Unveiling the nature of atomic defects in graphene on a metal surface

• Karl Rothe,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2024, 15, 416–425, doi:10.3762/bjnano.15.37

• , 5 min). The Ar+ beam enclosed an angle of 15° with the surface normal and exhibited a flux of ≈0.01 1/(nm2·s). A chemically etched (NaOH, 0.1 M) W wire (purity: 99.99%, diameter: 50 μm) was used as the tip material. Tips were cleaned by field emission on and indentations into a clean Au(111) crystal

Two-dimensional molecular networks at the solid/liquid interface and the role of alkyl chains in their building blocks

• Suyi Liu,
• Yasuo Norikane and
• Yoshihiro Kikkawa

Beilstein J. Nanotechnol. 2023, 14, 872–892, doi:10.3762/bjnano.14.72

• structures on metallic surfaces, such as Au(111), are different from those on a HOPG surface, even if the molecular building blocks are the same [62][63][64]. This is because of the different molecule–substrate interactions on Au(111) and HOPG. The adsorption energy of alkyl chains on Au(111) has been

• reported as −1.48 kcal/mol per CH2 unit [65], whereas that on HOPG is approximately −1.9 kcal/mol per CH2 unit [47][56], as noted above. The periodicity of alkyl chains almost matches HOPG lattice, but does not Au(111) lattice, on which the alkyl chains favor to align along the nearest neighbor direction

• [66]. These differences in the dispersion interaction may be one of the causes of 2D structural changes between Au(111) and HOPG surfaces [67]. In the following sections, the effect of alkyl chains on 2D structure formations are summarized only for the HOPG surface. 2 Missing alkyl chains Although the

Molecular nanoarchitectonics: unification of nanotechnology and molecular/materials science

• Katsuhiko Ariga

Beilstein J. Nanotechnol. 2023, 14, 434–453, doi:10.3762/bjnano.14.35

• multistep electrochemical epitaxial polymerization technique [113]. This technique consists of combining two electrochemical polymerization processes using different monomer solutions. First, a voltage pulse was applied to an iodine-covered Au(111) substrate in an electrolyte solution containing the first

• . Foster, Kawai, and co-workers have investigated the zero-bias peak at the center of an armchair-type graphene nanoribbon on a AuSix/Au(111) surface using a combination of low-temperature scanning tunneling microscopy/spectroscopy and density functional theory calculations [116]. The zero-bias peak at the

• ) backbones (Figure 7) [120]. First, silicon atoms were deposited on a Au(111) surface and annealed to form an AuSix film. Bromo-substituted polycyclic hydrocarbon precursors (triphenylene or pyrene) were then deposited on this surface and annealed to form a C4Si2 bridging network. In the linear structures

Design of surface nanostructures for chirality sensing based on quartz crystal microbalance

• Yinglin Ma,
• Xiangyun Xiao and
• Qingmin Ji

Beilstein J. Nanotechnol. 2022, 13, 1201–1219, doi:10.3762/bjnano.13.100

• deposited CuO film onto highly symmetrical Au(111) surfaces was shown to have mirror-symmetric chirality. The enantiospecificity of the films was studied using QCM and evaluated according to the changes by the selective oxidation of chiral tartaric acid. The films etched in ʟ-(+)-tartaric acid were shown to

• successfully controlled the long-range chirality recognition of 3-bromonaphthalen-2-ol (BNOL) on a Au(111) surface and proved the recognition force from the herringbone reconstruction-induced accumulation of dipoles at the stripe edge of BNOL [140]. Liu and Li et al. studied the enantiospecific adsorption of α

A cantilever-based, ultrahigh-vacuum, low-temperature scanning probe instrument for multidimensional scanning force microscopy

• Hao Liu,
• Zuned Ahmed,
• Sasa Vranjkovic,
• Manfred Parschau,
• Andrada-Oana Mandru and
• Hans J. Hug

Beilstein J. Nanotechnol. 2022, 13, 1120–1140, doi:10.3762/bjnano.13.95

• . Clearly, the deflection sensor noise does no longer limit the minimally detectable force derivative for bandwidths up to and beyond 1 kHz. Such high measurement bandwidths can for example, be used to measure with high speed a large-scale image showing atomic steps of the Au(111) surface with thin NaCl

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• Abstract Ultrathin membranes with subnanometer pores enabling molecular size-selective separation were generated on surfaces via electron-induced cross-linking of self-assembled monolayers (SAMs). The evolution of p-terphenylthiol (TPT) SAMs on Au(111) surfaces into cross-linked monolayers was observed

