Tag Archives: Platinum Silicide AFM probes

Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures

Nanoscale investigations by scanning probe microscopy have provided major contributions to the rapid development of organic–inorganic halide perovskites (OIHP) as optoelectronic devices. Further improvement of device level properties requires a deeper understanding of the performance-limiting mechanisms such as ion migration, phase segregation, and their effects on charge extraction both at the nano- and macroscale.*

In the article “Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures” David Toth, Bekele Hailegnaw, Filipe Richheimer, Fernando A. Castro, Ferry Kienberger, Markus C. Scharber, Sebastian Wood and Georg Gramse describe how they studied the dynamic electrical response of Cs0.05(FA0.83MA0.17)0.95PbI3–xBrx perovskite structures by employing conventional and microsecond time-resolved open-loop Kelvin probe force microscopy (KPFM).*

Their results indicate strong negative charge carrier trapping upon illumination and very slow (>1 s) relaxation of charges at the grain boundaries. The fast electronic recombination and transport dynamics on the microsecond scale probed by time-resolved open-loop KPFM show diffusion of charge carriers toward grain boundaries and indicate locally higher recombination rates because of intrinsic compositional heterogeneity. The nanoscale electrostatic effects revealed are summarized in a collective model for mixed-halide CsFAMA. Results on multilayer solar cell structures draw direct relations between nanoscale ionic transport, charge accumulation, recombination properties, and the final device performance.*

The author’s findings extend the current understanding of complex charge carrier dynamics in stable multication OIHP structures.*

NANOSENSORS™ Platinum Silicide AFM Probes of the PtSi-CONT type (nominal resonance frequency 13 kHz, nominal force constant 0.2 N/m) were used for the measurements described in the research article cited above. *

Figure 3. from “Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures” by David Toth et al:
Initial dark and relaxed closed-loop KPFM analysis of CsFAMAPbBrI. (a) Topography channel plotting surface height. (b) KPFM image prior to light pulse plotting Vcpd. (c) KPFM image seconds after the light pulse plotting Vcpd. (d) 3D topography overlaid with the calculated ΔVcpd map. (e) Histograms of before and after Vcpd maps separated into grain and GB responses. The double arrows indicate the difference between the mean values of the distributions. NANOSENSORS™ Platinumum-Silicide PtSi-CONT AFM probes were used for the KPFM measurements.

Figure 3. from “Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures” by David Toth et al:
Initial dark and relaxed closed-loop KPFM analysis of CsFAMAPbBrI. (a) Topography channel plotting surface height. (b) KPFM image prior to light pulse plotting Vcpd. (c) KPFM image seconds after the light pulse plotting Vcpd. (d) 3D topography overlaid with the calculated ΔVcpd map. (e) Histograms of before and after Vcpd maps separated into grain and GB responses. The double arrows indicate the difference between the mean values of the distributions.

*David Toth, Bekele Hailegnaw, Filipe Richheimer, Fernando A. Castro, Ferry Kienberger, Markus C. Scharber, Sebastian Wood and Georg Gramse
Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures
ACS Appl. Mater. Interfaces 2020, 12, 42, 48057–48066
DOI: https://doi.org/10.1021/acsami.0c10641

Please follow this external link to read the full article: https://pubs.acs.org/doi/abs/10.1021/acsami.0c10641

Open Access The article “Nanoscale Charge Accumulation and Its Effect on Carrier Dynamics in Tri-cation Perovskite Structures” by David Toth, Bekele Hailegnaw, Filipe Richheimer, Fernando A. Castro, Ferry Kienberger, Markus C. Scharber, Sebastian Wood and Georg Gramse is licensed under a ACS AuthorChoice  – Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Further permissions related to the material excerpted above should be directed to the ACS .

Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host

In the article “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki report a magnetic state in GaV4Se8 which emerges exclusively in samples with mesoscale polar domains and not in polar mono-domain crystals.*

It is manifested by a sharp anomaly in the magnetic susceptibility and the magnetic torque, distinct from other anomalies observed also in polar mono-domain samples upon transitions between the cycloidal, the Néel-type skyrmion lattice and the ferromagnetic states. *

The authors ascribe this additional transition to the transformation of distinct magnetic textures, confined to polar domain walls (DW), to the ferromagnetic (FM) state. The emergence of these DW-confined magnetic states is likely driven by the mismatch of different spin spirals, hosted by the adjacent domains. A clear anomaly in the magneto-current indicates that the DW-confined magnetic states also have strong contributions to the magnetoelectric response. *

The authors expect polar DWs to commonly host such confined magnetic edge states and, thus, offer a fertile ground to explore novel forms of magnetism. *

To characterize the polar domains and to estimate the density of DWs in GaV4Se8, K. Geirhos et al. combined several complementary scanning probe microscopy techniques, including non-contact atomic force microscopy ( nc-AFM ), scanning dissipation microscopy ( SDM ), and frequency-modulated Kelvin-probe force microscopy ( KPFM ). *

In attempt to observe spin cycloidal and Néel-type skyrmion textures within polar domains of GaV4Se8, only evidenced by small-angle neutron scattering measurements so far43, the authors of the article also carried out magnetic force microscopy (MFM) measurements. A second purpose of the MFM study was to explore possible magnetic states confined to the vicinity of DWs, as reported in GaV4S8. *

NANOSENSORS™ SSS-QMFMR high resolution magnetic AFM probes for ultra high vacuum conditions were used for the magnetic measurements with scanning probe microscopy. *

NANOSENSORS™ conductive wear-resistant Platinum Silicide AFM probes of the PtSi-FM type were used for all other measurements described in the article. *

