Molecular-Scale Structure of Pentacene Interfaces with Si (111)

2006 ◽  
Vol 965 ◽  
Author(s):  
Soonjoo Seo ◽  
Paul G. Evans
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Structural Defects ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Semiconductor Thin Films ◽  
Disordered Layer ◽  
Temperature Scanning ◽  
Molecular Layers ◽  
Preparation Techniques ◽  
Imaging Conditions

ABSTRACTThe morphology and crystal structure of the first few molecular layers of organic semiconductor thin films at organic-inorganic interfaces are important from both electronic and structural perspectives. The first upright layer of pentacene on Si (111) forms on top of a disordered layer of strongly bonded pentacene molecules in a structure similar to the pentacene monolayers formed on insulators. We describe a high-resolution structural study of this crystalline phase of pentacene using low-temperature scanning tunneling microscopy (STM). The arrangement of molecules in these layers observed with STM agrees the results of with structural studies using scattering techniques. The imaging conditions and sample preparation techniques necessary to achieve molecular resolution can be adapted to subsequent STM and scanning tunneling spectroscopy experiments probing individual structural defects including vacancies, dislocations and grain boundaries within and between islands.

scholarly journals Orientation Ordering and Chiral Superstructures in Fullerene Monolayer on Cd (0001)

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1305
Author(s):  
Yuzhi Shang ◽  
Zilong Wang ◽  
Daxiao Yang ◽  
Yaru Wang ◽  
Chaoke Ma ◽  
...  
Keyword(s):  
Thin Films ◽  
Charge Transfer ◽  
Scanning Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Orientational Disorder ◽  
Temperature Scanning ◽  
Orientation Ordering ◽  
The Individual ◽  
Misorientation Angles

The structure of C60 thin films grown on Cd (0001) surface has been investigated from submonolayer to second monolayer regimes with a low-temperature scanning tunneling microscopy (STM). There are different C60 domains with various misorientation angles relative to the lattice directions of Cd (0001). In the (2√3 × 2√3) R30° domain, orientational disorder of the individual C60 molecules with either pentagon, hexagon, or 6:6 bond facing up has been observed. However, orientation ordering appeared in the R26° domain such that all the C60 molecules adopt the same orientation with the 6:6 bond facing up. In particular, complex chiral motifs composed of seven C60 molecules with clockwise or anticlockwise handedness have been observed in the R4° and R8° domains, respectively. Scanning tunneling spectroscopy (STS) measurements reveal a reduced HOMO–LOMO gap of 2.1 eV for the C60 molecules adsorbed on Cd (0001) due to the substrate screening and charge transfer from Cd to C60 molecules.

scholarly journals Defect-Induced π-Magnetism into Non-Benzenoid Nanographenes

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 224
Author(s):  
Kalyan Biswas ◽  
Lin Yang ◽  
Ji Ma ◽  
Ana Sánchez-Grande ◽  
Qifan Chen ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Open Shell ◽  
Scanning Tunneling Spectroscopy ◽  
Membered Ring ◽  
Structural Defects ◽  
Scanning Tunneling ◽  
Honeycomb Lattice ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force

The synthesis of nanographenes (NGs) with open-shell ground states have recently attained increasing attention in view of their interesting physicochemical properties and great prospects in manifold applications as suitable materials within the rising field of carbon-based magnetism. A potential route to induce magnetism in NGs is the introduction of structural defects, for instance non-benzenoid rings, in their honeycomb lattice. Here, we report the on-surface synthesis of three open-shell non-benzenoid NGs (A1, A2 and A3) on the Au(111) surface. A1 and A2 contain two five- and one seven-membered rings within their benzenoid backbone, while A3 incorporates one five-membered ring. Their structures and electronic properties have been investigated by means of scanning tunneling microscopy, noncontact atomic force microscopy and scanning tunneling spectroscopy complemented with theoretical calculations. Our results provide access to open-shell NGs with a combination of non-benzenoid topologies previously precluded by conventional synthetic procedures.

Study of YBCO/Au Surface Using Low-Temperature Scanning Tunneling Microscopy/Scanning Tunneling Spectroscopy

1992 ◽  
Vol 31 (Part 1, No. 11) ◽  
pp. 3525-3528 ◽  
Author(s):  
Masao Koyanagi ◽  
Satoshi Kashiwaya ◽  
Hiroshi Akoh ◽  
Satoshi Kohjiro ◽  
Mizushi Matsuda ◽  
...  
Keyword(s):  
Low Temperature ◽  
Scanning Tunneling Microscopy ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Temperature Scanning

scholarly journals On-Surface Synthesis of Variable Bandgap Nanoporous Graphene

2021 ◽  
Author(s):  
Dingguan Wang ◽  
Arramel Arramel ◽  
Xuefeng Lu ◽  
Yang Ming ◽  
Jishan Wu ◽  
...  
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Transport Layer ◽  
Single Atom ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Nanoporous Graphene ◽  
Charge Transport Layer ◽  
Temperature Scanning ◽  
Hybrid Devices

