scholarly journals Two-path phonon interference resonance induces a stop band in a silicon crystal matrix with a multilayer array of embedded nanoparticles

2020 ◽  
Vol 102 (2) ◽  
Author(s):  
Shiqian Hu ◽  
Lei Feng ◽  
Cheng Shao ◽  
Ivan A. Strelnikov ◽  
Yuriy A. Kosevich ◽  
...  
Keyword(s):  
Silicon Crystal ◽  
Stop Band ◽  
Crystal Matrix ◽  
Embedded Nanoparticles

Otoconia perfect/imperfect crystals

1994 ◽  
Vol 52 ◽  
pp. 42-43
Author(s):  
César D. Fermin ◽  
Dale Martin
Keyword(s):  
Image Processing ◽  
Room Temperature ◽  
Phosphotungstic Acid ◽  
Gallus Domesticus ◽  
Crystal Matrix ◽  
Organic Templates ◽  
Image Processing Algorithms ◽  
Processing Algorithms ◽  
Diffraction Patterns

Otoconia of higher vertebrates are interesting biological crystals that display the diffraction patterns of perfect crystals (e.g., calcite for birds and mammal) when intact, but fail to produce a regular crystallographic pattern when fixed. Image processing of the fixed crystal matrix, which resembles the organic templates of teeth and bone, failed to clarify a paradox of biomineralization described by Mann. Recently, we suggested that inner ear otoconia crystals contain growth plates that run in different directions, and that the arrangement of the plates may contribute to the turning angles seen at the hexagonal faces of the crystals.Using image processing algorithms described earlier, and Fourier Transform function (2FFT) of BioScan Optimas®, we evaluated the patterns in the packing of the otoconia fibrils of newly hatched chicks (Gallus domesticus) inner ears. Animals were fixed in situ by perfusion of 1% phosphotungstic acid (PTA) at room temperature through the left ventricle, after intraperitoneal Nembutal (35mg/Kg) deep anesthesia. Negatives were made with a Hitachi H-7100 TEM at 50K-400K magnifications. The negatives were then placed on a light box, where images were filtered and transferred to a 35 mm camera as described.

Morphology and development of flow-pattern defect with extended nonagitated Secco etching

1994 ◽  
Vol 52 ◽  
pp. 868-869
Author(s):  
Y. Pan
Keyword(s):  
Flow Pattern ◽  
Silicon Crystal ◽  
Gate Oxide ◽  
Crystal Growth Rate ◽  
Etch Depth ◽  
Force Microscopy ◽  
Etch Pit ◽  
Float Zone ◽  
Atomic Force ◽  
Multiple Step

The D defect, which causes the degradation of gate oxide integrities (GOI), can be revealed by Secco etching as flow pattern defect (FPD) in both float zone (FZ) and Czochralski (Cz) silicon crystal or as crystal originated particles (COP) by a multiple-step SC-1 cleaning process. By decreasing the crystal growth rate or high temperature annealing, the FPD density can be reduced, while the D defectsize increased. During the etching, the FPD surface density and etch pit size (FPD #1) increased withthe etch depth, while the wedge shaped contours do not change their positions and curvatures (FIG.l).In this paper, with atomic force microscopy (AFM), a simple model for FPD morphology by non-crystallographic preferential etching, such as Secco etching, was established.One sample wafer (FPD #2) was Secco etched with surface removed by 4 μm (FIG.2). The cross section view shows the FPD has a circular saucer pit and the wedge contours are actually the side surfaces of a terrace structure with very small slopes. Note that the scale in z direction is purposely enhanced in the AFM images. The pit dimensions are listed in TABLE 1.

Silicon crystal cooked to perfection

Nature ◽  
2007 ◽  
Author(s):  
Nicola Jones
Keyword(s):  
Silicon Crystal

Modelling of phase boundaries and melt flow in crucible-free silicon crystal growth using high-frequency heating

2017 ◽  
Vol 53 (4) ◽  
pp. 715-722
Author(s):  
K. Suvorovs ◽  
M. Plāte ◽  
J. Virbulis
Keyword(s):  
Crystal Growth ◽  
High Frequency ◽  
Silicon Crystal ◽  
Melt Flow ◽  
Phase Boundaries ◽  
Free Silicon ◽  
Frequency Heating

scholarly journals Control of Oxygen Impurities in a Continuous-Feeding Czochralski-Silicon Crystal Growth by the Double-Crucible Method

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 264
Author(s):  
Wenhan Zhao ◽  
Jiancheng Li ◽  
Lijun Liu
Keyword(s):  
Oxygen Concentration ◽  
Silicon Crystal ◽  
Cost Effective ◽  
Czochralski Method ◽  
Crucible Wall ◽  
Oxygen Impurity ◽  
Continuous Feeding ◽  
The Impact ◽  
Oxygen Impurities ◽  
Crystal Interface

The continuous-feeding Czochralski method is a cost-effective method to grow single silicon crystals. An inner crucible is used to prevent the un-melted silicon feedstock from transferring to the melt-crystal interface in this method. A series of global simulations were carried out to investigate the impact of the inner crucible on the oxygen impurity distributions at the melt-crystal interface. The results indicate that, the inner crucible plays a more important role in affecting the O concentration at the melt-crystal interface than the outer crucible. It can prevent the oxygen impurities from being transported from the outer crucible wall effectively. Meanwhile, it also introduces as a new source of oxygen impurity in the melt, likely resulting in a high oxygen concentration zone under the melt-crystal interface. We proposed to enlarge the inner crucible diameter so that the oxygen concentration at the melt-crystal interface can be controlled at low levels.