Supplementary Figure 1 a – d from “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by K. Geirhos et al:

Typical ferroelectric do-main pattern observed on the (001) cleaved GaV4Se8 crystal surface  atT=10  K.
a, The topography is characterized by stripes roughly parallel to the [110] axis and folds parallel to the [010]  axis. The latter originate in the differently oriented distortion of the ferroelastic domains. The color scale corresponds to the z-displacement of the tip.
b ,In the dissipation channel of the nc-AFM every second domain appears bright. For the non-magnetic tip the dissipation originates from electric interactions. The dissipated power is indicated by the color scale. Please have a look at the full article to view the full supplementary figure.
NANOSENSORS Platinum Silicide PtSi-FM AFM probes were used for the imaging.
Supplementary Figure 1 a – d from “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by K. Geirhos et al:

Typical ferroelectric do-main pattern observed on the (001) cleaved GaV4Se8 crystal surface  atT=10  K.
a, The topography is characterized by stripes roughly parallel to the [110] axis and folds parallel to the [010]  axis. The latter originate in the differently oriented distortion of the ferroelastic domains. The color scale corresponds to the z-displacement of the tip.
b ,In the dissipation channel of the nc-AFM every second domain appears bright. For the non-magnetic tip the dissipation originates from electric interactions. The dissipated power is indicated by the color scale. Please have a look at the full article to view the full supplementary figure.

*Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki
Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host
npj Quantum Materials volume 5, Article number: 44 (2020)
DOI: https://doi.org/10.1038/s41535-020-0247-z

Please follow this external link to read the full article: https://rdcu.be/b7lgW

Open Access The article “Macroscopic manifestation of domain-wall magnetism and magnetoelectric effect in a Néel-type skyrmion host” by Korbinian Geirhos, Boris Gross, Bertalan G. Szigeti, Andrea Mehlin, Simon Philipp, Jonathan S. White, Robert Cubitt, Sebastian Widmann, Somnath Ghara, Peter Lunkenheimer, Vladimir Tsurkan, Erik Neuber, Dmytro Ivaneyko, Peter Milde, Lukas M. Eng, Andrey O. Leonov, Sándor Bordács, Martino Poggio and István Kézsmárki is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric Ca3Ti2O7

Ferroic materials are well known to exhibit heterogeneity in the form of domain walls. Understanding the properties of these boundaries is crucial for controlling functionality with external stimuli and for realizing their potential for ultra-low power memory and logic devices as well as novel computing architectures.*

In the article “Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric Ca3Ti2O7” K. A. Smith, E. A. Nowadnick, S. Fan, O. Khatib, S. J. Lim, B. Gao, N. C. Harms, S. N. Neal, J. K. Kirkland, M. C. Martin, C. J. Won, M. B. Raschke, S.-W. Cheong, C. J. Fennie, G. L. Carr, H. A. Bechtel and J. L. Musfeldt employ synchrotron-based near-field infrared nano-spectroscopy to reveal the vibrational properties of ferroelastic (90∘ ferroelectric) domain walls in the hybrid improper ferroelectric Ca3Ti2O7 . By locally mapping the Ti-O stretching and Ti-O-Ti bending modes, they reveal how structural order parameters rotate across a wall. Thus, they link observed near-field amplitude changes to underlying structural modulations and test ferroelectric switching models against real space measurements of local structure. This initiative opens the door to broadband infrared nano-imaging of heterogeneity in ferroics.*

NANOSENSORS™ Platinum Silicide PtSi-NCH AFM probes were used for the Near-field infrared spectroscopy. Atomic force and piezoforce imaging reveal the different orientations of directional order parameters and domain wall character, providing a physical playground for graph theory. *

Fig. 2 from: «Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric Ca3Ti2O7» K. A. Smith et al. 2019
Combining scanning techniques to locate domain walls. a, b Atomic force microscopic (AFM) images of the crystal surfaces showing the two ferroelastic domain walls of interest (at the edges of the dark blue stripes). These ferroelastic walls separate domains of different spontaneous strain and are also 90∘ ferroelectric walls. DW 1 and DW 2 refer to domain walls 1 and 2. Red arrows indicate direction and path of the line scans. The nano-spectroscopic line scans are taken perpendicular to the wall, and the contact angle from one domain to another is 90∘. c AFM topography of a smooth area near an identified surface defect (indicated by a green circle) and step edge of approximately 100 nm height (indicated with a red arrow) compared with d the piezoresponse force microscopic (PFM) image of the same area revealing the placement and orientation of the 180∘ ferroelectric domains, indicated by yellow(+) or blue(−) regions with black or white arrows to indicate the polarization direction. All of these structures are present at room temperature

*K. A. Smith, E. A. Nowadnick, S. Fan, O. Khatib, S. J. Lim, B. Gao, N. C. Harms, S. N. Neal, J. K. Kirkland, M. C. Martin, C. J. Won, M. B. Raschke, S.-W. Cheong, C. J. Fennie, G. L. Carr, H. A. Bechtel and J. L. Musfeldt
Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric Ca3Ti2O7
Nature Communications volume 10, Article number: 5235 (2019)
DOI: https://doi.org/10.1038/s41467-019-13066-9

Please follow this external link to read the full article: https://rdcu.be/b2rPq

Open Access: The article “Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric Ca3Ti2O7” by K. A. Smith, E. A. Nowadnick, S. Fan, O. Khatib, S. J. Lim, B. Gao, N. C. Harms, S. N. Neal, J. K. Kirkland, M. C. Martin, C. J. Won, M. B. Raschke, S.-W. Cheong, C. J. Fennie, G. L. Carr, H. A. Bechtel and J. L. Musfeldt is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.