<p>Tuning the bandgap of nanoporous graphene is desirable for applications such as the charge transport layer in organic-hybrid devices. The holy grail in the field is the ability to synthesize 2D nanoporous graphene with variable pore sizes, and hence tuneable band gaps. Herein, we demonstrate the on-surface synthesis of nanoporous graphene with variable bandgaps. Two types of nanoporous graphene were synthesized via hierarchical C-C coupling, and verified by low-temperature scanning tunneling microscopy and non-contact atomic force microscopy with CO-terminated tip. Nanoporous graphene-1 is non-planar, and nanoporous graphene-2 is a single-atom thick planar sheet. Scanning tunneling spectroscopy measurements reveal that nanoporous graphene-2 has a bandgap of 3.8 eV, while nanoporous graphene-1 has a larger bandgap of 5.0 eV. Corroborated by first-principles calculations, we propose that the large bandgap opening is governed by the confinement of π-electrons induced by pore generation or the non-planar structure, and can be explained by Clar sextet theory. Our finding shows that by introducing nanopores, semimetallic graphene is converted into semiconducting nanoporous graphene-2 or insulating wide-bandgap nanoporous graphene-1. </p><br>

scholarly journals On-Surface Synthesis of Variable Bandgap Nanoporous Graphene

2021 ◽  
Author(s):  
Dingguan Wang ◽  
Arramel Arramel ◽  
Xuefeng Lu ◽  
Yang Ming ◽  
Jishan Wu ◽  
...  
Keyword(s):  
Scanning Tunneling Spectroscopy ◽  
Transport Layer ◽  
Single Atom ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Nanoporous Graphene ◽  
Charge Transport Layer ◽  
Temperature Scanning ◽  
Hybrid Devices

<p>Tuning the bandgap of nanoporous graphene is desirable for applications such as the charge transport layer in organic-hybrid devices. The holy grail in the field is the ability to synthesize 2D nanoporous graphene with variable pore sizes, and hence tuneable band gaps. Herein, we demonstrate the on-surface synthesis of nanoporous graphene with variable bandgaps. Two types of nanoporous graphene were synthesized via hierarchical C-C coupling, and verified by low-temperature scanning tunneling microscopy and non-contact atomic force microscopy with CO-terminated tip. Nanoporous graphene-1 is non-planar, and nanoporous graphene-2 is a single-atom thick planar sheet. Scanning tunneling spectroscopy measurements reveal that nanoporous graphene-2 has a bandgap of 3.8 eV, while nanoporous graphene-1 has a larger bandgap of 5.0 eV. Corroborated by first-principles calculations, we propose that the large bandgap opening is governed by the confinement of π-electrons induced by pore generation or the non-planar structure, and can be explained by Clar sextet theory. Our finding shows that by introducing nanopores, semimetallic graphene is converted into semiconducting nanoporous graphene-2 or insulating wide-bandgap nanoporous graphene-1. </p><br>

NONEQUILIBRIUM EFFECTS AND MANY-PARTICLE INTERACTION IN TUNNELING SPECTROSCOPY OF IMPURITY d-ORBITAL

2003 ◽  
Vol 02 (06) ◽  
pp. 575-584 ◽  
Author(s):  
P. I. ARSEYEV ◽  
N. S. MASLOVA ◽  
V. I. PANOV ◽  
S. V. SAVINOV ◽  
CHRIS VAN HAESENDONCK
Keyword(s):  
Particle Interaction ◽  
Scanning Tunneling Spectroscopy ◽  
Opposite Polarity ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Nonequilibrium Processes ◽  
Temperature Scanning ◽  
P Type ◽  
Stm Images

We report the direct observation by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy of the d-orbital of a Mn p-type impurity appearing on a cleaved InAs (110) surface. STM images reveal remarkable cross-like protrusions and round depressions around isolated impurity atom on the surface at opposite polarity of tunneling bias voltage. By means of diagram technique for nonequilibrium processes we show that the crucial interplay between nonequilibrium charging effects and many-particle interaction leading to Coulomb singularities provides a consistent description of the experimental results.

Scanning tunneling microscopy of E. coli RNA polymerase deposited onto an Au substrate by an electrochemical process

1991 ◽  
Vol 49 ◽  
pp. 378-379
Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear
Keyword(s):  
Scanning Tunneling Microscope ◽  
Biological Sample ◽  
Substrate Surface ◽  
Electrochemical Process ◽  
Atomic Resolution ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Tunneling Microscope ◽  
E Coli ◽  
Preparation Techniques

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.

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