STS INVESTIGATIONS OF METALLIC NANOSTRUCTURES DEPOSITED ON Bi2Te3

2007 ◽  
Vol 14 (03) ◽  
pp. 357-360
Author(s):  
SZYMON WINIARZ ◽  
PIOTR BISKUPSKI ◽  
STANISLAW SZUBA ◽  
SLAWOMIR MIELCAREK ◽  
RYSZARD CZAJKA
Keyword(s):  
High Vacuum ◽  
Metallic Nanostructures ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Scanning Tunneling ◽  
Superlattice Structure ◽  
Potential Applications ◽  
Subsequent Calculation

Bi 2 Te 3 has attracted attention due to its potential applications in the microfabrication of integrated thermoelectric devices. It is also interesting to study the metallization process of this compound. Metallic nanostructures were deposited by means of an electron gun evaporator in ultra high vacuum (UHV) conditions (10-8 Pa) on the freshly cleaved 0001 surface of the crystal Bi 2 Te 3. Measurements were conducted using the commercially available Omicron UHV scanning tunneling microscope (STM). Scanning tunneling spectroscopy (STS) measurements were performed using current imaging tunneling spectroscopy (CITS), and subsequent calculation of the dI/dV maps. Metallic characteristics were observed on nickel islands since early stages of the growth. CITS and dI/dV maps showed distinct contrast between the substrate and metallic islands. Similar contrast was not observed in the case of titanium, most probably due to an intercalation process. Occurring of such a process was confirmed by the appearance of the superlattice structure.

Design of Ultra High Vacuum Scanning Electron Microscope Combined with Scanning Tunneling Microscope

1992 ◽  
Vol 295 ◽  
Author(s):  
Mikio Takai ◽  
Naoki Yokoi ◽  
Ryou Mimura ◽  
Hiroshi Sawaragi ◽  
Ryuso Aihara
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Scanning Tunneling Microscope ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Gun ◽  
Scanning Tunneling ◽  
Tunneling Microscope ◽  
Wide Range ◽  
Scanning Electron

AbstractAn ultra high vacuum (UHV) scanning electron microscope (SEM) combined with a scanning tunneling microscope (STM) has been designed and constructed to solve problems, arising from STM surface imaging and nanofabrication using STM tips, such as difficulty in probe tip location and change in tip shape. The system facilitates to image and/or to modify a wide range of area from submicron down to subnanometer. A ZrO/W thermal emitter in a Schottky mode has been used for an electron gun to obtain a low energy spread with a high angular current density. Minimum beam spot diameters of 6 and 12 nm with currents of 100 pA and 4 nA are estimated by optical property calculation for high resolution (SEM) and high current (fabrication) modes, respectively.

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.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Scanning-tunneling spectroscopy on conjugated polymer films

2003 ◽  
Vol 771 ◽  
Author(s):  
M. Kemerink ◽  
S.F. Alvarado ◽  
P.M. Koenraad ◽  
R.A.J. Janssen ◽  
H.W.M. Salemink ◽  
...  
Keyword(s):  
Polymer Films ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Direct Consequence ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Band Alignment ◽  
Scanning Tunneling ◽  
Order Of Magnitude

AbstractScanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current, which can amount to more than an order of magnitude, and can even change the polarity of the dominant charge carrier. As a direct consequence, the single-particle band gap and band alignment of the organic material can be directly obtained from tip height-voltage (z-V) curves, provided that the tip has a sufficiently sharp apex.

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.

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