IMPROVED CHEMICAL SYNTHESIS OF GRAPHENE USING A SAFER SOLVOTHERMAL ROUTE

2011 ◽  
Vol 10 (01n02) ◽  
pp. 39-42 ◽  
Author(s):  
DILIP KUMAR SINGH ◽  
P. K. IYER ◽  
P. K. GIRI
Keyword(s):  
Electron Microscopy ◽  
Graphene Sheets ◽  
Pyrolysis Process ◽  
High Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Analysis ◽  
Bulk Production

Graphene has been synthesized using thermal decomposition of ethyl alcohol in a medium pressure autoclave. The synthesis was carried out in the presence of strong alkaline solution at a temperature of ~230°C and pressure of 60 bar. The as-synthesized graphene has been characterized using atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). AFM analysis on various graphene sheets shows the presence of monolayer (n = 1) to trilayer (n = 3) graphene sheets with thickness of ~1.168 nm. HRTEM studies confirm the high quality of graphene obtained after purification of as-synthesized product. Use of chemically nonexplosive material for synthesis and reduced reaction time along with the absence of post-pyrolysis process make it a commercially viable process for bulk production of graphene.

Epitaxial Growth of Nb Films and Nb/Cu Bilayers on A12O3 Substrates by DC Magnetron Sputtering

1998 ◽  
Vol 528 ◽  
Author(s):  
R. Loloee ◽  
M.A. Crimp ◽  
W. Zhu ◽  
W.P. Pratt
Keyword(s):  
Electron Microscopy ◽  
Sputter Deposition ◽  
Dc Magnetron Sputtering ◽  
High Quality ◽  
Cu Films ◽  
Force Microscopy ◽  
Sputtered Films ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Transmission Electron

AbstractEpitaxial single crystal Nb films have been grown by sputter deposition on (1 1 2 0) sapphire substrates. Subsequently, high quality epitaxial Cu films, with two orientation variants, have been grown onto the epitaxial Nb films. The sputtered films have been characterized using atomic force microscopy, electron backscattered patterns, and conventional transmission electron microscopy.

ORIGIN OF ORDERING OSCILLATION OF LOCAL COMPOSITION IN MELT-PROCESSED REBa2Cu3O7-δ SUPERCONDUCTORS (RE: Sm, Eu, Gd)

2005 ◽  
Vol 19 (01n03) ◽  
pp. 159-161
Author(s):  
A. HU ◽  
N. SAKAI ◽  
I. HIRABAYASHI ◽  
M. WINTER ◽  
M. R. KOBLISCHKA ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Superconducting Transition ◽  
High Quality ◽  
Local Composition ◽  
Pinning Centers ◽  
Force Microscopy ◽  
Atomic Force ◽  
Novel Structure ◽  
Transmission Electron ◽  
Field Dependent

High quality melt-processed ( Sm 0.33 Eu 0.33 Gd 0.33) Ba 2 Cu 3 O 7-δ superconductors were grown and microstructural origin of their distinguished superconducting performance was investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM) and the field dependent superconducting transition performed with SQUID. A nanoscopic periodic array of chemical composition was unveiled. This novel structure acted as δTc-style pinning centers.

Micropattern analysis of ZnIn2S4 using AFM and TEM

1995 ◽  
Vol 53 ◽  
pp. 476-477
Author(s):  
L. Martinez ◽  
J. M. Briceño-Valero ◽  
S. A. López-Rivera ◽  
K. Moore ◽  
J. T. Thorthon
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Layer Structure ◽  
Growth Direction ◽  
Intrinsic Nature ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Afm Analysis ◽  
Optical Applications

Semiconductor ZnIn2S4 is the only member of the II-III2-IV4 family with layer structure. The crystal structure of this semiconductor reported by Lappe et. al. is based upon closed packing of sulfur atoms with octahedral and tetrahedral indium atoms and tetrahedral zinc atoms. Previous studies on this material with high resolution transmission electron microscopy and Ramman spectroscopy demonstrate the existence of challenging problems to be resolved related to its intrinsic nature. There is great interest in this material for possible non-linear optical applications. In the present study Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) have been utilized to reveal crystallographic aspects of this material.Yellowish, plate-shaped, single crystals of ZnIn2S4 were prepared with the chemical transport method using iodine as a transporting agent. Specimens suitable for electron microscope analysis in the growth direction were prepared by peeling off layers with a piece of tape. For AFM analysis, freshly cleaved surfaces were used.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

scholarly journals Epitaxial Growth of Ordered In-Plane Si and Ge Nanowires on Si (001)

