ZnO Nanosquids: Branching Nanowires from Nanotubes and Nanorods

2008 ◽  
Vol 8 (1) ◽  
pp. 233-236 ◽  
Author(s):  
Samuel L. Mensah ◽  
Abhishek Prasad ◽  
Jiesheng Wang ◽  
Yoke Khin Yap
Keyword(s):  
Building Blocks ◽  
Band Edge Emission ◽  
Edge Emission ◽  
One Dimensional ◽  
Nanoelectronic Devices ◽  
Si Substrates ◽  
Nanophotonic Devices ◽  
Crystal Growth Mechanism ◽  
Sharp Band ◽  
Solid Crystal

One-dimensional (1D) semiconductor nanostructures are promising building blocks for future nano-electronic and nanophotonic devices. ZnO has proven to be a multifunctional and multistructural nanomaterial with promising properties. Here we report the growth of ZnO nanosquids which can be directly grown on planar oxidized Si substrates without using catalysts and templates. The formation of these nanosquids can be explained by the theory of nucleation, and the vapor-solid crystal growth mechanism. The branching nanowires of these ZnO nanosquids could have potential application in multiplexing future nanoelectronic devices. The sharp band-edge emission at ∼380 nm indicates that these ZnO nanosquids are also applicable for interesting optoelectronic devices.

Chemical Vapor Deposition of Porous GaN Particles on Silicon

2012 ◽  
Vol 18 (4) ◽  
pp. 905-911 ◽  
Author(s):  
Joan J. Carvajal ◽  
Oleksandr V. Bilousov ◽  
Dominique Drouin ◽  
Magdalena Aguiló ◽  
Francesc Díaz ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Band Edge ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Si Substrates ◽  
Internal Morphology ◽  
Simple Chemical

AbstractWe present a technique for the direct deposition of nanoporous GaN particles on Si substrates without requiring any post-growth treatment. The internal morphology of the nanoporous GaN particles deposited on Si substrates by using a simple chemical vapor deposition approach was investigated, and straight nanopores with diameters ranging between 50 and 100 nm were observed. Cathodoluminescence characterization revealed a sharp and well-defined near band-edge emission at ∼365 nm. This approach simplifies other methods used for this purpose, such as etching and corrosion techniques that can damage the semiconductor structure and modify its properties.

Characteristics of GaN/Si(111) Epitaxy Grown using Al0.1Ga0.9N/AlN Composite Nucleation Layers having Different Thicknesses of AlN

2002 ◽  
Vol 722 ◽  
Author(s):  
Seong-Hwan Jang ◽  
Seung-Jae Lee ◽  
In-Seok Seo ◽  
Haeng-Keun Ahn ◽  
Oh-Yeon Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Growth Characteristics ◽  
Band Edge ◽  
Band Edge Emission ◽  
Yellow Luminescence ◽  
Edge Emission ◽  
Etch Pits ◽  
Nucleation Layer ◽  
Sharp Band ◽  
Surface Morphologies

AbstractWe have studied the effects of Al0.1Ga0.9N(150 nm)/AlN Composite Nucleation Layers (CNLs) having different thicknesses of AlN ranging from 20 to 41 nm on the growth characteristics of GaN/Si(111) epitaxy. The surface morphologies of the GaN epitaxial layers which were grown on Al0.1Ga0.9N(150nm)/AlN CNLs showed that the number of thermal etch pits and cracks was abruptly decreased with the increase of AlN thickness from 20 to 35 nm. However, the morphology of GaN epitaxy which was grown on Al0.1Ga0.9N(150 nm)/AlN CNL having AlN of 41 nm thick above 35 nm showed that the number of them was increased again. So, the GaN/Si(111) epitaxy which was grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL showed the highest crystallinity having the FWHM of 1157 arcsec for the (0002) diffraction. Photoluminescence spectrum at room temperature for GaN/Si(111) epitaxy grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL showed a sharp band edge emission at 364 nm, which especially doesn't have yellow luminescence related to various defects such as vacancy and dislocation. Meanwhile, the spectra at room temperature for the others showed yellow luminescence at around 580 nm except each band edge emission. Moreover, the FWHM of main exitonic peak at 10 K for the GaN/Si(111) epitaxy which was grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL is the lowest value of 12.81 meV among them. It is obvious that the Al0.1Ga0.9N(150 nm)/AlN CNL having suitable thickness of AlN plays an important role in improving the crystallinity and optical properties of GaN/Si(111) heteroepitaxy without any defects such as pits and cracks over the surface by reducing the mismatch of thermal expansion coefficient and lattice constant between GaN and Si(111) comparing with AlxGa1-xN or AlN nucleation layer alone.

