Data scattering in scanning tunneling spectroscopy

Severin, Nikolai; Groeper, Susie; Kniprath, Rolf; Glowatzki, H.; Koch, Norbert; Sokolov, Igor M.; Rabe, Jürgen P.

doi:10.1016/j.ultramic.2008.08.006

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…Typically, it takes about 25 ms to perform a single STS curve and the lateral drift velocity is <0.1 nm s −1 . The actual tip-sample separation for a single measurement follows a normal distribution around the mean value of the setpoint, thus the average of the data is obtained by a lognormal function to discard inappropriate data which could arise by fluctuations of the tip structure47.…”

Section: Methodsmentioning

confidence: 99%

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

2017

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Fully conjugated macrocyclic oligothiophenes exhibit a combination of highly attractive structural, optical and electronic properties, and multifunctional molecular thin film architectures thereof are envisioned. However, control over the self-assembly of such systems becomes increasingly challenging, the more complex the target structures are. Here we show a robust self-assembly based on hierarchical non-covalent interactions. A self-assembled monolayer of hydrogen-bonded trimesic acid at the interface between an organic solution and graphite provides host-sites for the epitaxial ordering of Saturn-like complexes of fullerenes with oligothiophene macrocycles in mono- and bilayers. STM tomography verifies the formation of the templated layers. Molecular dynamics simulations corroborate the conformational stability and assign the adsorption sites of the adlayers. Scanning tunnelling spectroscopy determines their rectification characteristics. Current–voltage characteristics reveal the modification of the rectifying properties of the macrocycles by the formation of donor–acceptor complexes in a densely packed all-self-assembled supramolecular nanostructure.

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Section: Methodsmentioning

confidence: 99%

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

2017

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“…A broad distribution of the STS spectra was observed on the surface regardless of the grain boundaries at room temperature (Figure 5). On the 50nm-thick LSM film, the band gap variation extended from 1.9 to 3.6eV, which goes far beyond the instrument related data dispersion (16). We tentatively attribute the broad range of band gap on LSM surface to two main mechanisms: 1) The above mentioned coexistence of the (Sr,La)O-and MnO 2 -terminated surfaces: This is consistent with topographic and spectroscopic atomic-scale study of Bi 0.24 Ca 0.76 MnO 3 , on which the phase separation into metallic and insulating surface regions was resolved in real space with STM/STS at atomic-scale resolution (17).…”

Section: Surface Electronic Properties At Ambient and Elevated Temper...mentioning

confidence: 90%

Correlations of Electronic and Chemical State on La_0.7Sr_0.3MnO₃ Dense Thin-Film Cathode Surfaces

Katsiev

Yildiz

Kavaipatti³

et al. 2009

ECS Trans.

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We report on the surface topography, electron tunneling and chemical characteristics of 10nm-and 50nm-thick La 0.7 Sr 0.3 MnO 3 (LSM) thin-films at temperatures up to 580 o C in 10-3 mbar oxygen pressure, using in situ scanning tunneling microscopy and spectroscopy (STM/STS). Coarsening of the grains was found on the 10nm-thick LSM film. High resolution mapping of the tunneling spectra onto the surface topography showed a higher electron exchange rate at select grain boundaries compared to grain surfaces. A threshold-like drop in the tunneling current was observed at positive bias in STS, and is suggested as a unique indicator to the activation polarization in cation-oxygen bonding on LSM. Sr-enrichment and Mn-depletion were found on the surface at high temperature using Auger electron spectroscopy, accompanied by a reduction in tunneling conductance in STS. This suggests that the Mn-terminated surfaces are more active for electron exchange in oxygen reduction compared to the (La,Sr)terminated surfaces on LSM.

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“…The average of the I – V curves is obtained by taking the normal logarithm of the current to discard inappropriate data which could arise by fluctuations of the tip structure. [ 64 ] In Figures S3c and S4b (Supporting Information), the error lines are one standard deviation above and below the average value. All plotting and analysis were conducted with Origin 9.0.…”

Section: Methodsmentioning

confidence: 99%

Resonant Electron Tunneling Induces Isomerization of π‐Expanded Oligothiophene Macrocycles in a 2D Crystal

2022

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Dedicated to Professor Klaus Müllen on the occasion of his 75th birthdayMacrocyclic oligothiophenes and their 𝝅-expanded derivatives constitute versatile building blocks for the design of (supra)molecularly engineered active interfaces, owing to their structural, chemical, and optoelectronic properties. Here, it is demonstrated how resonant tunneling effect induces single molecular isomerization in a 2D crystal, self-assembled at solid-liquid interfaces under ambient conditions. Monolayers of a series of four 𝝅-expanded oligothiophene macrocycles are investigated by means of scanning tunneling microscopy and scanning tunneling spectroscopy (STS) at the interface between their octanoic acid solutions and the basal plane of highly oriented pyrolytic graphite. Current-voltage characteristics confirm the donor-type character of the macrocycles, with the highest occupied molecular orbital and the lowest unoccupied molecular orbital (LUMO) positions consistent with time-dependent density functional theory calculations. Cyclic STS measurements show the redox isomerization from Z,Z-8T6A to its isomer E,E-8T6A occurring in the 2D crystal, due to the formation of a negatively charged species when the tunneling current is in resonance with the LUMO of the macrocycle.

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Data scattering in scanning tunneling spectroscopy

Cited by 3 publications

References 15 publications

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

Correlations of Electronic and Chemical State on La_0.7Sr_0.3MnO₃ Dense Thin-Film Cathode Surfaces

Resonant Electron Tunneling Induces Isomerization of π‐Expanded Oligothiophene Macrocycles in a 2D Crystal

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Data scattering in scanning tunneling spectroscopy

Cited by 3 publications

References 15 publications

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

Templated bilayer self-assembly of fully conjugated π-expanded macrocyclic oligothiophenes complexed with fullerenes

Correlations of Electronic and Chemical State on La0.7Sr0.3MnO3 Dense Thin-Film Cathode Surfaces

Resonant Electron Tunneling Induces Isomerization of π‐Expanded Oligothiophene Macrocycles in a 2D Crystal

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Correlations of Electronic and Chemical State on La_0.7Sr_0.3MnO₃ Dense Thin-Film Cathode Surfaces