Evolution of photoluminescence from Si nanocrystals embedded in a SiO2 matrix prepared by reactive pulsed laser deposition

2009 ◽  
Vol 24 (7) ◽  
pp. 2259-2267 ◽  
Author(s):  
Fang Fang ◽  
Wei Zhang ◽  
Jian Sun ◽  
Ning Xu ◽  
Jiang Zhu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Pulsed Laser ◽  
Average Diameter ◽  
Peak Position ◽  
Nitrogen Atmosphere ◽  
Film Deposition ◽  
Structural Variations ◽  
Si Nanocrystals ◽  
Before And After

Photoluminescence (PL) properties of SiOx thin films deposited by pulsed laser ablation of Si in a reactive oxygen ambient and annealed in a nitrogen atmosphere were studied at room temperature. Raman spectroscopy, Fourier transform infrared spectroscopy, and optical transmission measurements were used to characterize the deposited films before and after annealing and complement the PL studies. Strong PL due to quantum confinement was observed at room temperature from Si nanocrystals with an average diameter of approximately 5 nm at 325-nm light excitation. An apparent dependence of PL on the oxygen pressure for film deposition was observed. A detailed analysis of the effects of the annealing temperature revealed a significant PL evolution in luminescence intensity, spectrum profile, peak position, and spectrum range with the annealing temperature ranging from 300 to 1200 °C. Structural variations induced by thermal annealing of the films deposited at different oxygen pressures were also discussed on the basis of their correlation with the PL evolution.

Titanium Oxynitride Thin Film Deposition by Pulsed Laser Ablation of Titanium Targets in Nitrogen

1992 ◽  
Vol 285 ◽  
Author(s):  
V. Craciun ◽  
D. Craciun ◽  
S. Amirhaghi ◽  
M. Vickers ◽  
S. Tarling ◽  
...  
Keyword(s):  
Chemical Resistance ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Nitrogen Atmosphere ◽  
Film Deposition ◽  
Laser Deposition ◽  
High Oxygen Content ◽  
Si Substrates ◽  
High Electrical Resistivity

ABSTRACTReactive pulsed laser deposition of titanium targets in a nitrogen atmosphere has been used to deposit thin titanium oxynitride films on Si substrates. The gold coloured layers exhibited a smooth, featureless surface and good chemical resistance in HF-HNO3 mixtures. The films had a high oxygen content which was responsible for relatively high electrical resistivity, measured to be 200–600 μΩ cm. This new method can easily be applied to the growth of other important nitrides such as ZrN, WN, HfN or the deposition of multilayer structures such as TiN/Ti on a variety of substrates.

scholarly journals Влияние бора на структуру и проводимость тонких пленок, получаемых лазерной абляцией алмаза при 700-=SUP=-o-=/SUP=-C

2018 ◽  
Vol 44 (12) ◽  
pp. 16
Author(s):  
Р.И. Романов ◽  
В.Ю. Фоминский ◽  
П.В. Зинин ◽  
И.А. Троян ◽  
Д.В. Фоминский ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Room Temperature ◽  
Diffusion Processes ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Diamond Powder ◽  
Atomic Ratio ◽  
Film Deposition ◽  
Chemical Bonds ◽  
Boron Powder

AbstractStructural features of CB_ x films obtained by pulsed laser ablation of targets made of pressed diamond powder with boron-powder additions at B/C atomic ratio of x = 0.33 have been studied. The films were deposited on heated substrates, so that diffusion processes involving C and B atoms on the surface and in the volume of films were possible. Selected conditions of film deposition ensured their effective doping with boron (0.4 ≤ x ≤ 0.6). The incorporation of B atoms was accompanied by the formation of B–C chemical bonds, whereas the formation of sp ^2 graphite bonds and their ordering in clusters with laminar packing was suppressed. The films possessed very low resistivity (~1.4 mΩ cm) at room temperature and exhibited metallic type of conductance on decreasing the temperature to 77 K.

Effect of Annealing Temperature on Two-Step Method of GaN Films

2012 ◽  
Vol 629 ◽  
pp. 9-13
Author(s):  
Mei Liu ◽  
Xue You Xu ◽  
Bao Yuan Man ◽  
De Min Kong
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Annealing Temperature ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Nitrogen Atmosphere ◽  
Laser Source ◽  
Step Method ◽  
Experimental Conditions ◽  
Force Microscopy

GaN thin films have been deposited on Si (111) substrates by pulsed laser deposition (PLD) of a GaN target in nitrogen atmosphere. An Nd: YAG pulsed laser with a wavelength of 1064 nm was used as a laser source. The results indicate that the GaN thin films deposited only by PLD are amorphous. By annealing in an NH3 atmosphere, the quality of the GaN thin films is improved, and the crystallzinity GaN thin films were obtained. The influence of annealing temperature on the crystallinity, structure, surface morphology and optical properties of GaN films have been examined by X-ray diffraction (XRD), atomic force microscopy (AFM) and infrared spectrum. In our experimental conditions, the GaN thin films deposited by PLD with a laser energy of 250 mJ, growth temperature of 800 °C and annealed at 1000 °C have the best surface morphology and crystalline quality.

