GaAs Growth on Micro and Nano Patterned Ge/Si1-XGeX and Si Surfaces

2005 ◽  
Vol 862 ◽  
Author(s):  
Ganesh Vanamu ◽  
Abhaya K. Datye ◽  
Ralph L. Dawson ◽  
Saleem H. Zaidi
Keyword(s):  
Electron Microscopy ◽  
Optical Quality ◽  
Nanometer Scale ◽  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Patterned Structures ◽  
Wet Chemical ◽  
Heteroepitaxial Layers

AbstractWe show heteroepitaxial growth of GaAs on Ge/SiGe grown on nanometer-scale grating structures. Conventional lithography techniques were combined with reactive ion and wet-chemical etching to fabricate 1-D patterns of silicon posts. The quality of the GaAs layers was investigated using high-resolution x-ray diffraction (HRXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence (PL) and etch pit density (EPD) measurements. Our results show significant improvement in the quality of heteroepitaxial layers grown on nano patterned structures compared to those on the unpatterned silicon. The optical quality of the GaAs/Ge/SiGe on nano-scale patterned silicon was comparable to that of single crystal GaAs.

Heteroepitaxial growth and characterization of Ge and SiXGe1−X films on patterned silicon structures

2004 ◽  
Vol 809 ◽  
Author(s):  
Ganesh Vanamu ◽  
Abhaya K. Datye ◽  
Saleem H. Zaidi
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Growth Parameters ◽  
Buffer System ◽  
Heteroepitaxial Growth ◽  
Optimum Configuration ◽  
Transmission Electron ◽  
Silicon Structures ◽  
Heteroepitaxial Layers

ABSTRACTWe describe novel 2-D structures that facilitate strain relief and allow us to obtain Ge epilayers that are free of defects. These structures can potentially absorb thermal expansion and lattice expansion mismatch as well as enable liftoff of heteroepitaxial layers for subsequent wafer reuse. Conventional lithography techniques were combined with reactive ion and wet-chemical etching to fabricate 2-D patterns of silicon posts. The dimensions of the posts were varied keeping the pitch (center to center distance) constant. Heteroepitaxial growth of Ge/SixGe1−x on these micrometer-scale structures was investigated. While, keeping the growth parameters constant, the geometry of the structures was varied to determine the optimum configuration for the highest quality heteroepitaxial growth. The quality of the Si1−xGex buffer system was investigated using high-resolution x-ray diffraction. Transmission electron microscopy (TEM) was used to analyze the epilayer cross-sections. Surface morphology was analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical microscopy. Our results show that the quality of the heteroepitaxial layers improves as the width of the posts in the 2-D pattern was decreased.

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 A comparative study on the VOCs sensing behaviors of various ZnO nanostructures

2020 ◽  
Vol 9 (4) ◽  
pp. 117-122
Author(s):  
Vuong Nguyen Minh ◽  
Dung Dinh Tien ◽  
Hieu Hoang Nhat ◽  
Nghia Nguyen Van ◽  
Truong Nguyen Ngoc Khoa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hierarchical Structure ◽  
Hydrothermal Process ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
Electrospinning Technique ◽  
Transmission Electron ◽  
Volatile Organic ◽  
Wet Chemical

The volatile organic compounds (VOCs) sensing layers were studied using ZnO nanomaterials with different morphologies including hierarchical nanostructure (ZnO-H), nanorods (ZnO-NRs), commercial nanoparticles (ZnO-CNPs) and wet chemical synthesized nanoparticles (ZnO-HNPs). ZnO hierarchical structure was fabricated by an electrospinning technique followed by hydrothermal process. ZnO vertical nanorods structure was fabricated by hydrothermal method, while ZnO nanoparticles based sensors were prepared from commercial powder and wet chemical method. The morphology and properties of the fabricated samples were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). VOCs sensing responses toward acetone, ethanol and methanol with respect to altered ZnO nanostructureswas systematically compared at different working temperatures. The enhanced response at low working temperatures induced by theopen space hierarchical structure was observed. The VOCs sensing mechanisms of the ZnO nanostructures based sensing layer were also explained and discussed in detail. 

