Quantum Confinement of GaAs Nanocrystals Deposited on PMMA Microspheres Using Pulsed Laser Ablation

2013 ◽  
Vol 660 ◽  
pp. 3-9
Author(s):  
Jeong Ho Ryu ◽  
Soon Yong Kweon ◽  
Jung Il Lee ◽  
Sung Lim Ryu

A modified pulsed laser deposition (PLD) was employed to deposit GaAs nanocrystals on the surface of PMMA microspheres. This novel approach is distinguished by the fact that laser ablated materials are deposited uniformly onto the surface of spherical particles that are held constantly in a particle fludization unit. The XRD, SEM, EDX, TEM, EDP and PL results confirmed that cubic structured GaAs nanocrystals were deposited uniformly on the surface of PMMA microspheres with an average diameter of about 15 nm.

2002 ◽  
Vol 17 (3) ◽  
pp. 697-700 ◽  
Author(s):  
D. B. Jan ◽  
Q. X. Jia ◽  
M. E. Hawley ◽  
G. W. Browne ◽  
C. J. Wetteland ◽  
...  

The formation of superconducting YBa2Cu3O7–x (Y123) by in situ pulsed laser deposition from a stoichiometric Y123 target typically requires an oxygen-ambient environment (P ˜ 100–300-mtorr O2) and appropriate substrate temperature during deposition. We have found that pulsed laser deposition from a Y123 target in vacuo onto a (001) LaAlO3 substrate favors the formation of Y2O3. We observed that the Y2O3 (001) films yield three-dimensional nanoscale morphologies that are markedly different from the planar growth surface of conventional superconducting c-axis Y123 films and Y2O3 films formed from the pulsed laser ablation of a Y2O3 target.


2002 ◽  
Vol 752 ◽  
Author(s):  
Zhongsheng Deng ◽  
Thomas J. Pisklak ◽  
Kenneth J. Balkus

ABSTRACTThin films of zeolites including silicalite-1, mordenite and UTD-18 have been prepared on stainless steel foil via pulsed laser deposition (PLD). Laser ablation of as-synthesized zeolite targets onto stainless steel foil followed by a post hydrothermal treatment results in partially oriented zeolite thin films. SEM, XRD were used to characterize the zeolite thin films. Preliminary results for multilayercoatings of different zeolites will also be presented.


RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42088-42093 ◽  
Author(s):  
Deyang Chen ◽  
Shang-Lin Hsu ◽  
Ajay K. Yadav ◽  
James D. Clarkson

A novel approach is proposed to synthesize orientation-controllable single nanocrystal Co3O4 using PLD by the decomposition of BiCoO3.


1999 ◽  
Vol 581 ◽  
Author(s):  
K.M. Hassan ◽  
A.K. Sharma ◽  
J. Narayan ◽  
J.F. Muth ◽  
C.W. Teng ◽  
...  

ABSTRACTWe have fabricated Ge nanostructures buried in AlN and Al2O3 matrices grown on Si(111) and sapphire substrates by pulsed laser deposition. Our approach involved three-dimensional island growth of low band-gap material followed by a layer of wide band-gap material. The nanodots were uniformly distributed in between alternating layers of AlN or Al2O3. It was observed that these nanodots exhibit crystalline structure when grown at 300-500 °C. The average size of Ge islands was determined to be ∼5-15 nm, which could be varied by controlling laser deposition and substrate parameters. The Raman spectrum showed a peak of the Ge-Ge vibrational mode downward shifted upto 295 cm− which is caused by quantum confinement of phonons in the Ge-dots. The photoluminescence of the Ge dots (size ∼15nm) was blue shifted by ∼0.266 eV from the bulk Ge value of 0.73 eV at 77 K, resulting in a distinct peak at ∼1.0 eV. The spectral positions of both E1 and E2 transitions in the absorption spectra at room temperature and 77K shift toward higher energy as the Ge dot size decreases. The interpretation of these behaviors in terms of quantum confinement is discussed in this work, and the importance of pulsed laser deposition in fabricating novel nanostructures is emphasized