New Method for Improving Formability of AZ31B Magnesium Alloy Sheets

2009 ◽  
Vol 610-613 ◽  
pp. 737-741 ◽  
Author(s):  
Guang Sheng Huang ◽  
Wei Xu ◽  
Guang Jie Huang ◽  
Hong Cheng Li ◽  
Fu Sheng Pan
Keyword(s):  
Magnesium Alloy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Orthogonal Experiment ◽  
Alloy Sheet ◽  
New Method ◽  
Technological Parameters ◽  
Magnesium Alloy Sheet ◽  
Before And After ◽  
Cold Rolled

The magnesium alloy sheets have poor plasticity and formability due to their strong (0002) basal texture. In this paper a new method, repeatedly unidirectional bending (RUB), was used to improve formability of the magnesium alloy sheets. The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and reserve surface RUB. The result showed that better formability can be obtained by the reserve surface RUB. Focused on the development of formability of magnesium alloy sheet, the technological parameters, such as RUB passes, radius of support, annealing temperature and holding time, were determined by orthogonal experiment,and hence the optimal RUB process was acquired. Mechanical property of the samples before and after RUB were characterized and compared. After RUB, (0002) basal textural component of cold rolled magnesium alloy sheet was weakened and σb, σ0.2 decreased obviously. The Erichsen values can be considerably enhanced from 3.53mm to around 6.0mm through RUB.The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and

Rapid Synthesis of Cyclomatrix Polyphosphazene Spheres and their Application for the Production of Microporous Carbon Spheres

2011 ◽  
Vol 266 ◽  
pp. 188-191 ◽  
Author(s):  
Jian Wei Fu ◽  
Qun Xu
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Total Pore Volume ◽  
Average Diameter ◽  
Nitrogen Atmosphere ◽  
Bet Surface Area ◽  
Carbon Spheres ◽  
Rapid Synthesis ◽  
N2 Adsorption ◽  
Micropore Size

Uniform cyclomatrix polyphosphazene spheres with diameter of about 410 nm were firstly synthesized rapidly at room temperature by precipitation polymerization of hexachlorocyclotriphosphazene with 4,4′-sulfonyldiphenol, using triethylamine as acid-acceptor and acetonitrile as solvent. Then, monodisperse carbon spheres with abundant micropores were produced by carbonization of the polyphosphazene spheres at a high temperature under a nitrogen atmosphere. As-produced carbon spheres were well characterized by SEM, TEM, EDX, and N2 adsorption technique. Results show that the carbon spheres possess an average diameter of 320 nm, a BET surface area of about 752 m2·g-1, a total pore volume of 0.55 m3·g-1, and a micropore size distribution.

scholarly journals Effect of annealing temperature on structural and optical properties of Cr2O3 thin films by PLD

2018 ◽  
Vol 16 (37) ◽  
pp. 178-189
Author(s):  
Mahdi Hasan Suhail
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Morphological Analysis ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Structural And Optical Properties ◽  
Before And After

In the present work, pulsed laser deposition (PLD) technique was applied to a pellet of Chromium Oxide (99.999% pure) with 2.5 cm diameter and 3 mm thickness at a pressure of 5 Tons using a Hydraulic piston. The films were deposited using Nd: YAG laser λ= (4664) nm at 600 mJ and 400 number of shot on a glass substrate, The thickness of the film was (107 nm). Structural and morphological analysis showed that the films started to crystallize at annealing temperature greater than 400 oC. Absorbance and transmittance spectra were recorded in the wavelength range (300-4400) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant were also study. It was found that all these parameters decrease as the annealing temperature increased to 500 °C, while the energy gap after annealing increase from 3.4 eV to 3.85 eV.

