Observation of Large-Scale Features on Graphite by Scanning Tunnelling Microscopy

Pong, Wing-Tat; Bendall, James S.; Durkan, Colm

doi:10.1143/jjap.44.5443

Cited by 10 publications

(14 citation statements)

References 12 publications

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“…Another large-scale feature on graphite, related to superlattices and which has been reported recently [43], is that of one-dimensional fringes with periodicities of 20 and 30 nm and corrugations of 0.1 and 0.15 nm which have been observed on a superlattice (figures 2 and 3). The fringes were observed under differing tunnelling conditions as shown in figures 2(c) and (e).…”

Section: Large-scale Features Observed On Graphite Under Stmsupporting

confidence: 52%

“…Tunnelling conditions overlayers factor [37] V tip = 20 mV, I t = 0.8 nA 1 2.6 [37] V tip = 180 mV, I t = 0.9 nA 1 2.3 [37] V tip = 15 mV, I t = 0.8 nA 1 2.6 [37] V tip = 180 mV, I t = 0.9 nA 1 1.6 a [72] (not provided) 1 2 b [72] (not provided) 2 4 b [43] V s = 206 mV, I t = 0.5 nA 1 2.3 [21] V tip = 178 mV, I t = 2.4 nA 2 5 [48] V s = 100 mV, I t = 1.0 nA 1 2.4 [47] V tip = 150 mV 1 1.59 [70] V s = 1200 mV 1 2.15 a This is the AF for the bead-like boundary of the superlattice covered by one overlayer. b The authors of [72] observed the superlattices covered by one and two graphite sheets, and from these data, they proposed equation (15), however, without mentioning explicitly the AFs that they observed experimentally for one and two overlayers.…”

Section: Number Of Attenuation Of Datamentioning

confidence: 99%

“…The rippling fringes on graphite from[43]. (a) 700 nm × 500 nm image (I t = 0.36 nA, V s = 450 mV) on graphite with the central part being the superlattice as shown by the inset.…”

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confidence: 99%

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A review and outlook for an anomaly of scanning tunnelling microscopy (STM): superlattices on graphite

Pong

Durkan²

2005

J. Phys. D: Appl. Phys.

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159

127

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Since its invention in 1981, scanning tunnelling microscopy (STM) is well-known for its supreme imaging resolution enabling one to observe atomic-scale structures, which has led to the flourishing of nanoscience. As successful as it is, there still remain phenomena which are observed using STM but are beyond our understanding. Graphite is one of the surfaces which have been most extensively studied using STM. However, there are a number of unusual properties of graphite surfaces. First reported in the 1980s, superlattices on graphite have since been observed many times and by many groups, but as yet our understanding of this phenomenon is quite limited. Most of the observed superlattice phenomena are widely believed to be the result of a Moiré rotation pattern, arising from the misorientation between two graphite layers, as verified experimentally. A Moiré pattern is a lattice with larger periodicity resulting from the overlap of two lattices with smaller periodicities. As graphite layers are composed of hexagonal lattices with a periodicity of 0.246 nm, as observed using STM, when there are misoriented graphite layers overlapping each other, a Moiré pattern with larger periodicity, depending on the misorientation angle, will be produced and appear as a superperiodic hexagonal structure on top of the graphite atomic lattice of the topmost surface layer. It is important to study graphite superlattices because, firstly, knowledge of this phenomenon will enable us to properly interpret STM images; secondly, it helps us to understand the correlation between electronic structures and atomic-structure rearrangement of graphite which is of tremendous aid for engineering material properties; thirdly, and perhaps most importantly, the observation of the phenomenon exhibits the capability of STM to produce images indicating the nature of internal defects which are below the surface. Over recent years, experimental and modelling techniques have been developed to study this anomalous regime of STM; however, there is a lack of a systematic classification of this scattered information. This review article thus serves the purpose of organizing all these results so as to enable a more comprehensive understanding of this phenomenon. We review the discovery of graphite superlattices, the observation of the associated properties, and the research efforts on this subject. An effort is made to envision the future experimental and theoretical research possibilities to unveil the mystery of this anomaly of STM. Applications of graphite superlattices are also proposed.

