Amorphous Semiconductor Multilayer Structures: Interface and Layer Thickness Effects in Photoluminescence

1985 ◽  
Vol 49 ◽  
Author(s):  
T. Tiedje
Keyword(s):  
Amorphous Semiconductor ◽  
Amorphous Semiconductors ◽  
Multilayer Structures ◽  
Length Scale ◽  
Structural Perfection ◽  
New Developments ◽  
Transmission Electron ◽  
High Degree ◽  
Highly Uniform ◽  
Superlattice Period

A number of new developments have occurred recently in research on the synthesis and properties of amorphous semiconductor multilayer structures (“amorphous superlattices”) since the discovery of this class of materials in 1983.1 This and more recentwork have shown that tetrahedrally bonded amorphous semiconductors can be fabricated in the form of multilayer structures, with highly uniform layers and atomically abrupt interfaces. The remarkably high degree of structural perfection in these materials on the length scale of the superlattice period (> 5A) has been demonstrated by transmission electron microscopy.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Investigation of ultra-thin films of YBa2Cu3O7−δ grown on MgO

1990 ◽  
Vol 48 (4) ◽  
pp. 6-7
Author(s):  
S.K. Streiffer ◽  
C.B. Eom ◽  
J.C. Bravman ◽  
T.H. Geballet
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
Multilayer Structures ◽  
Rf Power ◽  
Oxygen Loss ◽  
Transmission Electron ◽  
Single Target ◽  
Mtorr Argon

The study of very thin (<15 nm) YBa2Cu3O7−δ (YBCO) films is necessary both for investigating the nucleation and growth of films of this material and for achieving a better understanding of multilayer structures incorporating such thin YBCO regions. We have used transmission electron microscopy to examine ultra-thin films grown on MgO substrates by single-target, off-axis magnetron sputtering; details of the deposition process have been reported elsewhere. Briefly, polished MgO substrates were attached to a block placed at 90° to the sputtering target and heated to 650 °C. The sputtering was performed in 10 mtorr oxygen and 40 mtorr argon with an rf power of 125 watts. After deposition, the chamber was vented to 500 torr oxygen and allowed to cool to room temperature. Because of YBCO’s susceptibility to environmental degradation and oxygen loss, the technique of Xi, et al. was followed and a protective overlayer of amorphous YBCO was deposited on the just-grown films.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

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.

Fabrication and characterization of highly textured (Bi,Pb)2Sr2Ca2Cu3Ox superconducting ceramics using high magnetic field and cold isostatic pressing

1995 ◽  
Vol 10 (10) ◽  
pp. 2433-2443 ◽  
Author(s):  
Wai Lo ◽  
R. Stevens ◽  
R. Doyle ◽  
A.M. Campbell ◽  
W.Y. Liang
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Cold Isostatic Pressing ◽  
Sintered Ceramic ◽  
Grain Alignment ◽  
Isostatic Pressing ◽  
Transmission Electron ◽  
Superconducting Ceramics ◽  
High Degree

High textured (Bi,Pb)2Sr2Ca2Cu3Ox ceramics have been fabricated by aligning deflocculated flakes of (Bi,Pb)2Sr2Ca2Cu3Ox suspended in an organic medium by means of a high de magnetic field (6 T) at room temperature followed by cold isostatic pressing. The proportion of the (Bi,Pb)2Sr2Ca2Cu3Ox phase in the precursor powder was carefully controlled, and the characteristics of the powder, such as size distribution and morphology, were determined. A high degree of grain alignment was found in the specimens after the magnetic alignment, although the bulk density of the materials was low. Cold isostatic pressing substantially increased the density of the magnetically prealigned specimens which also resulted in a slight decrease in the degree of grain alignment. This minor realignment was found to be due to the various kinds of processing defects that appeared in the specimens during compaction due to the grinding and cracking of the grains and their interlocking. The microstructural and superconducting properties of the sintered ceramic have been studied using texture goniometry, high resolution scanning electron microscopy, transmission electron microscopy, ac magnetic susceptometry, and critical current measurements.

Low-temperature route to nanoscale P3N5 hollow spheres

2003 ◽  
Vol 18 (10) ◽  
pp. 2359-2363 ◽  
Author(s):  
Hongzhou Gu ◽  
Yunle Gu ◽  
Zhefeng Li ◽  
Yongcheng Ying ◽  
Yitai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hollow Spheres ◽  
Molar Ratio ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Influence Of Temperature On ◽  
Wide Gap ◽  
20 Nm ◽  
High Degree

Nanoscale hollow spheres of amorphous phosphorus nitride (P3N5) were synthesized by reacting PCl3 with NaN3 at 150–250 °C. Transmission electron microscope images show that the hollow spheres have a diameter of 150–350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 °C. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for P:N. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265–315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.

scholarly journals A novel copper precursor for electron beam induced deposition

2018 ◽  
Vol 9 ◽  
pp. 1220-1227 ◽  
Author(s):  
Caspar Haverkamp ◽  
George Sarau ◽  
Mikhail N Polyakov ◽  
Ivo Utke ◽  
Marcos V Puydinger dos Santos ◽  
...  
Keyword(s):  
Electron Beam ◽  
Optical Transmission ◽  
Pure Copper ◽  
Dielectric Behavior ◽  
Copper Oxidation ◽  
Transmission Electron ◽  
Sum Formula ◽  
Electron Beam Induced Deposition ◽  
High Degree ◽  
Good Agreement