Electron microscopy of pulsed-laser-deposited thin films for tribological applications

1993 ◽  
Vol 51 ◽  
pp. 852-853
Author(s):  
Scott D. Walck ◽  
Jeffrey S. Zabinski ◽  
Michael S. Donley
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Spherical Particles ◽  
Significant Feature ◽  
Great Success ◽  
Deposition Technique ◽  
Coating Materials

Pulsed laser deposition (PLD) is a novel thin film deposition technique which has recently been applied to tribological materials with great success. PLD has several inherent advantages over conventional deposition techniques, including excellent film adhesion, replication of target chemistry, and low film deposition temperature. Because load-bearing materials are typically hardened, heat treated alloys, these properties of PLD are ideally suited for tribological applications. In addition to being a relatively simple deposition technique, considerable processing flexibility is inherent with PLD. Dense, nonporous, stoichiometric films of solid lubricants, such as MoS2, have been grown having long wear lives with low coefficients of friction. Hard coating materials, such as TiC, have been grown at room temperature that were polycrystalline and had excellent wear properties.A significant feature of pulsed laser deposited (PLD) thin films is the incorporation of spherical particles within the films. Figure 1 shows these particles embedded in a film of PLD MoS2 deposited at room temperature.

Magnetron Sputtering High Temperature Mo-Al2O3 Cermet Solar Selective Coatings

2007 ◽  
Vol 546-549 ◽  
pp. 1773-1776 ◽  
Author(s):  
Xin Kang Du ◽  
Cong Wang ◽  
Tian Min Wang ◽  
Bu Liang Chen ◽  
Long Zhou ◽  
...  
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Layer Structure ◽  
Steel Substrate ◽  
Annealing Treatment ◽  
Solar Absorptance ◽  
Selective Coating ◽  
Before And After ◽  
Different Temperatures

Based on double cermet layer structure, Mo-Al2O3 cermet solar selective coating was prepared on stainless steel substrate. A solar absorptance of 0.92 and normal emittance of 0.19 at room temperature have been achieved. Vacuum annealing treatment was done and its influences on the solar selective performance was discussed. Absorptance changed between 0.90 and 0.92 under the selected annealing temperature range of 350-800°C, and emittance varied from 0.19 to 0.23 when heated at 650°C. The microstructures before and after annealing process at different temperatures were investigated.

Ni-Mn-In Heusler Alloy Thin Films Grown by Pulsed Laser Deposition

2012 ◽  
Vol 190 ◽  
pp. 311-314 ◽  
Author(s):  
A. Grunin ◽  
A.Y. Goikhman ◽  
V. Rodionova
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Heusler Alloy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Optimal Annealing Temperature ◽  
Structure Properties

We report on the results of the magnetic and structure properties investigation of Heusler alloy films. Ni-Mn-In thin films were formed by pulsed laser deposition. Stoichiometry was varied and controlled by co-deposition technique. The different deposition conditions and influence of the annealing temperature on the film composition were investigated using Auger electron spectroscopy and Rutherford backscattering spectrometry. The optimal annealing temperature was found to be 620 K. The set of the films deposited on the oxidized Si (100) substrate at room temperature and annealed at 620 K was investigated using X-ray diffractometry at room temperature and Vibrating sample magnetometery at low temperatures. The crystal structure was found to be a mixture of austenitic and martensitic phases at room temperature. Decreasing of Curie temperature from 270 K to 250 K with the decreasing of In concentration from 20 at % to 15 at % was observed.

scholarly journals Study the effect of thermal annealing on some physical properties of thin Cu2SiO3 films prepared by pulsed laser deposition

2018 ◽  
Vol 15 (35) ◽  
pp. 148-157
Author(s):  
Iqbal S. Naji
Keyword(s):  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Average Diameter ◽  
Amorphous Structure ◽  
Laser Deposition ◽  
Si Substrates ◽  
Operation Temperature ◽  
Low Sensitivity ◽  
Binary Compounds

The Cu2SiO3 composite has been prepared from the binary compounds (Cu2O, and SiO2) with high purity by solid state reaction. The Cu2SiO3 thin films were deposited at room temperature on glass and Si substrates with thickness 400 nm by pulsed laser deposition method. X-ray analysis showed that the powder of Cu2SiO3 has a polycrystalline structure with monoclinic phase and preferred orientation along (111) direction at 2θ around 38.670o which related to CuO phase. While as deposited and annealed Cu2SiO3 films have amorphous structure. The morphological study revealed that the grains have granular and elliptical shape, with average diameter of 163.63 nm. The electrical properties which represent Hall effect were investigated. Hall coefficient is negative which means that the films are n-type, and the electrical conductivity decreases with heat treatment.The sensing properties of the Cu2SiO3 sensors for NO2 gas have been studied, and the result revealed that the Cu2SiO3 films have low sensitivity at room temperature, and it's improve with increasing the operation temperature. The response time increase while the recovery time decrease with increasing operation temperature.

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