The Formation and Evolution of InAs 3D Islands on GaAs(001) and a Comparative C-AFM and NC-AFM Study of InAs 3D Islands

1996 ◽  
Vol 440 ◽  
Author(s):  
T. R. Ramachandran ◽  
N. P. Kobayashi ◽  
R. Heitz ◽  
P. Chen ◽  
A. Madhukar
Keyword(s):  
High Vacuum ◽  
Three Dimensional ◽  
Ultra High Vacuum ◽  
Condition Dependence ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Contact Mode ◽  
Force Microscopy ◽  
Highly Strained ◽  
2D To 3D

AbstractThe two-dimensional (2D) to three-dimensional (3D) morphology change in the highly strained growth of InAs on GaAs(001) is examined via in-situ, ultra-high vacuum (UHV) scanning tunneling microscopy (STM) and contact-mode atomic force microscopy (C-AFM). The formation of 3D InAs islands (˜2–4nm high) at an InAs delivery, θ˜1.57ML is found to be preceded by the appearance of small quasi-3D clusters (˜0.6–1.2nm high). The 2D to 3D transition is found to occur over a range of θ from ˜1.45ML to 1.74ML, with a varying and gradual mass transfer from 2D to 3D features with increasing θ. The InAs 3D islands are also examined in this study using non-contact AFM (NC-AFM) in order to assess the usefulness of this technique for imaging 3D features. Unlike the constancy observed in the C-AFM images, the NC-AFM images exhibit a marked imaging condition dependence. The variability observed in the NC-AFM images is qualitatively compared to the outcome of the simplest, force-gradient model of NC-AFM in order to extract a guideline for NC-AFM imaging of 3D features.

Industrial Applications of Scanning Probe Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 522-523
Author(s):  
S. Magonov
Keyword(s):  
Scanning Probe Microscopy ◽  
High Vacuum ◽  
Sample Surface ◽  
Industrial Applications ◽  
Ultra High Vacuum ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Probe Microscopy ◽  
Force Microscopy

The evolution of scanning tunneling microscopy (STM) into atomic force microscopy (AFM) have led to a family of scanning probe techniques which are widely applied in fundamental research and in industry. Visualization of the atomic- and molecular-scale structures and the possibility of modifying these structures using a sharp probe were demonstrated with the techniques on many materials. These unique capabilities initiated the further development of AFM and related methods generalized as scanning probe microscopy (SPM). The first STM experiments were performed in the clean conditions of ultra-high vacuum and on well-defined conducting or semi-conducting surfaces. These conditions restrict SPM applications to the real world that requires ambient-condition operation on the samples, many of which are insulators. AFM, which is based on the detection of forces between a tiny cantilever carrying a sharp tip and a sample surface, was introduced to satisfy these requirements. High lateral resolution and unique vertical resolution (angstrom scale) are essential AFM features.

Comparative Studies of Pb/Cu(001) by TEM, AFM and STM

1998 ◽  
Vol 528 ◽  
Author(s):  
Franck Bocquet ◽  
Camille Cohen ◽  
Didier Schmaus ◽  
André Rocher ◽  
Jacques Crestou ◽  
...  
Keyword(s):  
Accurate Determination ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Specific Orientation

AbstractThe same specimen of Pb/Cu grown under Ultra High Vacuum (UHV) conditions has been investigated by Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). We show that the information obtained by these techniques is consistent when comparable, and complementary. In particular, three different morphologies of Pb islands with specific orientation relationship are observed; AFM reveals the faceted shape of the islands; STM permits an accurate determination of the atomic structure of the facets; TEM moir6 patterns reveal that Pb islands are well relaxed.

Construction Of UHV-REM-PEEM for Surface Studies

1990 ◽  
Vol 48 (1) ◽  
pp. 350-351
Author(s):  
Y. Kondo ◽  
K. Yagi ◽  
K. Kobayashi ◽  
H. Kobayashi ◽  
Y. Yanaka
Keyword(s):  
Electron Microscopy ◽  
Electronic Structure ◽  
High Vacuum ◽  
Scanning Tunneling Spectroscopy ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Surface Electronic Structure ◽  
Electron Microscopes

Recent development of ultra-high vacuum electron microscopy (UHV-EM) is very rapid. This is due to the fact that it can be applied to variety of surface science fields.There are various types of surface imaging in UHV condition; low energy electron microscopy (LEEM) [1], transmission (TEM) and reflection electron microscopy (REM) [2] using conventional transmission electron microscopes (CTEM) (including scanning TEM and REM)), scanning electron microscopy, photoemission electron microscopy (PEEM) [3] and scanning tunneling microscopy (STM including related techniques such as scanning tunneling spectroscopy (STS), atom force microscopy and magnetic force microscopy)[4]. These methods can be classified roughly into two; in one group image contrast is mainly determined by surface atomic structure and in the other it is determined by surface electronic structure. Information obtained by two groups of surface microscopy is complementary with each other. A combination of the two methods may give images of surface crystallography and surface electronic structure. STM-STS[4] and LEEM-PEEM [3] so far developed are typical examples.In the present work a combination of REM(TEM) and PEEM (Fig. 1) was planned with use of a UHV CTEM. Several new designs were made for the new microscope.

scholarly journals Formation of Micro- and Nano-Trenches on Epitaxial Graphene

2018 ◽  
Vol 8 (12) ◽  
pp. 2518 ◽  
Author(s):  
Tingwei Hu ◽  
Xiangtai Liu ◽  
Dayan Ma ◽  
Ran Wei ◽  
Kewei Xu ◽  
...  
Keyword(s):  
High Vacuum ◽  
Epitaxial Graphene ◽  
Ultra High Vacuum ◽  
Metal Particles ◽  
Damage Effect ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atmosphere Environment ◽  
Relationship Of

