ION CHANNELING AND PIXE STUDIES OF S IMPLANTATION IN GaAs

1992 ◽  
Vol 02 (02) ◽  
pp. 151-159
Author(s):  
LIU SHIJIE ◽  
WANG JIANG ◽  
HU ZAOHUEI ◽  
XIA ZHONGHUONG ◽  
GAO ZHIGIANG ◽  
...  
Keyword(s):  
Room Temperature ◽  
Dislocation Loops ◽  
Good Recovery ◽  
Electrical Measurements ◽  
X Ray ◽  
Defect Complexes ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Activation Efficiency ◽  
Very High

GaAs (100) crystals were implanted with 100 keV S+ to a dose of 3×1015 cm−2 in a nonchanneling direction at room temperature, and treated with rapid thermal annealing (RTA). He+ Rutherford backscattering and particle-induced X-ray emission in channeling mode in combination with transmission electron microscopy (TEM) were used to study the damage and the lattice location of S atoms. It is revealed that the RTA at 950 °C for 10 sec has resulted in a very good recovery of crystallinity with a few residual defects in the form of dislocation loops, and a very high substitutionality (~90%). The activation efficiency and the Hall mobility of the implanted samples are found to be low after the electrical measurements. Based on these results an extended dopant diffusion effect for the residual defects and a correlation between the electrical properties and defect complexes are suggested.

Two-step oxygen injection process for growing ZnO nanorods

2003 ◽  
Vol 18 (12) ◽  
pp. 2837-2844 ◽  
Author(s):  
Yung-Kuan Tseng ◽  
Hsu-Cheng Hsu ◽  
Wen-Feng Hsieh ◽  
Kuo-Shung Liu ◽  
I-Cherng Chen
Keyword(s):  
Oxygen Concentration ◽  
Room Temperature ◽  
Zno Nanorods ◽  
Oxygen Flow Rate ◽  
X Ray Diffraction ◽  
Oxygen Injection ◽  
X Ray ◽  
Injection Process ◽  
Transmission Electron ◽  
Very High

Uniform hexagonal prismatic zinc oxide rods were grown over the entire alumina substrate at 550°C using a two-step oxygen injection process, whether the substrates were coated with a catalyst or not. X-ray diffraction showed that all of the depositions exhibited a preferred orientation in the (002) plane. The influence of oxygen concentration was investigated by changing the oxygen flow rate. Oxygen concentration affected the size of ZnO nanorods, especially the diameter. The ZnO nanorods were further checked using high-resolution transmission electron microscopy, photoluminescence, Raman spectroscopy, and room-temperature ultraviolet lasing. The results showed that the rods were single crystals and had excellent optical properties. By observing the growth process, we found that the diameter increased slowly, but the longitudinal growth rate was very high. The growth of ZnO nanorods revealed that the uniform hexagonal prismatic ZnO nanorods were synthesized through vapor deposition growth and a self-catalyzed vapor–liquid–solid (VLS) process.

The Microstructure of Transiently Annealed Donor Implants in GaAs

1984 ◽  
Vol 35 ◽  
Author(s):  
M.A. Shahid ◽  
R. Bensalem ◽  
B.J. Sealy
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electrical Activity ◽  
Room Temperature ◽  
Dislocation Loops ◽  
Electrical Measurements ◽  
Ion Energy ◽  
Transmission Electron

ABSTRACTUndoped SI (100) GaAs has been implanted with selenium and tin ions at room temperature at an ion energy of 300 keV and using ion dose in the range 1 × 1014 to 1 × 1015 ions cm−2. Transient annealing at 1000°C and above has been studied using electrical measurements and transmission electron microscopy. The results show that tin implanted samples have comparatively higher values of electrical activity and mobility than those implanted with selenium ions. A difference in the microstructure of these two implants was observed. Selenium implanted samples show dislocation lines and loops possessing 1/2<110> Burgers vectors while tin implanted GaAs contains dislocation loops of 1/2<110> and 1/3<111> types and also dislocation lines having 1/2<110> Burgers vectors. Both types of defect in tin implanted samples are decorated with precipitates.

