scholarly journals Crystalline Silicon Spalling as a Direct Application of Temperature Effect on Semiconductors’ Indentation

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1020
Author(s):  
Maha M. Khayyat
Keyword(s):  
Room Temperature ◽  
Crystalline Silicon ◽  
Liquid Nitrogen Temperature ◽  
Plastic Substrate ◽  
Single Fracture ◽  
Large Area ◽  
Surface Layers ◽  
Silicon Devices ◽  
Wide Range ◽  
Continuous Surface

Kerf-less removal of surface layers of photovoltaic materials including silicon is an emerging technology by controlled spalling technology. The method is extremely simple, versatile, and applicable to a wide range of substrates. Controlled spalling technology requires a stressor layer, such as Ni, to be deposited on the surface of a brittle material; then, the controlled removal of a continuous surface layer can be performed at a predetermined depth by manipulating the thickness and stress of the Ni layer, introducing a crack near the edge of the substrate, and mechanically guiding the crack as a single fracture front across the surface. However, spalling Si(100) at 300 K (room temperature RT) introduced many cracks and rough regions within the spalled layer. These mechanical issues make it difficult to process these layers of Si(100) for PV, and in other advanced applications, Si does not undergo phase transformations at 77 K (Liquid Nitrogen Temperature, LNT); based on this fact, spalling of Si(100) has been carried out. Spalling of Si(100) at LNT improved material quality for further designed applications. Mechanical flexibility is achieved by employing controlled spalling technology, enabling the large-area transfer of ultrathin body silicon devices to a plastic substrate at room temperature.

scholarly journals Giant power factors in p- and n-type large-area graphene films on a flexible plastic substrate

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Kaito Kanahashi ◽  
Masatou Ishihara ◽  
Masataka Hasegawa ◽  
Hiromichi Ohta ◽  
Taishi Takenobu
Keyword(s):  
Vapor Deposition ◽  
Large Scale ◽  
Chemical Vapor ◽  
Plastic Substrate ◽  
Large Area ◽  
Flexible Materials ◽  
Graphene Films ◽  
Wide Range ◽  
Carrier Doping ◽  
Electron Carriers

Abstract This study reports on the thermoelectric properties of large-area graphene films grown by chemical vapor deposition (CVD) methods. Using the electric double layer gating technique, both the continuous doping of hole or electron carriers and modulation of the Fermi energy are achieved, leading to wide-range control of the Seebeck coefficient and electrical conductivity. Consequently, the maximum power factors of the CVD-grown large-area graphene films are 6.93 and 3.29 mW m–1 K–2 for p- and n-type carrier doping, respectively. These results are the best values among large-scale flexible materials, such as organic conducting polymers and carbon nanotubes, suggesting that CVD-grown large-area graphene films have potential for thermoelectric applications.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

1991 ◽  
Vol 30 (01) ◽  
pp. 35-39 ◽  
Author(s):  
H. S. Durak ◽  
M. Kitapgi ◽  
B. E. Caner ◽  
R. Senekowitsch ◽  
M. T. Ercan
Keyword(s):  
Soft Tissue ◽  
Room Temperature ◽  
Normal Subjects ◽  
Left Testis ◽  
Wide Range ◽  
Activity Ratios ◽  
The Right ◽  
Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

A novel low cost texturization method for large area commercial mono-crystalline silicon solar cells

2006 ◽  
Vol 90 (20) ◽  
pp. 3557-3567 ◽  
Author(s):  
U. Gangopadhyay ◽  
K.H. Kim ◽  
S.K. Dhungel ◽  
U. Manna ◽  
P.K. Basu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Crystalline Silicon ◽  
Low Cost ◽  
Silicon Solar Cells ◽  
Large Area ◽  
Crystalline Silicon Solar Cells

scholarly journals The Growth of Semiconductor Thin Films Studied by RHEED

1990 ◽  
Vol 43 (5) ◽  
pp. 583
Author(s):  
GL Price
Keyword(s):  
Thin Films ◽  
Surface Science ◽  
High Vacuum ◽  
High Energy ◽  
Ultra High Vacuum ◽  
Large Area ◽  
Growth Modes ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Recent Developments

Recent developments in the growth of semiconductor thin films are reviewed. The emphasis is on growth by molecular beam epitaxy (MBE). Results obtained by reflection high energy electron diffraction (RHEED) are employed to describe the different kinds of growth processes and the types of materials which can be constructed. MBE is routinely capable of heterostructure growth to atomic precision with a wide range of materials including III-V, IV, II-VI semiconductors, metals, ceramics such as high Tc materials and organics. As the growth proceeds in ultra high vacuum, MBE can take advantage of surface science techniques such as Auger, RHEED and SIMS. RHEED is the essential in-situ probe since the final crystal quality is strongly dependent on the surface reconstruction during growth. RHEED can also be used to calibrate the growth rate, monitor growth kinetics, and distinguish between various growth modes. A major new area is lattice mismatched growth where attempts are being made to construct heterostructures between materials of different lattice constants such as GaAs on Si. Also described are the new techniques of migration enhanced epitaxy and tilted superlattice growth. Finally some comments are given On the means of preparing large area, thin samples for analysis by other techniques from MBE grown films using capping, etching and liftoff.

