Recrystallisation of Cadmium Sulphide Powder Films with a CO2 Laser

1986 ◽  
Vol 74 ◽  
Author(s):  
P. E. Barden ◽  
T. J. Cumberbatch
Keyword(s):  
Thin Films ◽  
Co2 Laser ◽  
Hexagonal Phase ◽  
Cadmium Sulphide ◽  
Average Diameter ◽  
Cubic Phase ◽  
Cathodoluminescence Spectrum ◽  
Polycrystalline Structure ◽  
Narrow Peak ◽  
Close Packed Layer

AbstractThin films (1–2μm) of cadmium sulphide, deposited by electrophoresis, consist of a close packed layer of randomly oriented cubic-phase microcrystalline particles with an average diameter of 30nm. A CW CO2 laser, operating at 10.6μm has been used to convert this into a polycrystalline structure with columnar crystals, of hexagonal phase, which extend through the thickness of the film and whose c-axis is perpendicular to the substrate. The recrystallised regions comprise aligned grains up to 300nm in diameter whose cathodoluminescence spectrum exhibits a narrow peak centred at 2.42eV with a half width identical to that for evaporated CdS (0.1eV).

The Synthesis and Characterization of Novel Cadmium Sulphide Nanocrystallites and their Thin Films

2014 ◽  
Vol 875-877 ◽  
pp. 228-231
Author(s):  
Shafique Ahmed Arain ◽  
Christopher Wilkins ◽  
Hafiz Badaruddin
Keyword(s):  
Thin Films ◽  
Vapour Deposition ◽  
Hexagonal Phase ◽  
Chemical Vapour ◽  
Cadmium Sulphide ◽  
Spherical Shape ◽  
Sem Analysis ◽  
Diethyl Dithiocarbamate ◽  
Lower Temperature

Diethyl dithiocarbamate [Cd (S2CN Et2)2] complex is used to deposit the cadmium sulphide thin film at much lower temperature by Aerosol Assisted Chemical Vapour deposition (AACVD) and same precursor is used to synthesize the nanocrystals in Oleylamine at elevated temperature. Thermogravimetric analysis shows that precursor [Cd (S2CN Et2)2] decomposes in the single stage, losing 62% of total weight. Deposition of thin films at 300°C and 400°C showed the growth of CdS clusters which were made of granular crystallites. These results are confirmed by SEM analysis. Thermolysis of the precursor in oleylamine at 240°C gave the nanoparticles most of them are monodispersed spherical shape, few having mono and dipod structures. TEM images confirm the structures. XRD results show the thin films and nanoparticles have hexagonal phase of CdS.

scholarly journals Annealing Effects on the Properties of Chemically Deposited CdS Thin Films at Ambient Condition

2012 ◽  
Vol 60 (2) ◽  
pp. 283-288 ◽  
Author(s):  
G. Mustafa ◽  
M.R.I. Chowdhury ◽  
D.K. Saha ◽  
S. Hussain ◽  
O. Islam
Keyword(s):  
Thin Films ◽  
Hexagonal Phase ◽  
Ambient Condition ◽  
Cubic Phase ◽  
Optical And Electrical Properties ◽  
Grain Sizes ◽  
Increase With Increase ◽  
Annealing Effects ◽  
Cds Thin Films ◽  
Absorption Measurements

Chemically-deposited CdS thin films have been investigated using various techniques to discuss annealing effects on the structural, morphological, optical and electrical properties of the films. It has been observed from XRD that the deposited layers are mainly consisting of CdS phase. After annealing, metastable cubic phase was transformed into stable hexagonal phase. The average grain sizes were found to increase and the lattice constant, micro-strain and dislocation density were found to decrease after annealing. Optical absorption measurements show that band gap is observed to be 2.42 eV for as deposited and be 2.27 eV upon heat treatment at 673 K for one hour in air. The conductivity of this film has been determined by I-V measurement and observed to increase with increase of temperature. The activation energy of electrical conductivity of this film is also determined.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11536 Dhaka Univ. J. Sci. 60(2): 283-288, 2012 (July)

scholarly journals Effect of laser fluence on structural transformations and photoluminescence quenching of Zinc Selenide nanoparticles thin films

2019 ◽  
Vol 29 (4) ◽  
pp. 122
Author(s):  
Nadheer Jassim Mohammed
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Laser Fluence ◽  
Hexagonal Phase ◽  
Blue Shift ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Znse Nanoparticles ◽  
X Ray ◽  
Pl Spectra