2011 ◽  
Vol 415-417 ◽  
pp. 747-750
Author(s):  
Bing Xu ◽  
Ren Guo Song ◽  
Chao Wang

In order to study the effects of laser fluence on silver nanoparticles colloid, the silver nanoparticles colloid was prepared by pulsed laser ablation of silver target for 10min in distilled water at different laser fluence. The particles size,morphologies and absorption spectroscopy of the obtained nanoparticles colloid were characterized by ultraviolet to visible (UV-Vis) spectrometer and transmission electron microscopy (TEM), the average diameter and its distribution were analyzed by Image-ProPlus software. The results shown that the average diameter of the silver nanoparticles prepared at the laser fluence of 4.2J/cm2 was the smallest (D=17.54nm), also, the distribution of particle size was narrowest (=36.86nm) and the morphologies were more homogeneous. It was confirmed that the nanoparticles size and shape could be controlled by pulsed laser ablation parameters.


2002 ◽  
Vol 186 (1-4) ◽  
pp. 282-287 ◽  
Author(s):  
Frédéric Aubriet ◽  
Nouari Chaoui ◽  
Rachel Chety ◽  
Benoı̂t Maunit ◽  
Eric Millon ◽  
...  

2005 ◽  
Vol 12 (04) ◽  
pp. 539-543 ◽  
Author(s):  
QUANHE BAO ◽  
CHUANZHONG CHEN ◽  
LUBIN CHEN ◽  
DIANGANG WANG ◽  
TINGQUAN LEI ◽  
...  

A modified surface layer of hydroxyapatite (HA) target was observed before and after pulsed laser deposition. Two types of HA targets were used for laser ablation. We observed that the surface morphology of the target has a very fine compacted grain structure and presents many irregularities with some microroughness and microporosity before laser ablation. The laser ablated regions can be divided into two areas: one area is porous and rough but the other is dense and smooth. The percentage of particles in the films was high for the films produced with targets that were sintered at 1200°C.


2000 ◽  
Vol 14 (25n27) ◽  
pp. 2713-2718 ◽  
Author(s):  
V. BRACCINI ◽  
D. MARRE' ◽  
A. MOLLICA ◽  
G. GRASSANO ◽  
A. S. SIRI

Superconducting multilayers, whose growth and structure are determined by the kinetic deposition instead by thermodynamics, are a powerful tool for investigating high T c superconductors (HTSC) properties. By means of Pulsed Laser Deposition (PLD), we grew such materials alternating infinite layer phases both pure and doped, to supply CuO 2 planes and charge reservoir (CR) blocks respectively. We found out that using chemically doped CR leads to a semiconducting behavior, whereas oxygen doping seems to be much more effective, since the BaCuO 2 infinite phase, grown in high oxygen partial pressure, does actually bring about a superconducting behavior. We deposited BaCuO 2/ CaCuO 2 superlattices with various periodicities and studied their transport and structural properties. By varying the deposition parameters, we reached both kinetic and thermodynamic growth and we observed semiconducting and superconducting behaviors.


2020 ◽  
Author(s):  
Stefan Andrei Irimiciuc ◽  
Norina Forna ◽  
Andrei Agop ◽  
Maricel Agop ◽  
Stefan Toma ◽  
...  

Understanding the underline fundamental mechanism behind experimental and industrial technologies embodies one of the foundations of the advances and tailoring new materials. With the pulsed laser deposition being one of the key techniques for obtaining complex biocompatible materials with controllable stoichiometry, there is need for experimental and theoretical advancements towards understanding the dynamics of multi component plasmas. Here we investigate the laser ablation process on Cu-Mn-Al and Fe-Mn-Si by means of space-and time-resolved optical emission spectroscopy and fast camera imaging. In a fractal paradigm the space–time homographic transformations were correlated with the global dynamics of the ablation plasmas.


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