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Section: Large-scale Features Observed On Graphite Under Stmsupporting

confidence: 52%

Section: Number Of Attenuation Of Datamentioning

confidence: 99%

See 1 more Smart Citation

A review and outlook for an anomaly of scanning tunnelling microscopy (STM): superlattices on graphite

Pong

Durkan²

2005

J. Phys. D: Appl. Phys.

Self Cite

159

127

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“…c), the particle diameter increased slightly to 7.4 nm, but the height doubled to 0.4 nm. The question then arises on the nature of the observed nanoparticles organized in a regular hexagonal pattern on HOPG, Pt, or C. It was found in the literature that there is an anomaly of the STM related to superlattices on graphite, which are formed because of intrinsic defects of the substrate generated during crystal growth or cleavage. In principle, these particles could be associated to a graphite structure generated from the preparation of the surface before each experiment.…”

Section: Resultsmentioning

confidence: 99%

Spontaneous deposition of Pt‐nanoparticles on HOPG surfaces

Arroyo-Gómez

García

2015

Surface & Interface Analysis

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Pt nanoparticles were spontaneously generated by immersion of a highly ordered pyrolytic graphite substrate in a 1 mM H 2 PtCl 6 + 0.05 M H 2 SO 4 plating solution using different immersion times, modifying both size and density of the deposits. Atomic force microscopy images show Pt particles distributed preferentially on surface defects of the electrode, increasing their size and density with deposition time. Scanning electronic microscopy/energy-dispersive X-ray spectroscopy images confirmed the formation of Pt deposits after 2 h immersion, forming irregular agglomerates with different sizes distributed over the surface. The open circuit potential studies showed potentials close to the corresponding PtCl 6 2À /Pt and PtCl 4 2À /Pt couples, which would indicate that some of these processes took place at the interface. The voltammetric response of the supported Pt nanoparticles showed an increase in current density towards the hydrogen evolution reaction being more pronounced for deposits formed after an immersion time of 2 h. In this case, the voltammetric behavior was similar to polycrystalline Pt.

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“…Various publications have reported an attenuation factor (AF) associated with overlayer coverage of a moiré pattern in HOPG. 8,9,24 A fit of this data yields AF n = e 0.81n , where n is the number of overlayers. 10 In view of this, a second/third layer moiré pattern would be visible (AF 1 = 2.25) if present but the visibility of patterns from deeper layers decays exponentially.…”

Section: Multilayer Moirémentioning

confidence: 99%

Structural analysis of multilayer graphene via atomic moiré interferometry

et al. 2010

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Rotational misalignment of two stacked honeycomb lattices produces a moiré pattern that is observable in scanning tunneling microscopy as a small modulation of the apparent surface height. This is known from experiments on highly-oriented pyrolytic graphite. Here, we observe the combined effect of three-layer moiré patterns in multilayer graphene grown on SiC (0001). Small-angle rotations between the first and third layer are shown to produce a "double-moiré" pattern, resulting from the interference of moiré patterns from the first three layers. These patterns are strongly affected by relative lattice strain between the layers. We model the moiré patterns as a beat-period of the mismatched reciprocal lattice vectors and show how these patterns can be used to determine the relative strain between lattices, in analogy to strain measurement by optical moiré interferometry.

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Observation of Large-Scale Features on Graphite by Scanning Tunnelling Microscopy

Cited by 10 publications

References 12 publications

A review and outlook for an anomaly of scanning tunnelling microscopy (STM): superlattices on graphite

A review and outlook for an anomaly of scanning tunnelling microscopy (STM): superlattices on graphite

Spontaneous deposition of Pt‐nanoparticles on HOPG surfaces

Structural analysis of multilayer graphene via atomic moiré interferometry

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