Structural and Magnetic study of Al3+ doped Ni0.75Zn0.25Fe2-xAlxO4 nanoferrites

2013 ◽  
Vol 1506 ◽  
Author(s):  
L. Wang ◽  
B. K. Rai ◽  
S. R. Mishra
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Magnetic Dilution ◽  
Wet Chemical ◽  
Structural And Magnetic Properties

AbstractNanostructured Al3+ doped Ni0.75Zn0.25Fe2-xAlxO4 (x = 0.0,0.2,0.4,0.6,0.8, and 1.0) ferrites were synthesized via wet chemical method. X-ray diffraction, transmission electron microscopy, and magnetization measurements have been used to investigate the structural and magnetic properties of spinel ferrites calcined at 950 °C .With the doping of Al3+, the particle size of Ni0.75Zn0.25Fe2-xAlxO4 first increased to 47 nm at x = 0.4 and then decreased down to 37 nm at x = 1. Saturation magnetization decreased linearly with Al3+ due to magnetic dilution. The coercive field showed an inverse dependence on the particle size of ferrites.

Optical properties and energy transfer processes in Tb3+-doped ZnSe quantum dots

2021 ◽  
Author(s):  
Nguyen Ca ◽  
N. D Vinh ◽  
Phan Van Do ◽  
N. T. Hien ◽  
Xuan Hoa Vu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Chemical Method ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transfer Processes ◽  
Transmission Electron ◽  
Wet Chemical

Tb3+-doped ZnSe quantum dots (QDs) with Tb content in the range of 0.5 - 7% were successfully synthesized by a wet chemical method. X-ray diffraction (XRD) and transmission electron microscopy...

Ge Growth on Nanostructured Silicon Surfaces

2005 ◽  
Vol 862 ◽  
Author(s):  
Ganesh Vanamu ◽  
Abhaya K. Datye ◽  
Saleem H. Zaidi
Keyword(s):  
Electron Microscopy ◽  
Dislocation Density ◽  
Full Width Half Maximum ◽  
Defect Density ◽  
Chemical Vapor ◽  
Silicon Surfaces ◽  
X Ray Diffraction ◽  
Etch Pit ◽  
Transmission Electron

AbstractWe report highest quality Ge epilayers on nanoscale patterned Si structures. 100% Ge films of 10 μm are deposited using chemical vapor deposition. The quality of Ge layers was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution x-ray diffraction (HRXRD) measurements. The defect density was evaluated using etch pit density measurements. We have obtained lowest dislocation density (5×105 cm-2) Ge films on the nanopatterned Si structures. The full width half maximum peaks of the reciprocal space maps of Ge epilayers on the nanopatterned Si showed 93 arc sec. We were able to get rid of the crosshatch pattern on the Ge surface grown on the nanopatterned Si. We also showed that there is a significant improvement of the quality of the Ge epilayers in the nanopatterned Si compared to an unpatterned Si. We observed nearly three-order magnitude decrease in the dislocation density in the patterned compared to the unpatterned structures. The Ge epilayer in the patterned Si has a dislocation density of 5×105 cm-2 as compared to 6×108 cm-2 for unpatterned Si.

scholarly journals Sonochemical Synthesis and Properties of YVO4:Eu3+ Nanocrystals for Luminescent Security Ink Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Chinh Dung Trinh ◽  
Phuong Thi Pham Hau ◽  
Thi My Dung Dang ◽  
Chien Mau Dang
Keyword(s):  
Electron Microscopy ◽  
Bulk Material ◽  
Sonochemical Method ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Electrohydrodynamic Printing ◽  
Security Label ◽  
Wet Chemical ◽  
Security Property ◽  
The Eu