• structural changes is still lacking. In this work, we investigated the structural changes occurring upon irradiation of SAMs of p-terphenylthiol (TPT) on Au(111) using a combination of scanning electron microscopy (SEM) and scanning tunneling microscopy in ultrahigh vacuum (UHV) at room temperature. To study

• general concept of self-assembly allows for the preparation of SAMs from the liquid or gas phase. Highly ordered TPT SAMs spontaneously form on Au(111) due to the formation of bonds between sulfur and gold atoms, which is accompanied by van der Waals interactions between the aromatic rings. The TPT SAMs

Impact of device design on the electronic and optoelectronic properties of integrated Ru-terpyridine complexes

• Max Mennicken,
• Sophia Katharina Peter,
• Corinna Kaulen,
• Ulrich Simon and
• Silvia Karthäuser

Beilstein J. Nanotechnol. 2022, 13, 219–229, doi:10.3762/bjnano.13.16

• -SAc)–AuNPs, with an average size of 12.9 ± 1.6 nm (Supporting Information File 1, Figure S2). Ru(TP)2-complex wire growth For the tracking of the Ru(TP)2-complex wire formation via XPS measurements mica substrates of 8 × 4 mm2 covered by a 200 nm Au(111) layer were used. In a first step the substrates

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• method can yield single isolated molecules accompanied by surface modifications. Keywords: alkali halide; Au(111); bulk insulator; C60; electrospray; electrospray deposition; fullerene; high-vacuum electrospray deposition (HV-ESD); molecular assembly; nc-AFM; NiO; single molecule; thermal evaporation

• microscope (nc-AFM) working at room temperature to study formation and shape of C60 islands on three substrates with different intrinsic properties. These are, first, Au(111), a metal surface widely used in SPM studies, second, KBr(001), a bulk insulator allowing for the decoupling of molecular species and

• us to discuss the influence of the HV-ESD method for the different surfaces. Results and Discussion C60 on Au(111) The deposition of C60 molecules on a Au(111) surface at room temperature via TE is known to lead to the formation of monolayer islands until the surface is fully covered [21][25][28]. A

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• PTCDA from Cu(111). For PTCDA on Ag(111) and Au(111) [39], it has been shown that FL can only be observed from the second and third molecular layer onward. The excitation of the first layers is completely quenched by the metal substrates as described above. In UPS experiments, a partial filling of the

• LUMO of PTCDA was found on Ag(111), but not on Au(111) [33]. Thus, the quenching on Ag(111) is directly understood by the static charge transfer seen in UPS. The quenching on Au(111), not as evident from UPS, demonstrates the sensitivity of FL spectroscopy to an overlap of wave functions of excited

• , we mention a recent study by Stallberg et al. [39], which investigated optical spectra of PTCDA on Ag(111) and Au(111). They found Raman modes of PTCDA on the Au(111) surface, but not on the Ag(111) surface. This observation was discussed in view of the different energies of the SPPs of the two

Adsorption and self-assembly of porphyrins on ultrathin CoO films on Ir(100)

• Feifei Xiang,
• Tobias Schmitt,
• Marco Raschmann and
• M. Alexander Schneider

Beilstein J. Nanotechnol. 2020, 11, 1516–1524, doi:10.3762/bjnano.11.134

• homogeneous contrast develops in Figure 4d. Such compact assemblies were previously observed for the case of the non-metalated 2H-DPP compound on Ag(110) [24] and on Au(111) [22], but, for example, not on Cu(111) [23]. For the assembly on 1BL CoO, the distance between the phenyl rings is a little larger than

Impact of fluorination on interface energetics and growth of pentacene on Ag(111)

• Qi Wang,
• Meng-Ting Chen,
• Antoni Franco-Cañellas,
• Bin Shen,
• Thomas Geiger,
• Holger F. Bettinger,
• Frank Schreiber,
• Ingo Salzmann,
• Alexander Gerlach and
• Steffen Duhm

Beilstein J. Nanotechnol. 2020, 11, 1361–1370, doi:10.3762/bjnano.11.120

• contribution polarization [11][44]. Perfluorination does not impact the orientation of PEN and PFP in the contact layer with clean metals, where both compounds are lying flat [9][30][31][47][48][49][50][51][52]. On Au(111), the coupling strength of both monolayers with the substrate is rather similar and