Abstract We reported in this work the growth of ZnSe nanoparticles thin films deposited on glass substrates were synthesized by a pulsed laser deposition (PLD) method. The as obtained films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-VIS Spectrophotometer, and Photoluminescence (PL) spectra. X-ray diffraction study confirmed the transformation the cubic phase of ZnSe nanoparticles into hexagonal phase by increase the laser fluence from (4.77-5.97) J/cm2. The particle size variations were achieved by varying the laser fluence of prepared films. XRD studies and TEM images confirmed the nanometer size was found to lie in the range of 12-80 nm. A UV-VIS study was carried out to measure the band gap of the ZnSe nanoparicles thin films and it showed a blue shift with respect to the bulk value. The PL spectra at room temperature (300K) of the films showed the decrease of maximum values at at 522 nm( 2.379), 521 nm (2.3838) and 520 nm (2.3882 eV) for the laser fluence (4.77, 5.57 and 5.97 J/cm2), respectively. We assigned the variation due a larger number of non-radiative recombination centers appears in the films.

scholarly journals Crystal Growth of Cubic and Hexagonal GaN Bulk Alloys and Their Thermal-Vacuum-Evaporated Nano-Thin Films

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1240
Author(s):  
Marwa Fathy ◽  
Sara Gad ◽  
Badawi Anis ◽  
Abd El-Hady B. Kashyout
Keyword(s):  
Thin Films ◽  
Crystal Growth ◽  
Light Emitting Diode ◽  
Hexagonal Phase ◽  
Average Diameter ◽  
High Electron ◽  
Thermal Vacuum ◽  
Light Emitting ◽  
Cubic Structure ◽  
Bulk Alloys

In this study, we investigate a novel simple methodology to synthesize gallium nitride nanoparticles (GaN) that could be used as an active layer in light-emitting diode (LED) devices by combining the crystal growth technique with thermal vacuum evaporation. The characterizations of structural and optical properties are carried out with different techniques to investigate the main featured properties of GaN bulk alloys and their thin films. Field emission scanning electron microscopy (FESEM) delivered images in bulk structures that show micro rods with an average diameter of 0.98 µm, while their thin films show regular microspheres with diameter ranging from 0.13 µm to 0.22 µm. X-ray diffraction (XRD) of the bulk crystals reveals a combination of 20% hexagonal and 80% cubic structure, and in thin films, it shows the orientation of the hexagonal phase. For HRTEM, these microspheres are composed of nanoparticles of GaN with diameter of 8–10 nm. For the optical behavior, a band gap of about from 2.33 to 3.1 eV is observed in both cases as alloy and thin film, respectively. This article highlights the fabrication of the major cubic structure of GaN bulk alloy with its thin films of high electron lifetime.

REACTIVELY RADIO FREQUENCY SPUTTERED SILVER OXIDE THIN FILMS: PHASE EVOLUTION AND PHASE STABILITY

2007 ◽  
Vol 21 (28) ◽  
pp. 1933-1944 ◽  
Author(s):  
M. N. V. RAMESH ◽  
Y. SUNDARAYYA ◽  
C. S. SUNANDANA
Keyword(s):  
Thin Films ◽  
Radio Frequency ◽  
Silver Oxide ◽  
Hexagonal Phase ◽  
Oxide Phase ◽  
Phase Evolution ◽  
Bandgap Energy ◽  
Cubic Phase ◽  
Oxide Thin Films ◽  
Mixed Gas

The main aim of this paper is to fabricate and characterize silver oxide thin films and to investigate the effect of processing parameters on the microstructure of deposited films. Radio frequency (RF) magnetron sputtering was used under oxygen-argon mixed gas atmosphere for fabrication. Oxide phase evolution and stability were investigated by X-ray diffraction (XRD) of as-deposited and post deposition annealed films. In all cases, the hexagonal phase was initially observed which then got transformed to the cubic phase upon annealing films. The hexagonal–cubic "transition" temperature decreases initially upon increase of oxygen content, which is corroborated by optical spectra. The evolution of optical absorption edge was monitored by a spectrophotometer. A bandgap energy of 3.5 eV was deduced for Ag 2 O at 300 K. Atomic force microscopy (AFM) has revealed the influence of deposition conditions on the surface morphology of the films.

