A Channeling Study on Mg Implanted InSb Single Crystals

1983 ◽  
Vol 27 ◽  
Author(s):  
H.W. Alberts
Keyword(s):  
Melting Point ◽  
Radiation Damage ◽  
Linear Dependence ◽  
Room Temperature ◽  
Annihilation Rate ◽  
Sharp Reduction ◽  
Complex Defect ◽  
Annealing Effects ◽  
Implantation Process ◽  
Substrate Temperatures

ABSTRACTProton and α-particle channeling were used to study the radiation damage caused by the implantation of 160 keV Mg ions in InSb. The implantations took place at various substrate temperatures ranging from room temperature to temperatures just below the melting point and doses ranging from 5.1013 to 1.1016 Mg+ cm−2. The isochronal annealing of the room temperature implanted crystals started at 200°C and damage could not be completely removed even at temperatures just below the melting point. For crystals implanted at elevated substrate temperatures no annealing effects during implantation occured up to 400°C. Above 400°C a sharp reduction of damage indicates that the rate of formation of more complex defect configurations during the implantation process becomes smaller than the annihilation rate of the vacancy-interstitial pairs. A non-linear dependence exists between the degree of radiation damage in the InSb lattice and the implanted dose.

High Energy Ion Beam Annealing in Implanted CdTe

1988 ◽  
Vol 100 ◽  
Author(s):  
S. P. Withrow ◽  
A. Lusnikov ◽  
H. J. Jiménez-Gonz´lez- ◽  
G. Dresselhaus
Keyword(s):  
Single Crystals ◽  
Ion Beam ◽  
High Energy ◽  
Near Surface ◽  
Energy Beam ◽  
Annealing Effects ◽  
Lattice Damage ◽  
Implantation Process ◽  
Substrate Temperatures ◽  
Cu Ions

ABSTRACTThe annealing effects of a high energy beam of Cu ions on implanted CdTe crystals are studied. Single crystals of CdTe have been implanted with Eu (energy 60 keV, fluence 1 × 1016 cm−2) at substrate temperatures of 25°C, and 400°C. Lattice damage introduced by the implantation process was measured by Rutherford backscattering. The samples were then implanted with high energy Cu ions (energy 3.5 MeV, fluence 0.5 × 1016 cm−2) at substrate temperatures of 25°C and 200°C. Channeling spectra from these samples indicate a reduction in the near-surface lattice damage as a result of the Cu implantation that can be unambiguously separated from the external heating of the substrate.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Novel Chemical Route to Size-Controlled Ta(0) and Ru-Ta Nanoparticles in Ionic Liquids

2012 ◽  
Vol 1473 ◽  
Author(s):  
Inga S. Helgadottir ◽  
Philippe P. Arquillière ◽  
Paul S. Campbell ◽  
Catherine C. Santini ◽  
P.-H. Haumesser
Keyword(s):  
Ionic Liquids ◽  
Melting Point ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Chemical Route ◽  
High Interest ◽  
Microelectronics Industry ◽  
Synthetic Routes ◽  
Size Controlled

ABSTRACTMetallic nanoparticles under 10 nm are of particular interest for the microelectronics industry. However, there is a lack of convenient synthetic routes to control their size Oxophilic metals, such as Ta, are also of high interest, however, the high oxophilicity and melting point makes the synthesis of such nanoparticles challenging. Making use of imidazolium-based ionic liquids, monodisperse zero-valent tantalum nanoparticles (Ta(0)NPs) have been successfully synthesised at room temperature by reduction of tris(neopentyl)neopentylidenetantalum(V). Furthermore; well size-controlled bimetallic Ru-Ta NPs have also been synthesized.

The Characteristic of the La3Ga5SiO14 Single Crystal Grown by Vertical Bridgman Method in Ar Atmosphere

2006 ◽  
Vol 510-511 ◽  
pp. 842-845 ◽  
Author(s):  
Noriko Bamba ◽  
Kentaro Kato ◽  
Toshinori Taishi ◽  
Takayuki Hayashi ◽  
Keigo Hoshikawa ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Color Change ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Piezoelectric Constant ◽  
Interstitial Oxygen ◽  
Vertical Bridgman

Langasite (La3Ga5SiO14: denoted by LGS) single crystal is one of the lead free piezoelectric materials with high piezoelectricity that is maintained up to its melting point (1470°C). Although LGS single crystals have usually been grown by Czochralski (CZ) method in oxygen contained atmosphere to prevent evaporation of Ga, they were grown by the vertical Bridgman (VB) method in Ar atmosphere without oxygen, and their properties were evaluated in this work. Transparent and colorless LGS single crystals were successfully obtained without Ga evaporation by the VB method in Ar atmosphere, and their resistivity at room temperature was much higher than that grown by conventional CZ method. Piezoelectric constant d11 of the crystal grown by the VB method was 6 x 10-12 C/N, which was close to that of the crystal grown by CZ method. The colorless transparent LGS single crystal turned to orange and its resistivity decreased by annealing in air. Since an orange-colored transparent LGS single crystal has been grown by conventional CZ method, this indicates that color change and the resistivity decrease of LGS crystal is caused by extra interstitial oxygen atoms in the crystal.