• physisorptive [29][53]. On Cu(111), PFP shows a behavior close to physisorption [9], although the coupling strength might be slightly stronger than with Au(111) [54]. PEN on Cu(111), however, is strongly chemisorbed, involving a partial filling of the former lowest unoccupied molecular orbital (LUMO) by a

• fluorinated PEN, namely 2,3,9,10-tetrafluoropentacene (F4PEN) [46][60][61]. F4PEN physisorbs on Au(111) [62] and chemisorbs on Cu(111), involving interfacial charge transfer and strong molecular distortions [63]. Here, we investigated the coupling with Ag(111) as we expected this to be an interesting

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• conductive surface, large and constant additional currents relative to a set tunneling current were observed, which varied with the magnitude of the applied bias voltage. These currents occurred regardless of the type of surface (HOPG or Au(111)) or tip material (PtIr, Au or W). The additional currents were

• at room temperature. We found that while the porphyrin catalyst MnTUPCl (tetrakis-meso-undecylporphyrin manganese(III) chloride, Figure 1a) is fully inert in n-tetradecane solution, it becomes catalytically active in the epoxidation of alkenes when it is adsorbed at the interface of a Au(111

• fate of this ligand is. In the catalysis study with MnTUPCl at the Au(111) surface, two possible mechanisms were proposed [7]: (i) A surface gold atom coordinates to the manganese center of MnTUPCl in an axial ligand-like fashion, inducing a chlorine radical to dissociate, thereby reducing the Mn(III

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• ordered DBP on h-BN/Ni(111), suitable coincidences with the lowest substrate orders are the on-line coincidences (1, 2), (−1, −2), (−2, 1), and (2, −1). A comparison with reported lateral structures of DBP on Ag(111) [34] and Au(111) [33] shows very similar adsorbate lattice parameters except for the unit

• the LT-STM measurements, we concluded that the DBP molecules adopt a herringbone structure similar to DBP on Ag(111) and Au(111). Furthermore, we observed that the low work function of h-BN/Ni(111) decreases upon DBP deposition down to a value of 3.45(2) eV for the highly ordered DBP layer on h-BN/Ni

• the lattice parameters obtained by our LEED analysis with reference data of DBP on Au(111) (1 MLE) [33] and on Ag(111) (1.3 MLE) [34]. The angle Γ is defined between the lattice vectors of the adsorbate and . The angle between the adsorbate lattice vector and the direction of the substrate lattice

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• Karl Rothe Alexander Mehler Nicolas Neel Jorg Kroger Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany 10.3762/bjnano.11.100 Abstract Rubrene (C42H28) was adsorbed with submonolayer coverage on Pt(111), Au(111), and graphene-covered Pt(111). Adsorption phases and

• vibronic properties of C42H28 consistently reflect the progressive reduction of the molecule–substrate hybridization. Separate C42H28 clusters are observed on Pt(111) as well as broad molecular resonances. On Au(111) and graphene-covered Pt(111) compact molecular islands with similar unit cells of the

• superstructure characterize the adsorption phase. The highest occupied molecular orbital of C42H28 on Au(111) exhibits weak vibronic progression while unoccupied molecular resonances appear with a broad line shape. In contrast, vibronic subbands are present for both frontier orbitals of C42H28 on graphene. They

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• of decoupling layers made use of the in situ fabrication of single layers of transition metal dichalcogenides on metal surfaces. A monolayer of MoS2 on Au(111) provided very narrow molecular resonances, close to the thermal resolution limit at 4.6 K [26]. The exquisite decoupling efficiency has been

• nature of the substrate [33]. One may thus envision tuning the bandgap alignment for decoupling either the lowest unoccupied (LUMO) or the highest occupied molecular orbital (HOMO) of the molecules. While MoS2 on Au(111) has already been established as an outstanding decoupling layer [26], we will now

• explore this potential for MoS2 on a Ag(111) surface. In agreement with the band modifications of WS2 on Au(111) and Ag(111), we find that the bandgap remains almost the same, albeit shifted to lower energies [33]. As a test molecule we chose tetracyanoquinodimethane (TCNQ). Due to its electron-accepting

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• between Sn-up and Sn-down was also reported on Cu(111) and Ag(100), while this reaction did not occur on Au(111) and Au(110) surfaces [28]. On the Ag(111) surface, within the first layer, Sn-up molecules were irreversibly switched to the down position, while on InAs(111), the molecules could be switched