A fluorine free copper precursor, Cu(tbaoac)2 with the chemical sum formula CuC16O6H26 is introduced for focused electron beam induced deposition (FEBID). FEBID with 15 keV and 7 nA results in deposits with an atomic composition of Cu:O:C of approximately 1:1:2. Transmission electron microscopy proved that pure copper nanocrystals with sizes of up to around 15 nm were dispersed inside the carbonaceous matrix. Raman investigations revealed a high degree of amorphization of the carbonaceous matrix and showed hints for partial copper oxidation taking place selectively on the surfaces of the deposits. Optical transmission/reflection measurements of deposited pads showed a dielectric behavior of the material in the optical spectral range. The general behavior of the permittivity could be described by applying the Maxwell–Garnett mixing model to amorphous carbon and copper. The dielectric function measured from deposited pads was used to simulate the optical response of tip arrays fabricated out of the same precursor and showed good agreement with measurements. This paves the way for future plasmonic applications with copper-FEBID.

Transmission Electron Microscopic Study Of Heteroepitaxial Mechanism Of Cvd-Dlamond Grown On Pt(Lll) Substrate.

1999 ◽  
Vol 5 (S2) ◽  
pp. 170-171
Author(s):  
Guofu Zhou ◽  
Yoshizo Takai ◽  
Ryuichi Shimizu
Keyword(s):  
Diamond Film ◽  
Electronic Devices ◽  
Chemical Properties ◽  
Atomic Scale ◽  
Diamond Growth ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Single Crystal Diamond ◽  
High Degree ◽  
Novel Devices

Owing to its unique and outstanding physical-chemical properties, diamond is considered to be one of the most important potential materials for applications such as in mechanical, optical, thermal, and electronic devices. Among them, the most attractive application of diamond would be a semiconductor for high temperature and high power electronic devices. To realize such novel devices, a high quality of defect-free single-crystal diamond film is required. Recently, continuous diamond films are found to be able to grow on Pt(lll) substrate. Since the diamond film synthesized on Pt shows a high degree of epitaxy, this approach has drawn the attention of reseafchers in this field and some research results have been reported. However, the heteroepitaxial mechanism is still to be elucidated; in particular, why does diamond grow heteroepitaxially on the Pt substrate and how do the atoms align in the interface between diamond and the Pt substrate? In order to solve those problems, it is very necessary to study the diamond growth mechanism on an atomic scale.

Biological Behavior of Canine Acanthomatous Ameloblastoma Assessed With Computed Tomography and Histopathology: A Comparative Study

2020 ◽  
Vol 37 (3) ◽  
pp. 126-132
Author(s):  
Stephanie Goldschmidt ◽  
Cynthia Bell ◽  
Kenneth Waller ◽  
Scott Hetzel ◽  
Jason W. Soukup
Keyword(s):  
Computed Tomography ◽  
Diagnostic Imaging ◽  
Bone Destruction ◽  
Biological Behavior ◽  
Diagnostic Tools ◽  
Tumor Invasiveness ◽  
Computed Tomographic ◽  
High Degree ◽  
Highly Uniform

Canine acanthomatous ameloblastoma (CAA) appears to have variable biological behavior with some tumors presenting with slow growth and minimal bone loss while others grow rapidly and cause severe cancellous and cortical bone destruction. The primary aim of the study is to elucidate if variations (grades) of CAA can be identified based on both histological and diagnostic imaging indices, and to compare markers of more aggressive behavior between these 2 commonly used diagnostic tools. This study evaluated 45 cases of CAA and confirmed that there is high degree of variability in tumor invasiveness as measured with computed tomography, with predominantly intraosseous tumors being significantly associated with more invasive behavior. However, the analysis also identified that there was very little correlation between computed tomographic and histological appearance of the tumor. CAA tends to have a highly uniform and predictable histological pattern, with tumors that aggressively invade bone (as seen on CT) not showing features of atypia that might be helpful in predicting the biological behavior of the neoplastic cells. Thus, reliance on diagnostic imaging as a measure of biological behavior is recommended for treatment planning as well as possible creation of a variant/grading scheme. Prospective studies are required to evaluate if differing variants of CAA as based on diagnostic imaging should be treated differently, and how this would affect long term clinical outcome.

A Quantitative Model for the Metastable Defect Creation in Amorphous Semiconductors by Kev-Electron Irradiation

1994 ◽  
Vol 336 ◽  
Author(s):  
A. Scholz ◽  
B. Schröder ◽  
H. Oechsner
Keyword(s):  
Energy Dissipation ◽  
Electron Irradiation ◽  
Quantitative Agreement ◽  
Quantitative Model ◽  
Amorphous Semiconductor ◽  
Amorphous Semiconductors ◽  
Experimental Results ◽  
Defect Creation ◽  
Hydrogenated Amorphous ◽  
Metastable Defect

ABSTRACTThe interaction mechanisms of keV-electrons with the hydrogenated Amorphous semiconductor are briefly discussed and the differences to the metastable defect creation by photons are set out. Based on the knowlegde of the energy dissipation mechanisms of keV-electrons in the hydrogenated Amorphous semiconductor, a model for the creation of metastable defects by keV-electron irradiation is developed and its quantitative agreement with the experimental results is shown.

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