scholarly journals Nanocrystalline Oxides: CdS nanowires synthesized by solvothermal method

2014 ◽  
Vol 70 (a1) ◽  
pp. C1414-C1414
Author(s):  
Nomery Hadia ◽  
Santiago Garcia-Granda ◽  
Jose Garcia
Keyword(s):  
Metal Oxide ◽  
Single Crystal ◽  
Research Programme ◽  
Building Blocks ◽  
Mediterranean Area ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
One Dimensional ◽  
Wide Range ◽  
Cds Nanowires

Recent advances in the field of nanotechnology produced an assortment of one-dimensional (1D) structures, such as nanowires and nanorods. These fascinating materials are the potential building blocks for a wide range of nanoscale electronics, optoelectronics, magnetoelectronics, or sensing devices [1]. Parallel to the success with group IV and groups III–V compounds semiconductor nanostructures, semiconducting metal oxide materials with wide band gaps are attracting attention [2-3]. The main aim of this communication is to report our results on the application of several new techniques, particularly the use of hydrothermal synthesis, to fabricate single crystal one-dimensional nanostructured materials, study their growth processes, understand the growth mechanisms and investigate their physical properties. A wide range of remarkable features are then presented, to cover a number of metal oxides, such as ZnO, Sb2O3, CdS, MgO, α-Fe2O3, or TiO2, describing their structures, optical, magnetic, mechanical and chemical sensing properties. These studies constitute the basis for developing versatile applications based on metal oxide 1D systems as well as highlighting the current progress in device development. To exemplify, the as-prepared CdS nanowires have average 28 nm in diameter and length up to several micrometres. The direct band gap of the CdS nanowires is 2.56 eV calculated by the UV-vis absorption spectra. The PL spectrum has two distinct emission bands at 502 nm and 695 nm, which are associated with the near-band-edge emission and defect emission, respectively. These synthesized single-crystal CdS nanowires have a high potential in the optoelectronic applications of nanolasers, solar cells, lighting-emitting diodes or photodetectors. Acknowledgments: Erasmus Mundus MEDASTAR (Mediterranean Area for Science, Technology and Research) Programme, 2011–4051/002–001-EMA2, Spanish MINECO (MAT2010-15094, Factoría de Cristalización – Consolider Ingenio 2010) and ERDF.

Enhancement of the core near-band-edge emission induced by an amorphous shell in coaxial one-dimensional nanostructure: the case of SiC/SiO2core/shell self-organized nanowires

2010 ◽  
Vol 21 (34) ◽  
pp. 345702 ◽  
Author(s):  
Filippo Fabbri ◽  
Francesca Rossi ◽  
Giovanni Attolini ◽  
Giancarlo Salviati ◽  
Salvatore Iannotta ◽  
...  
Keyword(s):  
Band Edge ◽  
Near Band Edge Emission ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Edge Emission ◽  
One Dimensional ◽  
The Core ◽  
Self Organized

Differences in Morphologies of GaN-Based Nanocrystals Grown on Metal-Foils and Multi-Crystalline Si Substrates

2018 ◽  
Vol 941 ◽  
pp. 2109-2114
Author(s):  
Yuichi Sato ◽  
Atomu Fujiwara ◽  
Nguyen Duc Trung ◽  
Sora Saito
Keyword(s):  
Growth Temperature ◽  
Crystalline Silicon ◽  
The Other ◽  
Band Edge Emission ◽  
Metal Foil ◽  
Cathodoluminescence Spectrum ◽  
Si Substrate ◽  
Edge Emission ◽  
Si Substrates ◽  
Metal Foils

Gallium nitride (GaN)-based thin films consist of its nanocrystals are grown on some metal-foils and a multi-crystalline silicon (Si) substrates. Their morphologies are compared with each other and the differences are discussed. Pillar-shaped nanocrystals are observed in the film grown on the multi-crystalline Si substrate while such structures are not observed in the films grown on the metal-foils when they are grown at higher growth temperatures. On the other hand, the morphologies of the films grown on the metal-foils approach to pillar-like structures by reducing the growth temperature. Band-edge emission is clearly observed in a cathodoluminescence spectrum of the film grown on the metal-foil at the reduced growth temperature.

scholarly journals Synthesis and Characterization of One-Dimensional Porous (Zn,Cd)S/SiO2Composite Nanostructural Materials

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xiuli Fu ◽  
Guijun Ban ◽  
Dan Li ◽  
Hanyuan Chen ◽  
Zhijian Peng
Keyword(s):  
Oxygen Vacancies ◽  
Thermal Evaporation ◽  
Gaussian Function ◽  
Band Edge Emission ◽  
Photoluminescence Spectra ◽  
Porous Composite ◽  
Edge Emission ◽  
One Dimensional ◽  
Different Temperatures