Templating effect of single-layer graphene supported by an insulating substrate on the molecular orientation of lead phthalocyanine

• K. Priya Madhuri,
• Abhay A. Sagade,
• Pralay K. Santra and
• Neena S. John

Beilstein J. Nanotechnol. 2020, 11, 814–820, doi:10.3762/bjnano.11.66

• (111), Si and SiO2. Detailed studies using Raman spectroscopy and 2D-GIXRD show ordered monoclinic and triclinic moieties on HOPG and Si substrates, respectively, while the Au(111) surface gives rise to disordered fractions due to the absence of long-range ordering [9][26]. In the present study, the

• orientation of both planar and nonplanar MPc molecules on oxide substrates such as SiO2 is well known. The molecules were shown to preferably have an edge-on orientation [3][7][9][27][28][29]. In our earlier studies, we have reproducibly obtained different crystallites of PbPc on substrates such as HOPG, Au

Antimony deposition onto Au(111) and insertion of Mg

• Lingxing Zan,
• Da Xing,
• Abdelaziz Ali Abd-El-Latif and
• Helmut Baltruschat

Beilstein J. Nanotechnol. 2019, 10, 2541–2552, doi:10.3762/bjnano.10.245

• processes are kinetically slow because of the large ionic radius and high charge density of Mg2+ compared with Li+. In this work, we prepared very thin films of Sb by electrodeposition on a Au(111) substrate. Monolayer and multilayer deposition (up to 20 monolayers) were characterized by cyclic voltammetry

• : alloy; antimony; Au(111); electrodeposition; insertion; STM; Introduction Rechargeable batteries have become essential energy storing devices, which are widely used in portable electronic devices and hybrid electric vehicles. Magnesium-based secondary batteries have been regarded as a viable

• deposition on a Au electrode was carried out by Jung [8], who found that antimony deposition on Au(100) and Au(111) in acid electrolyte undergoes two electrochemical processes involving an irreversible adsorption and underpotential deposition. This irreversible adsorption was attributed to oxygenous Sb(III

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• characteristics of differently shaped islands within a PAT SAM, first PAT-layers were deposited on the Au(111) surface by immersing Au substrates into ethanol solution of PAT protected with a thioester group. Deposition was carried out at 70 °C. At this elevated temperature the thioester protective group was

• of the orientation of the spacer group [26]. In a next step, STM images were recorded that demonstrate SAM formation of PAT on an atomically smooth Au(111) surface. As shown in the control STM data (Supporting Information File 1, Figure S3), the initially distributed smaller nucleation centers with a

Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower

• Rouzhaji Tuerhong,
• Mauro Boero and
• Jean-Pierre Bucher

Beilstein J. Nanotechnol. 2019, 10, 1243–1250, doi:10.3762/bjnano.10.124

• Discussion Molecule transfer and imaging Figure 1a shows a topographic STM image of MnPc molecules on Au(111) taken with a Au-covered W tip. As seen clearly from the STM image, the MnPc molecules adsorb face-on. The bright protrusion at the center of MnPc is due to the Mn d-orbital states near the Fermi

• level [21]. By approaching the STM tip towards a molecule on the Au(111) surface, it is possible to transfer a single MnPc molecule from the surface to the tip apex of the STM. Then the presence of a molecule on the tip can be directly confirmed by the reverse transfer process, i.e., by applying a

• , the MnPc molecule has been only partially lifted from the surface as anticipated from the STM image of Figure 2d and indicated schematically in Figure 2f (see below). Because the molecule–tip interaction is stronger than the molecule–surface interaction, it is possible to scan the bare Au(111) surface

Pure and mixed ordered monolayers of tetracyano-2,6-naphthoquinodimethane and hexathiapentacene on the Ag(100) surface

• Robert Harbers,
• Timo Heepenstrick,
• Dmitrii F. Perepichka and
• Moritz Sokolowski

Beilstein J. Nanotechnol. 2019, 10, 1188–1199, doi:10.3762/bjnano.10.118

• constituents of CT crystals thus form a specific subset. We name a few examples. On the Au(111) surface, ordered monolayers were observed for following donor/acceptor pairs: tetrathiafulvalene (TTF)/7,7,8,8-tetracyanoquinodimethane (TCNQ) [11][12], tetramethyltetrathiafulvalene (TMTTF)/TCNQ [13], α

