was investigated in piezoresponse force microscopy mode. It is shown that visualization of the domain structure is determined by the orientation of the X direction of the crystal relative to the scan direction: the greatest contrast between domains with opposite orientation of the polarization vectors takes place at locations along an X−direction line and the direction of scanning.

Electric field-induced switching of nanometer-sized twin related domains in [formula omitted]–0.09PbTiO [formula omitted] single crystal near a morphotropic phase boundary composition

Electric field-induced switching of nanometer-sized twin related domains were investigated in rhombohedral (R), tetragonal (T) and monoclinic (M) phases in 0.91Pb(Zn 1/3Nb 2/3)O 3–0.09PbTiO 3 single crystal by means of scanning force microscopy in piezoresponse mode. Their domain sizes in R, T and M phases were found to be 10–100, ∼200 and 100–300 nm length, respectively. The nucleation and growth in domain switching on the (001) cub surface in R and M phases was found to be prominent in the forward direction rather than in the sideways direction with increasing ac electric field applied along 〈 001 〉 cub direction, providing the enhanced piezoelectric properties on (001) cub surface. On the other hand, in case of (111) cub surface in R phase, electric field-induced domain switching was found to be prominent in the sideways direction, similarly to normal ferroelectric domain switching.

Domain and Surface Structuring of LiNbO3 Single Crystal by Scanning Force Microscopy

Patterned domain structures were constructed in LiNbO3 using scanning force microscopy. The constructed structures and domain surface potential were revealed by piezoresponse force microscopy mode and Kelvin probe force microscopy mode, respectively. The clear surface-potential image could not be obtained in room air condition, but could be achieved by performing measurements after changing temperature in a vacuum. The −Z-faces of patterned domain structures were also subjected to selective chemical etching to construct surface structures with shape originating in these patterns. The surface-structure architectures can be ranged from the sub-micro to nanometer scale and hold promise for application to new functional devices.

Phase Transitions in Nanocrystalline Barium Titanate Ceramics Prepared by Spark Plasma Sintering

The bulk dense nanocrystalline BaTiO3 (BT) ceramics ranging from 20 to 100 nm have been successfully prepared by the spark plasma sintering (SPS) method. Raman spectra and X‐ray diffraction were used in combination with electron microscopy to study the evolution of lattice structure and phase transformation behavior with grain growth from nanoscale to micrometer scale for BT ceramics. The results reveal that the SPS technique provides exceptional opportunity to compact ceramics to full density with nanograin size. It is also demonstrated that all structural modifications in nanocrystalline BT and low‐symmetry structures still exist in 20 nm nanograin BT ceramics. The ferroelectric properties of crystalline structures were investigated by scanning force microscopy in piezoresponse mode. Piezoelectric hysteresis loop was recorded, demonstrating that 20 nm BT ceramics has a remanent polarization and is switchable by an electric field. Thus, if a critical grain size exists for ferroelectricity, it is less than 20 nm for polycrystalline BT ceramics.

Growth and characterization of epitaxial ferroelectric lanthanum-substituted bismuth titanate nanostructures with three different orientations

Well-ordered large-area arrays of ferroelectric La-substituted Bi4Ti3O12 (BLT) nanostructures were prepared by pulsed laser deposition using gold nanotube membranes as shadow masks. By x-ray diffraction and transmission electron microscopy, it was found that well-defined (001)-, (118)∕(100)-, and (104)-oriented BLT nanostructures were obtained on (001)-, (011)-, and (111)-oriented SrTiO3 single crystal substrates covered with epitaxial SrRuO3 electrode layers, respectively, through ex situ crystallization at 700°C. Atomic force microscopy analyses revealed that the epitaxial BLT nanostructures maintain a height of about 100nm and a lateral size of about 150nm in spite of the postannealing process. The anisotropic ferroelectric properties of the BLT nanostructures of three different orientations were investigated by scanning force microscopy in piezoresponse mode. The highest effective remanent piezoresponse coefficient (2dzz) of about 38.0pm∕V was observed in (118)∕(100)-oriented BLT nanostructures, whereas (001)- and (104)-oriented nanostructures showed smaller 2dzz values of 5.0pm∕V and 1.4pm∕V, respectively.

Direct observation of lamellar 90° and 180° domains in single grains of PZT thin film at nanoscale resolution

AbstractA ferroelectric PZT thin film with (111) orientation was prepared by a sol–gel process and deposited by spin coating on a Pt(111)/Ti/SiO2/Si wafer. The three‐dimensional (in‐plane and out‐of‐plane) domain structures were in situ visualized by using scanning force microscopy in piezoresponse mode at nanoscale resolution. Both lamellar 90° and 180° domain patterns with almost equal widths of 20–30 nm were extensively observed inside single grains. The domain distribution is a result of local mechanical stress at the interface between the grain and the substrate from periodic lattice‐constant mismatch. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Well-ordered arrays of pyramid-shaped ferroelectric BaTiO3 nanostructures

Monolayers of monodisperse latex spheres of micron size were used as deposition masks to fabricate arrays of ferroelectric nanostructures by pulsed laser deposition using a BaTiO3 target. First, arrays of well-ordered structures were prepared on SrTiO3:Nb (100) single-crystal substrates at room temperature. Investigations of these isolated as-deposited nanostructures by atomic force microscopy revealed that they have a pyramid-like shape with about 200 nm lateral size at half their height and form a regular hexagonal pattern. Then postdeposition annealing was used to crystallize the nanostructures. The ferroelectric properties of the crystalline structures were investigated by scanning force microscopy in piezoresponse mode. Piezoelectric hysteresis loops were recorded, demonstrating that the barium titanate nanopyramids have a remanent polarization and are switchable by an electric field, i.e., they are indeed ferroelectric.

Mesoscopic ferroelectric cell arrays prepared by imprint lithography

Arrays of mesoscopic ferroelectric (Pb,Zr)TiO3 cells with lateral sizes from several micrometers down to below 300 nm were prepared applying nanoimprint lithography. The ferroelectric properties of the mesoscopic cells were investigated by scanning force microscopy in piezoresponse mode. The best chemical route to obtain ferroelectric cells was found to be the sol-gel method. Using Nb-doped SrTiO3 single crystals as bottom electrodes, the crystallization into the ferroelectric phase was uniform with grain sizes in the 35 nm range.

Investigations of Mesoscopic Ferroelectric Structures Prepared by Imprint Lithography

ABSTRACTArrays of mesoscopic ferroelectric PZT structures with lateral sizes from several micrometers down to below 300 nm were prepared applying nanoimprint lithography. The ferroelectric properties of the mesoscopic structures were investigated by scanning force microscopy in piezoresponse mode. The best chemical route to obtain ferroelectric structures was found to be the sol-gel method. Using Nb-doped SrTiO3 single crystals as bottom electrodes, the crystallization into the ferroelectric phase was uniform with grain sizes in the 35 nm range. The best ferroelectric properties of individual 300 nm structures were obtained if an intermediate, continuous ferroelectric layer was present on the bottom electrode.