Origin of flat morphology and high crystallinity of ultrathin bismuth films

Yaginuma, Shin; Nagao, Tadaaki; Sadowski, Jerzy; Saito, Mineo; Nagaoka, Keizo; Fujikawa, Y.; Sakurai, Takeshi; Nakayama, Tomonobu

doi:10.1016/j.susc.2007.06.075

Cited by 85 publications

(79 citation statements)

References 22 publications

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“…A similar diffuse ring has previously been reported for Bi films on the fivefold surface of the icosahedral Al-Pd-Mn quasicrystalline or on the Si(111)-7 × 7 surface. 10,11,23 The intensity of this diffuse ring depends on the fraction of the surface covered with Bi(110) islands and their size. The fraction of Bi(110) islands is certainly smaller on the Al 13 Co 4 substrate compared to these systems, because they compete with the Bi(111) orientation already in the early stage of thin film growth.…”

Section: Multilayer Regime At 300 Kmentioning

confidence: 99%

Competing allotropes of Bi deposited on the Al13Co4(100) alloy surface

et al. 2012

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The growth and stability of Bi thin films on the Al 13 Co 4 (100) surface has been investigated from the submonolayer to high-coverage regime by scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) for temperatures ranging from 57 to 633 K. Initially, Bi adsorption leads to the formation of a pseudomorphic monolayer, followed by the growth of islands of different heights with increasing coverage. The in-plane structure, island height, and island morphology indicate that these islands adopt either a pseudocubic (110) or hexagonal (111) orientation normal to the surface. The (110)-oriented islands correspond to bilayer stacking (either two or four monolayers in height) while the (111)-oriented islands correspond to either three-or four-layer stacking. The in-plane orientation of (110) islands with respect to the substrate is random, while (111) islands adopt one of four possible orientations. In addition, the (111) islands show a moiré structure. The fact that Bi islands grow with either (110) or (111) orientation simultaneously on the same substrate relates to a subtle energy balance between both orientations according to ab initio calculations, allowing both structures to coexist. The island density dependence versus both deposition temperature and flux, their most frequent structure type, reshaping effects, and chemical reactivity of the different allotropes are also discussed in this paper.

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Section: Multilayer Regime At 300 Kmentioning

confidence: 99%

Competing allotropes of Bi deposited on the Al13Co4(100) alloy surface

et al. 2012

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“…Moiré patterns were previously observed for nanostructured bismuth films deposited on GaAs [15], Au [33], Si(111) [34], and quasicrystals [35]; however, no detailed investigation of the origin of these patterns was performed until now. We show here that moiré patterns are observed for 3 monolayer (ML) thick Bi islands on highly oriented pyrolytic graphite (HOPG) and investigate the morphological and electronic structure of these islands using STM and scanning tunneling spectroscopy (STS).…”

Section: Introductionmentioning

confidence: 98%

Origin of the moiré pattern in thin Bi films deposited on HOPG

et al. 2015

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Thin Bi(110) films deposited on highly oriented pyrolytic graphite (HOPG) exhibit a pronounced moiré pattern; here the origin of the moiré pattern is investigated using scanning tunneling microscopy (STM) and spectroscopy (STS), high-resolution transmission electron microscopy (HR-TEM), and density functional theory (DFT). It is shown that the moiré pattern forms only on islands which are misoriented by ∼30• with respect to the usual substrate symmetry direction. Two models of the moiré pattern are presented: (i) a commensurate monolayer construction (CMC) for rectangular overlayer symmetry on hexagonal substrates and (ii) a qualitative model based on simple superposition of a Bi overlayer on graphene. The CMC model has previously been applied only to systems with pure hexagonal symmetry. Both models generate moiré patterns with key parameters (period, angles of the pattern measured with respect to the main HOPG and Bi crystal directions) that are consistent with the experimental results, but development of a fully predictive/quantitative model remains an outstanding challenge. The electronic structure of the moiré pattern is investigated using STS and DFT, and it is found that the local density of states (LDOS) is modulated by the moiré pattern. These results are consistent with a picture in which a small distortion of Bi atomic positions at the film-substrate interface results in periodic modulation of the LDOS, hence allowing observation of the moiré pattern in STM images.

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“…This choice of substrate is also very beneficial for practical applications, as the interface between film and insulating substrate, expected to reveal topological states, will also be protected from influencing oxidation effects arising from ambient exposure in technological applications [19]. The growth of Bi has been extensively studied on Si(111) [20][21][22][23][24][25][26][27][28][29] and HOPG [13,[30][31][32] as well as other surfaces [3,4,12,[33][34][35][36][37][38], resulting in fabrication of films with a range of different morphologies, orientations, and strain. The fabrication of Bi films has attracted considerable interest in recent years, as their controlled growth, with focus on morphology and crystallographic orientation, on semiconductor and oxide surfaces is not a trivial task.…”

Section: Introductionmentioning

confidence: 99%