• combination with tetrathiafulvalene (TTF) on Au(111). TNAP is a flat planar molecule (C2h) with the ability to delocalize unpaired electrons in a charge-transfer complex [26]. We note that the crystal structure of TNAP is unknown and, as a consequence, we cannot compare the packing of TNAP on the Ag(100

• the frontier orbitals of the respective molecules we refer to Supporting Information File 1.) Accordingly, in the gas phase one does not expect spontaneous electron transfer from HTPEN to TNAP. This in contrast to the previously studied situation for the TTT/TNAP mixed structure on the Au(111) surface

The effect of translation on the binding energy for transition-metal porphyrines adsorbed on Ag(111) surface

• Luiza Buimaga-Iarinca and
• Cristian Morari

Beilstein J. Nanotechnol. 2019, 10, 706–717, doi:10.3762/bjnano.10.70

• . This is a consequence of the fact that self-organization is dominated by the periphery of the porphyrin [32][33][34][35][36][37][38]. As an example, we note the case of mixtures of Co-TPP and Ni-TPP (TPP = tetraphenylporphyrin) on Au(111) forming ordered islands with random distributions of the two

• that Kondo effect of organo-metallic compounds adsorbed on coinage metals is sensitive to the manipulation of the chemical bonds [73][74]. The Kondo effect in Co-porphyrins on Au(111) can be switched on or off by binding a NO group to the molecule [73]. Also, the changes in molecular conformation can

Intuitive human interface to a scanning tunnelling microscope: observation of parity oscillations for a single atomic chain

• Sumit Tewari,
• Jacob Bakermans,
• Christian Wagner,
• Federica Galli and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2019, 10, 337–348, doi:10.3762/bjnano.10.33

• this system is demonstrated by preparing and lifting a monoatomic chain of gold atoms from a Au(111) surface in a well-controlled manner. We have demonstrated the existence of Fabry–Pérot-type electronic oscillations in such a monoatomic chain of gold atoms and determined its phase, which was difficult

• annealing cycles to obtain an atomically flat Au(111) facet showing herringbone surface reconstruction. We further prepare the surface at low temperature by creating a localized stress pattern [11][12][13][14] on the surface using gentle indentation of the STM tip at a spot on the surface remote from the

• area of investigation. This creates new crystalline (111) facets and provides straight step edges in the three crystallographic directions of Au(111) (i.e., , and ) as shown in Figure 2a. Additional gold atoms (adatoms) are deposited [15][16][17][18] on the Au(111) surface at the target sites of

Nitrous oxide as an effective AFM tip functionalization: a comparative study

• Taras Chutora,
• Bruno de la Torre,
• Pingo Mutombo,
• Jack Hellerstedt,
• Jaromír Kopeček,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2019, 10, 315–321, doi:10.3762/bjnano.10.30

• Physics of the Czech Academy of Sciences, Cukrovarnická 10, 162 00 Prague, Czech Republic 10.3762/bjnano.10.30 Abstract We investigate the possibility of functionalizing Au tips by N2O molecules deposited on a Au(111) surface and their further use for imaging with submolecular resolution. First, we

• characterize the adsorption of the N2O species on Au(111) by means of atomic force microscopy with CO-functionalized tips and density functional theory (DFT) simulations. Subsequently we devise a method of attaching a single N2O to a metal tip apex and benchmark its high-resolution imaging and spectroscopic

• apexes. Keywords: atomic force microscopy; Au(111); carbon monoxide; functionalization; high resolution; nitrous oxide; submolecular resolution; Introduction Frequency-modulated atomic force microscopy (AFM) has become the tool of choice for the characterization of molecules on the atomic scale

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• are prepared in deionized water. Target molecules are absorbed on Au(111) flat films that have undergone standard flame annealing in order to obtain crystalline terraces of about 100 nm in size. The gold film substrates are immersed for 2 h and 30 min and subsequently rinsed in deionized water in

• resolution in TERS imaging Nanoscale resolution is shown in simultaneous morphological (STM) and chemical (TERS) mapping of R6G molecules (10−4 M) absorbed on Au(111). Experiments are carried out in gap-mode, with excitation at 638 nm. Figure 9a shows the STM topography acquired on a 300 × 300 nm2 area with

• bound) in gap-mode. TERS maps of sub-monolayer films of R6G on Au(111) are shown with optical resolution better than 5 nm. The procedure can in principle be applied to thinner wires to further reduce costs and production times, although issues related to the fragility of the tip and difficulties in the