Angle and polarization-independent miniaturized UWB FSS design

2021 ◽  
pp. 1-9
Author(s):  
Yanning Yuan ◽  
Yuchen Zhao ◽  
Xiaoli Xi
Keyword(s):  
Design Method ◽  
Incident Angle ◽  
Stop Band ◽  
Single Layer ◽  
Wireless Systems ◽  
Frequency Selective Surface ◽  
Ultra Wideband ◽  
Band Frequency ◽  
Gain Enhancement ◽  
Polarization Independent

Abstract A single-layer ultra-wideband (UWB) stop-band frequency selective surface (FSS) has several advantages in wireless systems, including a simple design, low debugging complexity, and an appropriate thickness. This study proposes a miniaturized UWB stop-band FSS design. The proposed FSS structure consists of a square-loop and metalized vias that are arranged on a single layer substrate; it has an excellent angle and polarization-independent characteristics. At an incident angle of 60°, the polarization response frequencies of the transverse electric and magnetic modes only shifted by 0.003 f0 and 0.007 f0, respectively. The equivalent circuit models of the square-loop and metallized vias structure are analysed and the accuracy of the calculation is evaluated by comparing the electromagnetic simulation. The 20 × 20 array constitutes an FSS reflector with a unit size of 4.2 mm × 4.2 mm (less than one-twentieth of the wavelength of 3 GHz), which realizes an UWB quasi-constant gain enhancement (in-band flatness is <0.5 dB). Finally, the simulation results were verified through sample processing and measurement; consistent results were obtained. The FSS miniaturization design method proposed in this study could be applied to the design of passband FSS (complementary structure), antennas and filters, among other applications.

scholarly journals From Macro to Mesoporous ZnO Inverse Opals: Synthesis, Characterization and Tracer Diffusion Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 196
Author(s):  
Shravan Kousik ◽  
Diane Sipp ◽  
Karina Abitaev ◽  
Yawen Li ◽  
Thomas Sottmann ◽  
...  
Keyword(s):  
Open Porosity ◽  
Laser Scanning ◽  
High Surface ◽  
Stop Band ◽  
Correlation Spectroscopy ◽  
Laser Scanning Microscopy ◽  
Added Value ◽  
Confocal Laser ◽  
Inverse Opals ◽  
Mesoporous Zno

Oxide inverse opals (IOs) with their high surface area and open porosity are promising candidates for catalyst support applications. Supports with confined mesoporous domains are of added value to heterogeneous catalysis. However, the fabrication of IOs with mesoporous or sub-macroporous voids (<100 nm) continues to be a challenge, and the diffusion of tracers in quasi-mesoporous IOs is yet to be adequately studied. In order to address these two problems, we synthesized ZnO IOs films with tunable pore sizes using chemical bath deposition and template-based approach. By decreasing the size of polystyrene (PS) template particles towards the mesoporous range, ZnO IOs with 50 nm-sized pores and open porosity were synthesized. The effect of the template-removal method on the pore geometry (spherical vs. gyroidal) was studied. The infiltration depth in the template was determined, and the factors influencing infiltration were assessed. The crystallinity and photonic stop-band of the IOs were studied using X-Ray diffraction and UV-Vis, respectively. The infiltration of tracer molecules (Alexa Fluor 488) in multilayered quasi-mesoporous ZnO IOs was confirmed via confocal laser scanning microscopy, while fluorescence correlation spectroscopy analysis revealed two distinct diffusion times in IOs assigned to diffusion through the pores (fast) and adsorption on the pore walls (slow).

scholarly journals Dynamic observation of dislocation evolution and interaction with twin boundaries in silicon crystal growth using in – situ synchrotron X-ray diffraction imaging

2021 ◽  
Vol 210 ◽  
pp. 116819
Author(s):  
M.G. Tsoutsouva ◽  
G. Regula ◽  
B. Ryningen ◽  
P.E. Vullum ◽  
N. Mangelinck-Noël ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Silicon Crystal ◽  
X Ray Diffraction ◽  
Twin Boundaries ◽  
X Ray ◽  
Dynamic Observation ◽  
Diffraction Imaging

An FSS Based Stop Band Filter for EM Shielding Application

2020 ◽  
Author(s):  
Tania Tamoor ◽  
Fahad Ahmed ◽  
Syed Muhammad Qasim Ali Shah ◽  
Tayyab Hassan ◽  
Nosherwan Shoaib
Keyword(s):  
Stop Band ◽  
Band Filter
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