One-dimensional (1D) porous (Zn,Cd)S/SiO2composite nanostructural materials were synthesized by thermal evaporation of ZnS and CdS mixture powder at 950°C. The nanomaterials were collected from silicon wafers which were coated with 10 nm thick gold and were set apart from the source about 10 cm away. The diameter of the as-prepared 1D porous composite nanostructures is in the range of 1–1.5 μm and their lengths are up to tens to hundreds of micrometers. The photoluminescence spectra measured at different temperatures of the prepared nanostructures display a similar broadband signature, which can be fitted by Gaussian function into three emission peaks centered at 477, 536, and 588 nm and attributed to band edge emission, neutral oxygen vacancies, and antisymmetric stretching of Si–O–Si and nonstoichiometric SiOx(1<x<2), respectively.

Enhancement of band-edge emission of ZnO from one-dimensional ZnO/MgZnO core/shell nanostructures

2009 ◽  
Vol 42 (11) ◽  
pp. 115106 ◽  
Author(s):  
Cheol Hyoun Ahn ◽  
Sanjay Kumar Mohanta ◽  
Bo Hyun Kong ◽  
Hyung Koun Cho
Keyword(s):  
Band Edge ◽  
Core Shell ◽  
Band Edge Emission ◽  
Edge Emission ◽  
One Dimensional ◽  
Shell Nanostructures

Pendeo-Epitaxial Growth of GaN on SiC and Silicon Substrates via Metalorganic Chemical Vapor Deposition

1999 ◽  
Vol 572 ◽  
Author(s):  
K. J. Linthicum ◽  
T. Gehrke ◽  
D. Thomson ◽  
C. Ronning ◽  
E. P. Carlson ◽  
...  
Keyword(s):  
Chemical Vapor ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Silicon Substrates ◽  
Lateral Growth ◽  
X Ray Diffraction ◽  
Edge Emission ◽  
X Ray ◽  
Si Substrates ◽  
Crystallographic Tilt

ABSTRACTPendeo-epitaxial lateral growth (PE) of GaN epilayers on (0001) 6H-silicon carbide and (011) Si substrates has been achieved. Growth on the latter substrate was accomplished through the use of a 3C-SiC transition layer. The coalesced PE GaN epilayers were characterized using scanning electron diffraction, x-ray diffraction and photoluminescence spectroscopy. The regions of lateral growth exhibited ∼0.2° crystallographic tilt relative to the seed layer. The GaN seed and PE epilayers grown on the 3C-SiC/Si substrates exhibited comparable optical characteristics to the GaN seed and PE grown on 6H-SiC substrates. The near band-edge emission of the GaN/3C-SiC/Si seed was 3.450 eV (FWHM ∼ 19 meV) and the GaN/6H-SiC seed was 3.466 eV (FWHM ∼ 4 meV).

scholarly journals Novel Bloch wave excitation platform based on few-layer photonic crystal deposited on D-shaped optical fiber

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Gonzalez-Valencia ◽  
Ignacio Del Villar ◽  
Pedro Torres
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Light Propagation ◽  
Fiber Optic ◽  
Layer Structure ◽  
Optical Network ◽  
Building Blocks ◽  
Bloch Wave ◽  
Nanophotonic Devices ◽  
Wide Range

AbstractWith the goal of ultimate control over the light propagation, photonic crystals currently represent the primary building blocks for novel nanophotonic devices. Bloch surface waves (BSWs) in periodic dielectric multilayer structures with a surface defect is a well-known phenomenon, which implies new opportunities for controlling the light propagation and has many applications in the physical and biological science. However, most of the reported structures based on BSWs require depositing a large number of alternating layers or exploiting a large refractive index (RI) contrast between the materials constituting the multilayer structure, thereby increasing the complexity and costs of manufacturing. The combination of fiber–optic-based platforms with nanotechnology is opening the opportunity for the development of high-performance photonic devices that enhance the light-matter interaction in a strong way compared to other optical platforms. Here, we report a BSW-supporting platform that uses geometrically modified commercial optical fibers such as D-shaped optical fibers, where a few-layer structure is deposited on its flat surface using metal oxides with a moderate difference in RI. In this novel fiber optic platform, BSWs are excited through the evanescent field of the core-guided fundamental mode, which indicates that the structure proposed here can be used as a sensing probe, along with other intrinsic properties of fiber optic sensors, as lightness, multiplexing capacity and easiness of integration in an optical network. As a demonstration, fiber optic BSW excitation is shown to be suitable for measuring RI variations. The designed structure is easy to manufacture and could be adapted to a wide range of applications in the fields of telecommunications, environment, health, and material characterization.

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