Geometric and Electronic Structure of Fullerene Film Growth as a Function of Coverage

1994 ◽  
Vol 359 ◽  
Author(s):  
B. Reihl
Keyword(s):  
Electronic Structure ◽  
Low Temperatures ◽  
Film Growth ◽  
Theoretical Calculations ◽  
Scanning Tunneling ◽  
Island Growth ◽  
Tunneling Microscopy ◽  
Adsorption Sites ◽  
Adsorbed Monolayer ◽  
Inverse Photoemission

ABSTRACTWe have employed scanning tunneling microscopy at room and low temperature, i.e. 300, 50, and 5 K, to study the epitaxy and growth of fullerene films on the noble-metal surfaces Ag(110) and Au(110). Initial island growth occurs on terrace sites away from substrate step edges. Particularly at low temperatures where the rotational and vibrational movements of the fullerene molecules are frozen in, different intra-molecular topographic patterns become visible in ordered films, which are characteristic of particular adsorption sites. Complementary tunneling spectroscopy and direct and inverse photoemission measurements reveal distinct differences between the first adsorbed monolayer and additional fullerene layers indicating differences in bonding and charge transfer. Our results are compared to theoretical calculations.

Modeling of Metal(100) Homoepitaxial Film Growth at Very Low Temperatures

2000 ◽  
Vol 619 ◽  
Author(s):  
K.J. Caspersen ◽  
C.R. Stoldt ◽  
P.A. Thiel ◽  
J.W. Evans
Keyword(s):  
Low Temperatures ◽  
Film Growth ◽  
Diffusion Processes ◽  
Variable Temperature ◽  
Scanning Tunneling ◽  
Film Morphology ◽  
Tunneling Microscopy ◽  
Adsorption Sites ◽  
Temperature Scanning ◽  
Homoepitaxial Film

ABSTRACTWe model the growth of Ag films deposited on Ag(100) below 140K. Our recent Variable-Temperature Scanning Tunneling Microscopy (VTSTM) studies reveal “smooth growth” from 120-140K, consistent with earlier diffraction studies. However, we also find rougher growth for lower temperatures. This unexpected behavior is modeled by describing the deposition dynamics using a “restricted downward funneling” model, wherein deposited atoms get caught on the sides of steep nanoprotrusions (which are prevalent below 120K), rather than always funneling down to lower four-fold hollow adsorption sites. At OK, where no thermal diffusion processes are operative, this leads to the formation of overhangs and internal defects (or voids). Above 40K, low barrier interlayer diffusion processes become operative, producing the observed smooth growth by 120K. We also discuss how the apparent film morphology mapped out by the STM tip “smears” features of the actual film morphology (which are small at low temperature), and also can lead to underestimation of the roughness.

scholarly journals Kinetic Roughening of Multilayer Ag/Ag(100) Films: Complex Temperature-Dependence in a Simple System

2000 ◽  
Vol 619 ◽  
Author(s):  
C.R. Stoldt ◽  
K.J. Caspersen ◽  
M.C. Bartelt ◽  
C.J. Jenks ◽  
J.W. Evans ◽  
...  
Keyword(s):  
Lattice Gas ◽  
Film Growth ◽  
Kinetic Monte Carlo ◽  
Variable Temperature ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Adsorption Sites ◽  
Lattice Gas Models ◽  
Temperature Scanning ◽  
Complex Temperature

ABSTRACTMetal(100) homoepitaxial systems constitute perhaps the simplest class of systems in which to study thin film growth. Yet, our Variable-Temperature Scanning Tunneling Microscopy (VTSTM) analysis of Ag/Ag(100) homoepitaxy reveals that the variation of roughness with temperature is extraordinarily complex. As the deposition temperature is reduced from 300K to 50K, the roughness of 25 monolayer films first increases, then decreases, and then increases again. Furthermore, a transition from mound formation to self-affine (semi-fractal) growth occurs at around 135K. We postulate that the following the atomistic mechanisms underly this behavior: the existence of a small step-edge barrier inhibiting diffusive downward transport; “downward funneling” of atoms deposited at step edges and microprotrusions towards lower four-fold hollow adsorption sites; and statistically significant deviations from “complete” downward funneling at lower temperatures, where deposited atoms instead become trapped on the sides of (the more prevalent) small steep microprotrusions. To support these postulates, we employ kinetic Monte Carlo simulations to show that atomistic (lattice-gas) models for epitaxial growth, which incorporate these mechanisms, reproduce the experimental data quantitatively.

scholarly journals The Growth of Strained Thin Films of Gadolinium

1998 ◽  
Vol 528 ◽  
Author(s):  
C. Waldfried ◽  
O. Zeybek ◽  
T. Bertrams ◽  
S. D. Barrett ◽  
P.A. Dowben
Keyword(s):  
Thin Films ◽  
Electronic Structure ◽  
Film Growth ◽  
Growth Direction ◽  
Low Energy ◽  
Domain Growth ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

AbstractThe growth of strained thin films of gadolinium has been investigated with low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) and compared to the film growth of unstrained gadolinium. Strained thin films of gadolinium are distinct from the unstrained films by a substrate induced preferential domain growth direction, which is also reflected in the electronic structure.