Catalytic cutting by metal particles under an atmosphere environment is a promising method for patterning graphene. Here, long straight micro-trenches are produced by the sliding of metal particles (Ag and In) on epitaxial graphene (EG) substrate under the ultra-high vacuum (UHV) annealing. The morphology and orientation relationship of the micro-trenches are observed by scanning electron microscopy (SEM), and the damage effect is confirmed by Raman scattering. Atomic force microscopy (AFM) and scanning tunneling microscopy (STM) are further adopted to atomically characterize the sliding behavior of metal particles, which resembles a similar etching method and can be used to make graphene nano-trenches. The study provides us with more understanding about the mutual effects between metals on EG, which hopes to pave the way for the applications of graphene-based devices.

scholarly journals Strain-Relief Patterns and Kagome Lattice in Self-Assembled C60 Thin Films Grown on Cd(0001)

2021 ◽  
Vol 22 (13) ◽  
pp. 6880
Author(s):  
Zilong Wang ◽  
Minlong Tao ◽  
Daxiao Yang ◽  
Zuo Li ◽  
Mingxia Shi ◽  
...  
Keyword(s):  
Thin Films ◽  
Self Assembly ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Kagome Lattice ◽  
Tunneling Microscopy ◽  
Kagomé Lattice ◽  
Temperature Scanning ◽  
C60 Films

We report an ultra-high vacuum low-temperature scanning tunneling microscopy (STM) study of the C60 monolayer grown on Cd(0001). Individual C60 molecules adsorbed on Cd(0001) may exhibit a bright or dim contrast in STM images. When deposited at low temperatures close to 100 K, C60 thin films present a curved structure to release strain due to dominant molecule–substrate interactions. Moreover, edge dislocation appears when two different wavy structures encounter each other, which has seldomly been observed in molecular self-assembly. When growth temperature rose, we found two forms of symmetric kagome lattice superstructures, 2 × 2 and 4 × 4, at room temperature (RT) and 310 K, respectively. The results provide new insight into the growth behavior of C60 films.

scholarly journals Au(100) as a Template for Pentacene Monolayer

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2393
Author(s):  
Artur Trembułowicz ◽  
Agata Sabik ◽  
Miłosz Grodzicki
Keyword(s):  
Self Assembly ◽  
Molecular Layer ◽  
High Vacuum ◽  
Gold Surface ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Height Difference ◽  
Characteristic Features ◽  
Reconstructed Surface

The surface of quasi-hexagonal reconstructed Au(100) is used as the template for monolayer pentacene (PEN) self-assembly. The system is characterized by means of scanning tunneling microscopy at room temperature and under an ultra-high vacuum. A new modulated pattern of molecules with long molecular axes (MA) arranged along hex stripes is found. The characteristic features of the hex reconstruction are preserved herein. The assembly with MA across the hex rows leads to an unmodulated structure, where the molecular layer does not recreate the buckled hex phase. The presence of the molecules partly lifts the reconstruction—i.e., the gold hex phase is transformed into a (1×1) phase. The arrangement of PEN on the gold (1×1) structure is the same as that of the surrounding molecular domain on the reconstructed surface. The apparent height difference between phases allows for the distinction of the state of the underlying gold surface.

Using a Moderate Vacuum, Hot/Cryo-Stage Equipped AFM for In-Situ Observation of α-Phase Growth In 60SN40PB Hypoeutectic Solder

1998 ◽  
Vol 4 (S2) ◽  
pp. 316-317
Author(s):  
D. N. Leonard ◽  
P.E. Russell
Keyword(s):  
Surface Science ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
In Situ Observation ◽  
Atmospheric Conditions ◽  
Tunneling Microscopy ◽  
Wide Range ◽  
Gas Environment

Atomic force microscopy (AFM) was introduced in 1984, and proved to be more versatile than scanning tunneling microscopy (STM) due to the AFM's capabilities to scan non-conductive samples under atmospheric conditions and achieve atomic resolution. Ultra high vacuum (UHV) AFM has been used in surface science applications when control of oxidation and corrosion of a sample's surface are required. Expensive equipment and time consuming sample exchanges are two drawbacks of the UHV AFM system that limit its use. Until recently, no hot/cryo-stage, moderate vacuum, controlled gas environment AFM was commonly available.We have demonstrated that phase transformations are easily observable in metal alloys and polymers with the use of a moderate vacuum AFM that has in-situ heating/cooling capabilities and quick (within minutes) sample exchange times. This talk will describe the results of experiments involving a wide range of samples designed to make use of the full capabilities of a hot/cryo-stage, controlled gas environment AFM.

Scanning Tunneling Microscopy Observation Of Single Dangling Bonds on the Si(100)2×1:H Surface

2001 ◽  
Vol 705 ◽  
Author(s):  
Lequn Liu ◽  
Jixin Yu ◽  
Joseph W. Lyding
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Negative Charge ◽  
High Vacuum ◽  
Surface Current ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Dangling Bonds ◽  
Tunneling Microscopy ◽  
Current Image ◽  
P Type

AbstractThe electrical properties of single dangling bonds on the Si(100)2×1:H surface are investigated by ultra high vacuum scanning tunneling microscopy. On the N-type Si(100)2×1:H surface, single dangling bonds created by feedback controlled lithography and natural dangling bonds have a fixed negative charge. On the other hand, they are observed as neutral on the P-type Si(100)2×1:H surface. Current image tunneling spectroscopy is used to characterize both types of dangling bonds. The dangling bonds with fixed negative charge display a dramatic voltage dependence with Friedel oscillations observed in the empty state images. The neutral dangling bonds appear as protrusions in both the empty and filled state images.

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