Annealing effects on a-SiC:H and a-SiC:H(F) thin films deposited by PECVD at room temperature

1995 ◽  
Vol 261 (1-2) ◽  
pp. 192-201 ◽  
Author(s):  
Dong S. Kim ◽  
Young H. Lee
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Annealing Effects

scholarly journals Radiation damage effects on protein conformation at room temperature and 100K

2014 ◽  
Vol 70 (a1) ◽  
pp. C344-C344
Author(s):  
Silvia Russi ◽  
Shawn Kann ◽  
Henry van den Bedem ◽  
Ana M. González
Keyword(s):  
Data Collection ◽  
Radiation Damage ◽  
Crystal Structures ◽  
Room Temperature ◽  
Relative Rate ◽  
Absorbed Dose ◽  
Conformational Ensemble ◽  
Data Sets ◽  
Cryogenic Temperatures ◽  
Full Data

Protein crystallography data collection at synchrotrons today is routinely carried out at cryogenic temperatures to mitigate radiation damage to the crystal. Although damage still takes place, at 100 K and below, the immobilization of free radicals increases the lifetime of the crystals by orders of magnitude. Increasingly, experiments are carried out at room temperature. The lack of adequate cryo-protectants, the induced lattice changes or internal disorders during the cooling process, and the convenience of collecting data directly from the crystallization plates, are some of the reasons. Moreover, recent studies have shown that flash-freezing affects the conformational ensemble of crystal structures [1], and can hide important functional mechanisms from observation [2]. While there has been a considerable amount of effort in studying radiation damage at cryo-temperatures, its effects at room temperature are still not well understood. We investigated the effects of data collection temperature on secondary local damage to the side chain and main chain from different proteins. Data were collected from crystals of thaumatin and lysozyme at 100 K and room temperature. To carefully control the total absorbed dose, full data sets at room temperature were assembled from a few diffraction images per crystal. Several data sets were collected at increasing levels of absorbed dose. Our analysis shows that while at cryogenic temperatures, radiation damage increases the conformational variability, _x0004_at room temperature it has the opposite effect_x0005_. We also observed that disulfide bonds appear to break up at a different relative rate at room temperature, perhaps because of a more active repair mechanism. Our analysis suggests that elevated conformational heterogeneity in crystal structures at room temperature is observed despite radiation damage, and not as a result thereof.

RBS/Channeling Characterization of Ba Implanted Mg

1992 ◽  
Vol 279 ◽  
Author(s):  
R. C. Da Silva ◽  
Th. Hauser ◽  
A. A. Melo ◽  
J. C. Soares ◽  
M. F. Da Silva ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Room Temperature ◽  
Surface Segregation

ABSTRACTThe behaviour of 300 keV Ba ions implanted at room temperature with doses between 1015 and 1017 cm−2 in Mg single crystal and foils was investigated. The results show that the Ba ions do not occupy substitutions sites in Mg, either after the implantation or the annealing treatments. However, pronounced migration of Ba to the surface is observed above 380 °C. The remaining fraction overlaps with the aa-implanted distribution and forms small precipitates. This behaviour is not correlated with the recovery of the Mg lattice which is already complete at about 250 °C. The surface segregation of Ba delays the evaporation of Mg to temperatures near the melting point.

Magnetoresistance and Structure of Granular Co/Ag Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
Mary Beth Stearns ◽  
Yuanda Cheng
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Room Temperature ◽  
Magnetization Measurements ◽  
X Ray ◽  
Conduction Electrons ◽  
Low Field ◽  
Co Concentration ◽  
Microscopy Techniques ◽  
Substrate Temperatures

ABSTRACTSeveral series of CoxAg1-x granular thin films (-3000Å) were fabricated by coevapora-tion of Co and Ag in a dual e-beam UHV deposition system at varying substrate temperatures. These films have low field magnetoresistance values as large as 31% at room temperature and 65% at liquid N2 temperature. The structure of the films was determined using magnetization measurements as well as x-ray and various electron microscopy techniques. The composition was determined using Rutherford backscattering spectroscopy. The Magnetoresistance was measured at both room and liquid N2 temperatures.We deduce from the magnetization and RBS Measurements that the films consist of Co globules embedded in a Ag Matrix and that there is no appreciable mixing of the Co and Ag atoms in the films deposited at substrate temperatures ≥ 400°K. The size of the Co globules is seen to increase with increasing Co concentration and the maximum magnetoresistance occurs in those films having the smallest Ag thickness which provides magnetic isolation of the Co globules.We suggest that the large magnetoresistance of these films arises from the same mechanism which causes the low field magnetoresistance in pure ferromagnets, namely, the scattering of the highly polarized d conduction electrons of the Co at magnetic boundaries. The large increase in the room temperature magnetoresistance of the CO/Ag films as compared to those of pure 3d ferromagnetic films is due to the distance between the magnetic boundaries being reduced to a few nanometers, because of the small size of the single domain Co globules, as compared to a few microns in 3d ferromagnets.

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