scholarly journals Identification of unexpected hydrides in Mg–20 wt% Dy alloy by high-brilliance synchrotron radiation

2011 ◽  
Vol 45 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Weimin Gan ◽  
Yuanding Huang ◽  
Lei Yang ◽  
Karl Ulrich Kainer ◽  
Miao Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Binary Phase Diagram ◽  
Precipitate Phase ◽  
Synchrotron Diffraction ◽  
X Ray ◽  
The Poor ◽  
Transmission Electron ◽  
Very High ◽  
Scanning Electron

An unexpected precipitate phase was observed in Mg–20 wt% Dy alloy, with a cuboid morphology not compatible with any shown in the Mg–Dy binary phase diagram. As observed by scanning electron microscopy and energy-dispersive X-ray analysis, the ratio of atomic percent of Dy to Mg is very high in these particles, probably largely because of the poor spatial resolution of that technique but already showing the mismatch with any previously characterized Mg–Dy compound. High-brilliance synchrotron diffraction and transmission electron microscopy experiments confirmed that these particles are composed of DyH2. They are formed during sample preparation at room temperature when hydrogen-containing sources such as water are used.

Structural and Optical Property Investigations on Mg-Alloying in Epitaxial Zinc Oxide Films on Sapphire

1999 ◽  
Vol 595 ◽  
Author(s):  
A.K. Sharma ◽  
C. Jin ◽  
A. Kvit ◽  
J. Narayan ◽  
J.F. Muth ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Channeling ◽  
Zinc Oxide Films ◽  
Transmission Electron ◽  
Potential Applications ◽  
Post Deposition

AbstractWe have synthesized single-crystal epitaxial MgZnO films by pulsed-laser deposition. High-resolution transmission electron microscopy, X-ray diffraction and Rutherford backscattering spectroscopy/ion channeling were used to characterize the microstructure, defect content, composition and epitaxial single-crystal quality of the films. In these films with up to ∼ 34 atomic percent Mg incorporation, an intense ultraviolet band edge photoluminescence at room temperature and 77 K was observed. The highly efficient photoluminescence is indicative of the excitonic nature of the material. Transmission spectroscopy revealed that the excitonic structure of the alloys was clearly visible at room temperature. Post-deposition annealing in oxygen reduced the number of defects and improved the optical properties of the films. The potential applications of MgZnO alloys in a variety of optoelectronic devices are discussed.

Photoluminescence Enhancement of CdS Nanocrystals Fabricated on Dithiocarbamate Functionalized PET Substrates

2012 ◽  
Vol 512-515 ◽  
pp. 1511-1515
Author(s):  
Chun Lin Zhao ◽  
Li Xing ◽  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hexagonal Structure ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Cds Nanocrystals ◽  
Morphological Studies ◽  
Transmission Electron

Cadmium sulfide (CdS) nanocrystals (NCs) were self-assembled and in-situ immobilized on the dithiocarbamate (DTCs)-functionalized polyethylene glycol terephthalate (PET) substrates between the organic (carbon disulfide diffused in n-hexane) –aqueous (ethylenediamine and Cd2+ dissolved in water) interface at room temperature. Powder X-ray diffraction measurement revealed the hexagonal structure of CdS nanocrystals. Morphological studies performed by scanning electron microscopy (SEM) and high-resolution transmission electron microscope (HRTEM) showed the island-like structure of CdS nanocrystals on PET substrates, as well as energy-dispersive X-ray spectroscopy (EDS) confirmed the stoichiometries of CdS nanocrystals. The optical properties of DTCs modified CdS nanocrystals were thoroughly investigated by ultraviolet-visible absorption spectroscopy (UV-vis) and fluorescence spectroscopy. The as-prepared DTCs present intrinsic hydrophobicity and strong affinity for CdS nanocrystals.

scholarly journals Facile Organometallic Synthesis of Fe-Based Nanomaterials by Hot Injection Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1141
Author(s):  
Georgia Basina ◽  
Hafsa Khurshid ◽  
Nikolaos Tzitzios ◽  
George Hadjipanayis ◽  
Vasileios Tzitzios
Keyword(s):  
Room Temperature ◽  
Colloidal Particles ◽  
Iron Pentacarbonyl ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Organometallic Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Hot Injection ◽  
The Stability

Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids’ surface functionalization in a nonpolar solvent.

Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons

2010 ◽  
Vol 97-101 ◽  
pp. 4213-4216
Author(s):  
Jian Xiong Liu ◽  
Zheng Yu Wu ◽  
Guo Wen Meng ◽  
Zhao Lin Zhan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Ceramic Boat

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.

Solute Segregation and Dynamics of Solid-Phase Crystallization In in and Sb-Implanted Silicon

1981 ◽  
Vol 4 ◽  
Author(s):  
J. Narayan ◽  
G. L. Olson ◽  
O. W. Holland
Keyword(s):  
Laser Power ◽  
Solid Phase ◽  
Solute Segregation ◽  
Dislocation Loops ◽  
Solid Phase Crystallization ◽  
Time Resolved ◽  
Plan View ◽  
Ion Channeling ◽  
Retrograde Solubility ◽  
Transmission Electron

ABSTRACTTime-resolved-reflectivity measurements have been combined with transmission electron microscopy (cross-section and plan-view), Rutherford backscattering and ion channeling techniques to study the details of laser induced solid phase epitaxial growth in In+ and Sb+ implanted silicon in the temperature range from 725 to 1500 °K. The details of microstructures including the formation of polycrystals, precipitates, and dislocations have been correlated with the dynamics of crystallization. There were limits to the dopant concentrations which could be incorporated into substitutional lattice sites; these concentrations exceeded retrograde solubility limits by factors up to 70 in the case of the Si-In system. The coarsening of dislocation loops and the formation of a/2<110>, 90° dislocations in the underlying dislocation-loop bands are described as a function of laser power.

Evaluation Humidity Sensing Properties of Graphene/HS-TiO2 Nanocomposites

2021 ◽  
Vol 21 (10) ◽  
pp. 5143-5149
Author(s):  
Zhen Zhu ◽  
Wang-De Lin
Keyword(s):  
Room Temperature ◽  
Response Times ◽  
Sol Gel ◽  
Hollow Spheres ◽  
High Sensitivity ◽  
Humidity Sensing ◽  
X Ray ◽  
Transmission Electron ◽  
Recovery Times ◽  
Relative Humidity Range

This paper reports on a nanocomposite synthesized by sol–gel procedure comprising graphene sheets with hollow spheres of titanium dioxide (G/HS-TiO2) with varying weight percentages of graphene for the purpose of humidity sensors. The surface morphology of the nanocomposite was characterized using transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). The structural properties were examined using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The response to 12–80% RH at room temperature exhibited sensitivity (S = 135). However, the relative humidity range of 12–90% at room temperature exhibited higher sensitivity (S = 557). Sensors fabricated using the proposed nanocomposite exhibited high sensitivity to humidity, high stability, rapid response times, and rapid recovery times with hysteresis error of less than 1.79%. These results demonstrate the outstanding potential of his material for the monitoring of atmospheric humidity. This study also sought to elucidate the mechanisms underlying humidity sensing performance.

Preparation and Properties of Nano-Crystalline Cellulose Electro-Rheological Fluid

2015 ◽  
Vol 815 ◽  
pp. 217-221
Author(s):  
Ling Li Xu ◽  
Xing Ling Shi ◽  
Qing Liang Wang
Keyword(s):  
Room Temperature ◽  
Silicone Oil ◽  
Strong Acid ◽  
Crystalline Cellulose ◽  
Methyl Silicone ◽  
Shearing Stress ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron

nanocrystalline cellulose (NCC) was prepared from micro-crystalline cellulose (MCC) by strong acid hydrolysis. The characteristics of such particle were studied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Electro-rheological fluids (ERF) were prepared by dispersing NCC and MCC in methyl-silicone oil, and their ER effects were measured. Experimental results indicated that NCC ERF exhibited a remarkable ER effect. The highest static shearing stress of NCC ERF (3.5 g/ml) was 5.1 kPa at the room temperature under a 4 .2 kV/mm electric field, increased about 5.5 times compared to MCC ERF, and sedimentation of NCC ERF was not observed even after 60 days.

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