Solutions and redispersible powders of nanocrystalline, europium-doped YVO4, are prepared via a wet chemical method using the ultrasonic processor (sonochemical) and microwave and thermal stirring. From X-ray diffraction (XRD) results, YVO4:Eu3+ nanoparticles synthesized using sonochemical method have better crystallinity than those prepared using thermal stirring and microwave methods exhibiting the tetragonal structure known for bulk material. From field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results, it is found that the size of nanoparticles is around 25 nm and increasing after annealing at 900°C. From UV-Vis result, there is a peak at 270 nm corresponding to the absorption of VO43− groups. The photoluminescence (PL) results clearly show the strongest red emission peak at the wavelength around 618 nm. The highest luminescent intensity is obtained for the sample prepared by the sonochemical method at pH = 12 and annealing temperature at 900°C for 4 h. The average lifetimes of the Eu3+ ions in the samples annealed at 300, 600, and 900°C for 1 h at 618 nm emission under 275 nm excitation are 0.36, 0.62, and 0.64 ms, whereas sample annealed at 900°C for 4 h has lifetime of 0.70 ms. The security ink, containing synthesized YVO4:Eu3+ nanoparticles, is dispersed in glycerol and other necessary solvents. The experimental security labels are printed by inkjet using the electrohydrodynamic printing technique. The resulting lines represented to the security labels are analyzed by the 3D microscope equipment and UV 20 W mercury lamp with a wavelength of ∼254 nm. The seamless line of the printed security label has the value of the width at ∼230 μm, thickness at ∼0.68 μm, and distance between two adjacent lines at 800 μm. This result is compatible for producing security labels in small size (millimeter) in order to increase security property.

Chemical Synthesis of Magnetic Fe3O4 Nanoparticles

2005 ◽  
Vol 475-479 ◽  
pp. 2275-2278 ◽  
Author(s):  
Rui Feng Yang ◽  
Yu Zhen Lv ◽  
Yahui Zhang ◽  
Chen Min Liu ◽  
Lin Guo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fe3o4 Nanoparticles ◽  
Solution Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Solution Method ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Surface Modified

Fe3O4 nanoparticles were simply prepared by a wet chemical solution method. In this method, poly (N-vinyl-2-pyrrolidone) (PVP) was used as surface modified reagent to control the shape of the product. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and X-ray diffraction (XRD) were used to characterize the asprepared Fe3O4 nanoparticles. Furthermore, the magnetic properties of the sample were investigated by a VSM (vibrating sample magnetometer) technique.

Characterization and Growth Mechanism of B12As2 Epitaxial Layers Grown on (1-100) 15R-SiC

2008 ◽  
Vol 1069 ◽  
Author(s):  
Hui Chen ◽  
Guan Wang ◽  
Michael Dudley ◽  
Zhou Xu ◽  
James. H. Edgar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Mechanism ◽  
Heteroepitaxial Growth ◽  
High Quality ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Choice

ABSTRACTA systematic study is presented of the heteroepitaxial growth of B12As2 on m-plane 15R-SiC. In contrast to previous studies of B12As2 on other substrates, including (100) Si, (110) Si, (111) Si and (0001) 6H-SiC, single crystalline and untwinned B12As2 was achieved on m-plane 15R-SiC. Observations of IBA on m-plane (1100)15R-SiC by synchrotron white beam x-ray topography (SWBXT) and high resolution transmission electron microscopy (HRTEM) confirm the good quality of the films on the 15R-SiC substrates. The growth mechanism of IBA on m-plane 15R-SiC is discussed. This work demonstrates that m-plane 15R-SiC is potentially a good substrate choice to grow high quality B12As2 epilayers.

scholarly journals Effect of Reaction Temperature on Size and Optical Properties of NiTiO3Nanoparticles

2012 ◽  
Vol 9 (1) ◽  
pp. 282-288 ◽  
Author(s):  
R. Vijayalakshmi ◽  
V. Rajendran
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Uv Spectroscopy ◽  
Particle Size Effect ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Nickel Titanate ◽  
Different Temperatures ◽  
Wet Chemical

Nickel titanate (NiTiO3) nanoparticles were successfully prepared by wet-chemical method, using nickel acetate and titanium(IV) isopropoxide as Ni, Ti sources and citric acid as complexing reagent. The gel was calcined at different temperatures from 500-700 °C. Results of thermogravimetric analysis (TGA) are given. Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM),transmission electron microscopy (TEM), ultraviolet (UV) spectroscopy, vibrating sample magnetometer (VSM) were used to characterize the crystallization process, particle size, morphology, optical and magnetic properties of the calcined nanoparticles. TEM result reveals that the NiTiO3was homogeneous and hexagon morphology with the grain size of 30-70 nm. The band gap values of the NiTiO3nanoparticles were calculated to be 3.43, 3.39 and 3.31 eV. The magnetic property was confirmed that the NiTiO3nanoparticles of super paramagnetic behavior in nature. Our results suggested that the temperature plays an important role in the particle size effect of nanocrystalline NiTiO3.

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