Porphyrin-Catalyzed Oxidation of N-Substituted Tetrahydroisoquinolines to Dihydroisoquinolones

Synlett ◽  
2021 ◽  
Author(s):  
Ao Li ◽  
Bin Pan ◽  
Mu Chao ◽  
Na Wang ◽  
Yu-Long Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Air Atmosphere ◽  
Wide Range ◽  
Convenient Route ◽  
Catalyzed Oxidation

A visible-light-induced direct α-oxygenation of N-substituted tetrahydroisoquinoline derivatives has been successfully developed. Metalloporphyrin (ZnTPP) has been identified as an effective and inexpensive photocatalyst for this transformation with a wide range of substrates. This protocol provides a convenient route to afford the desired products in moderate to good yields at room temperature under air atmosphere.

scholarly journals Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jinchao Tong ◽  
Fei Suo ◽  
Tianning Zhang ◽  
Zhiming Huang ◽  
Junhao Chu ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
High Performance ◽  
Room Temperature ◽  
Spectral Band ◽  
High Capacity ◽  
Terahertz Wave ◽  
Semiconductor Surface ◽  
Wide Range ◽  
Low Sensitivity ◽  
Air Interfaces

AbstractHigh-performance uncooled millimetre and terahertz wave detectors are required as a building block for a wide range of applications. The state-of-the-art technologies, however, are plagued by low sensitivity, narrow spectral bandwidth, and complicated architecture. Here, we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature operation. By making a nanogroove array in the grown InSb layer, strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb–air interfaces, which results in significant improvement in detecting performance. A noise equivalent power (NEP) of 2.2 × 10−14 W Hz−1/2 or a detectivity (D*) of 2.7 × 1012 cm Hz1/2 W−1 at 1.75 mm (0.171 THz) is achieved at room temperature. By lowering the temperature to the thermoelectric cooling available 200 K, the corresponding NEP and D* of the nanogroove device can be improved to 3.8 × 10−15 W Hz−1/2 and 1.6 × 1013 cm Hz1/2 W−1, respectively. In addition, such a single device can perform broad spectral band detection from 0.9 mm (0.330 THz) to 9.4 mm (0.032 THz). Fast responses of 3.5 µs and 780 ns are achieved at room temperature and 200 K, respectively. Such high-performance millimetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications, walk-through security, biological diagnosis, spectroscopy, and remote sensing. In addition, the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

scholarly journals Ab initiostructure determination of nanocrystals of organic pharmaceutical compounds by electron diffraction at room temperature using a Timepix quantum area direct electron detector

2016 ◽  
Vol 72 (2) ◽  
pp. 236-242 ◽  
Author(s):  
E. van Genderen ◽  
M. T. B. Clabbers ◽  
P. P. Das ◽  
A. Stewart ◽  
I. Nederlof ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Direct Methods ◽  
Liquid Nitrogen Temperature ◽  
High Dynamic Range ◽  
Electron Diffraction Data ◽  
High Signal

Until recently, structure determination by transmission electron microscopy of beam-sensitive three-dimensional nanocrystals required electron diffraction tomography data collection at liquid-nitrogen temperature, in order to reduce radiation damage. Here it is shown that the novel Timepix detector combines a high dynamic range with a very high signal-to-noise ratio and single-electron sensitivity, enablingab initiophasing of beam-sensitive organic compounds. Low-dose electron diffraction data (∼0.013 e− Å−2 s−1) were collected at room temperature with the rotation method. It was ascertained that the data were of sufficient quality for structure solution using direct methods using software developed for X-ray crystallography (XDS,SHELX) and for electron crystallography (ADT3D/PETS,SIR2014).

NOHSO4/HF – A Novel Etching System for Crystalline Silicon

2007 ◽  
Vol 62 (11) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sebastian Patzig ◽  
Gerhard Roewer ◽  
Edwin Kroke ◽  
Ingo över
Keyword(s):  
Gas Phase ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Etching Solution ◽  
Wide Range ◽  
Ft Ir ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Etching System

Solutions consisting of HF - NOHSO4 - H2SO4 exhibit a strong reactivity towards crystalline silicon which is controlled by the concentrations of the reactive species HF and NO+. Selective isotropic and anisotropic wet chemical etching with these solutions allows to generate a wide range of silicon surface morphology patterns. Traces of Ag+ ions stimulate the reactivity and lead to the formation of planarized (polished) silicon surfaces. Analyses of the silicon surface, the etching solution and the gas phase were performed with scanning electron microscopy (SEM), DR/FT-IR (diffusive reflection Fourier transform infra-red), FT-IR, Raman and NMR spectroscopy, respectively. It was found that the resulting silicon surface is hydrogen-terminated. The gas phase contains predominantly SiF4, NO and N2O. Furthermore, NH4+ is produced in solution. The study has confirmed the crucial role of nitrosyl ions for isotropic wet chemical etching processes. The novel etching system is proposed as an effective new way for selective surface texturing of multi- and monocrystalline silicon. A high etching bath service lifetime, besides a low contamination of the etching solution with reaction products, provides ecological and economical advantages for the semiconductor and solar industry.

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