SCANNING TUNNELING MICROSCOPY OF CLUSTERS ADSORBED ON SUPERPERIODIC LATTICE OF HIGHLY ORIENTED PYROLYTIC GRAPHITE

1996 ◽  
Vol 03 (01) ◽  
pp. 983-986
Author(s):  
N. HORIGUCHI ◽  
A. KASUYA ◽  
Y. NISHINA
Keyword(s):  
Electronic Structure ◽  
Scanning Tunneling Microscopy ◽  
Bias Voltage ◽  
Pyrolytic Graphite ◽  
Scanning Tunneling ◽  
Highly Oriented Pyrolytic Graphite ◽  
Tunneling Microscopy ◽  
Adsorption Sites ◽  
Surface Electronic Structure

We observed superperiodic lattices in clusters deposited on HOPG surfaces by STM. Furthermore, we clearly identified two types of bias-voltage dependences in the corrugation of superperiodic lattices. Cluster adsorption sites are strongly influenced by the superperiodic lattices. On the superperiodic lattices, clusters are found to form arrays. This suggests that one can control the surface electronic structure as well as the cluster array by preparing graphitic sheets with various stacking arrangements.

Room temperature observation of the correlation between atomic and electronic structure of graphene on Cu(110)

RSC Advances ◽  
2016 ◽  
Vol 6 (100) ◽  
pp. 98001-98009 ◽  
Author(s):  
Thais Chagas ◽  
Thiago H. R. Cunha ◽  
Matheus J. S. Matos ◽  
Diogo D. dos Reis ◽  
Karolline A. S. Araujo ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Chemical Vapor Deposition ◽  
Scanning Tunneling Microscopy ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Temperature Observation ◽  
Atomic And Electronic Structure

We have used atomically-resolved scanning tunneling microscopy and spectroscopy to study the interplay between the atomic and electronic structure of graphene formed on copper via chemical vapor deposition.

scholarly journals Study on Formation Process and Models of Linear Fe Cluster Structure on a Si(111)-7 × 7-CH3OH Surface

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1593
Author(s):  
Wenxin Li ◽  
Wanyu Ding ◽  
Dongying Ju ◽  
Ken-ichi Tanaka ◽  
Fumio Komori
Keyword(s):  
Formation Process ◽  
Surface Display ◽  
Cluster Structure ◽  
Scanning Tunneling ◽  
Magnetic Memory ◽  
Face Centered Cubic ◽  
Tunneling Microscopy ◽  
Height Measurement ◽  
Adsorption Sites ◽  
Spectrometer Data

STM results showed that Fe atoms were deposited on a Si(111)-7 × 7 reconstructed surface, which was saturated with CH3OH molecules. Fe atomic linear structure was composed of stable clusters and in-situ observed by the scanning tunneling microscopy (STM). The aim to improve its application of magnetic memory material, both formation process and models, has been explored in this paper. By combining surface images and mass spectrometer data, an intermediate layer model was established. In terms of thermal stability, the most favorable adsorption sites of CH3OH were further explored. After that, Fe atoms were deposited on the Si(111)-7 × 7-CH3OH surface, forming a linear cluster structure. On the one hand, a new Fe cluster model was put forward in this paper, which was established with height measurement and 3D surface display technology. This model is also affected by the evaporation temperature, which can be consistent with the atomic stacking pattern of face centered cubic structures. On the other hand, the slight height change suggested the stability of linear structures. Even in the condition of thin air introduction, Fe cluster showed a good performance, which suggested the possibility of magnetic memory application in the future. These investigations are believed to have, to a certain extent, increased the probability of forming Fe linear clusters on the surface of silicon substrate, especially according to the models and surface technology we adjusted.

scholarly journals STM study on the self-assembly of oligothiophene-based organic semiconductors

2011 ◽  
Vol 2 ◽  
pp. 802-808 ◽  
Author(s):  
Elena Mena-Osteritz ◽  
Marta Urdanpilleta ◽  
Erwaa El-Hosseiny ◽  
Berndt Koslowski ◽  
Paul Ziemann ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Self Assembly ◽  
Theoretical Calculations ◽  
The Self ◽  
Scanning Tunneling ◽  
Ambient Conditions ◽  
Tunneling Microscopy ◽  
Substitution Pattern ◽  
Electronic Density ◽  
The Individual

The self-assembly properties of a series of functionalized regioregular oligo(3-alkylthiophenes) were investigated by using scanning tunneling microscopy (STM) at the liquid–solid interface under ambient conditions. The characteristics of the 2-D crystals formed on the (0001) plane of highly ordered pyrolitic graphite (HOPG) strongly depend on the length of the π-conjugated oligomer backbone, on the functional groups attached to it, and on the alkyl substitution pattern on the individual thiophene units. Theoretical calculations were performed to analyze the geometry and electronic density of the molecular orbitals as well as to analyze the intermolecular interactions, in order to obtain models of the 2-D molecular ordering on the substrate.

Density fluctuations as door-opener for diffusion on crowded surfaces

Science ◽  
2019 ◽  
Vol 363 (6428) ◽  
pp. 715-718 ◽  
Author(s):  
Ann-Kathrin Henß ◽  
Sung Sakong ◽  
Philipp K. Messer ◽  
Joachim Wiechers ◽  
Rolf Schuster ◽  
...  
Keyword(s):  
High Speed ◽  
Density Functional ◽  
Local Density ◽  
Variable Temperature ◽  
Industrial Process ◽  
Density Fluctuations ◽  
Scanning Tunneling ◽  
Fast Diffusion ◽  
Tunneling Microscopy ◽  
Adsorption Sites

How particles can move on a catalyst surface that, under the conditions of an industrial process, is highly covered by adsorbates and where most adsorption sites are occupied has remained an open question. We have studied the diffusion of O atoms on a fully CO-covered Ru(0001) surface by means of high-speed/variable-temperature scanning tunneling microscopy combined with density functional theory calculations. Atomically resolved trajectories show a surprisingly fast diffusion of the O atoms, almost as fast as on the clean surface. This finding can be explained by a “door-opening” mechanism in which local density fluctuations in the CO layer intermittently create diffusion pathways on which the O atoms can move with low activation energy.

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