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 788
Author(s):  
Jian-Huan Wang ◽  
Ting Wang ◽  
Jian-Jun Zhang
Keyword(s):  
Electron Microscopy ◽  
Epitaxial Growth ◽  
Molecular Beam ◽  
Core Shell ◽  
High Quality ◽  
Quantum Devices ◽  
Wafer Scale ◽  
Transmission Electron ◽  
Controllable Growth

Controllable growth of wafer-scale in-plane nanowires (NWs) is a prerequisite for achieving addressable and scalable NW-based quantum devices. Here, by introducing molecular beam epitaxy on patterned Si structures, we demonstrate the wafer-scale epitaxial growth of site-controlled in-plane Si, SiGe, and Ge/Si core/shell NW arrays on Si (001) substrate. The epitaxially grown Si, SiGe, and Ge/Si core/shell NW are highly homogeneous with well-defined facets. Suspended Si NWs with four {111} facets and a side width of about 25 nm are observed. Characterizations including high resolution transmission electron microscopy (HRTEM) confirm the high quality of these epitaxial NWs.

CHARACTERIZATION AND ELECTRICAL PROPERTIES OF ALIGNED CARBON NANOTUBES WITH HIGH ASPECT RATIO

2011 ◽  
Vol 10 (01n02) ◽  
pp. 23-28
Author(s):  
RAVI BHATIA ◽  
V. PRASAD ◽  
M. REGHU
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Aspect Ratio ◽  
Multiwall Carbon Nanotubes ◽  
High Quality ◽  
Transmission Electron Microscopy Analysis ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
High Degree

High-quality multiwall carbon nanotubes (MWNTs) were produced by a simple one-step technique. The production of MWNTs was based on thermal decomposition of the mixture of a liquid phase organic compound and ferrocene. High degree of alignment was noticed by scanning electron microscopy. The aspect ratio of as-synthesized MWNTs was quite high (more than 4500). Transmission electron microscopy analysis showed the presence of the catalytic iron nanorods at various lengths of MWNTs. Raman spectroscopy was used to know the quality of MWNTs. The ratio of intensity of the G-peak to the D-peak was very high which revealed high quality of MWNTs. Magnetotransport studies were carried out at low temperature and a negative MR was noticed.

Defect-Engineered Graded GexSi1-x Buffers on Si (001) with Extreme Low Threading Dislocation Density

1995 ◽  
Vol 378 ◽  
Author(s):  
G. Kissinger ◽  
T. Morgenstern ◽  
G. Morgenstern ◽  
H. B. Erzgräber ◽  
H. Richter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Dislocation Density ◽  
Threading Dislocation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Threading Dislocation Density

AbstractStepwise equilibrated graded GexSii-x (x≤0.2) buffers with threading dislocation densities between 102 and 103 cm−2 on the whole area of 4 inch silicon wafers were grown and studied by transmission electron microscopy, defect etching, atomic force microscopy and photoluminescence spectroscopy.

Effectiveness and Reliability of Metal Diffusion Barriers for Copper Interconnects

1995 ◽  
Vol 403 ◽  
Author(s):  
G. Bai ◽  
S. Wittenbrock ◽  
V. Ochoa ◽  
R. Villasol ◽  
C. Chiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Chemical Vapor ◽  
Diffusion Barriers ◽  
Copper Interconnects ◽  
Time To Failure ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

AbstractCu has two advantages over Al for sub-quarter micron interconnect application: (1) higher conductivity and (2) improved electromigration reliability. However, Cu diffuses quickly in SiO2and Si, and must be encapsulated. Polycrystalline films of Physical Vapor Deposition (PVD) Ta, W, Mo, TiN, and Metal-Organo Chemical Vapor Deposition (MOCVD) TiN and Ti-Si-N have been evaluated as Cu diffusion barriers using electrically biased-thermal-stressing tests. Barrier effectiveness of these thin films were correlated with their physical properties from Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Secondary Electron Microscopy (SEM), and Auger Electron Spectroscopy (AES) analysis. The barrier failure is dominated by “micro-defects” in the barrier film that serve as easy pathways for Cu diffusion. An ideal barrier system should be free of such micro-defects (e.g., amorphous Ti-Si-N and annealed Ta). The median-time-to-failure (MTTF) of a Ta barrier (30 nm) has been measured at different bias electrical fields and stressing temperatures, and the extrapolated MTTF of such a barrier is > 100 year at an operating condition of 200C and 0.1 MV/cm.

Sign in / Sign up

Export Citation Format

Share Document