Effect of Gamma Radiation on Structural, Optical and Electrical Properties of nanostructured CdHgTe Thin Films

2018 ◽  
Vol 1 (1) ◽  
pp. 26-31 ◽  
Author(s):  
B Babu ◽  
K Mohanraj ◽  
S Chandrasekar ◽  
N Senthil Kumar ◽  
B Mohanbabu
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Electrical Properties ◽  
Gamma Radiation ◽  
Glass Substrate ◽  
Gamma Ray ◽  
Optical And Electrical Properties ◽  
Deposition Technique ◽  
Polycrystalline Structure ◽  
Dc Electrical Conductivity

CdHgTe thin films were grown onto glass substrate via the Chemical bath deposition technique. XRD results indicate that a CdHgTe formed with a cubic polycrystalline structure. The crystallinity of CdHgTe thin films is gradually deteriorate with increasing the gamma irradiation. EDS spectrums confirms the presence of Cd, Hg and Te elements. DC electrical conductivity results depicted the conductivity of CdHgTe increase with increasing a gamma ray dosage

Transmission Electron Microscope Investigation of Sputtered Co-Pt Thin Films

1985 ◽  
Vol 48 ◽  
Author(s):  
P. Alexopoulos ◽  
R. H. Geiss ◽  
M. Schlenker
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Hexagonal Phase ◽  
Substantial Reduction ◽  
Magnetic Domain ◽  
Dark Field ◽  
Carbon Substrate ◽  
Dark Field Imaging ◽  
Carbon Substrates ◽  
Carbon Coated

ABSTRACTThin films of Co-10 at% Pt, ranging from 15 to 90 nm in thickness, have been DC-sputtered at various temperatures on to carbon-coated mica, carbon substrates on copper grids, or (001) silicon single crystals under 3 μm pressure of Ar, using targets of the alloy in the hexagonal phase, at growth rates of 9 nm/min. The samples were investigated by TEM, using bright-and dark-field imaging, lattice imaging, selected area diffraction and both Fresnel and focussed Lorentz modes. The primary structure of the films was found to be hexagonal, with a = 0.255 nm and c = 0.414 nm. For the samples sputtered at room temperature, the grain sizes were on the order of 0.μm on carbon-coated mica and carbon-substrate grids, and approximately an order of magnitude smaller on silicon substrates. Heavy streaking along the [001] of the hexagonal matrix was observed on diffraction patterns for grains having the [001] parallel to the surface; this streaking was found to be associated with the presence of a high density of faults parallel to the (001). In films sputtered on to carbon-coated mica at 225 °C, where a substantial reduction of the coercivity is observed, the overwhelming majority of the grains had the (001) basal plane parallel to the surface. Lorentz microscopy showed the magnetic domain structure in films grown on silicon to be markedly different from those grown on the carbon substrates, and further changes occurred for the films grown at elevated temperatures.

Rapid Thermal Transformation of A-15 Crystal Structure Metallic Thin Films

1995 ◽  
Vol 387 ◽  
Author(s):  
M. J. O'Keefe ◽  
C. L. Cerny
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Physical Vapor Deposition ◽  
Thermal Transformation ◽  
The Body ◽  
Cubic Phase ◽  
Body Centered Cubic ◽  
Body Center Cubic

AbstractPhysical vapor deposition of Group VI elements (Cr, Mo, W) can lead to the formation of a metastable A-15 crystal structure under certain processing conditions. Typically, a thermally induced transformation of the metastable A-15 structure into the equilibrium body centered cubic structure has been accomplished by conventional furnace annealing at T/Tm ≈ 0.3 from tens of minutes to several hours. In this study we report on the use of rapid thermal annealing to transform sputter deposited A- 15 crystal structure tungsten and chromium thin films into body centered cubic films within the same temperature range but at times on the order of one minute. The minimum annealing times and temperatures required for complete transformation of the A-15 phase into the BCC phase varied from sample to sample, indicating that the transformation was dependent on the film characteristics. The electrical resistivity of A-15 Cr and W films was measured before and after rapid thermal annealing and was found to significantly decrease after transformation into the body center cubic phase.

Textures of the Hot-Forged Ti6Al4V Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 111-114
Author(s):  
Adam Bunsch ◽  
Wiktoria Ratuszek ◽  
Małgorzata Witkowska ◽  
Joanna Kowalska ◽  
Aneta Łukaszek-Sołek
Keyword(s):  
Deformation Temperature ◽  
Phase State ◽  
Hexagonal Phase ◽  
Ti6al4v Alloy ◽  
The Body ◽  
Cubic Phase ◽  
Body Centered Cubic ◽  
Two Phase ◽  
Different Temperatures

This paper presents the results of the texture investigation in the hexagonal phase and the body-centered cubic  phase of the Ti6Al4V alloy hot-deformed by forging. Forging was performed at two different temperatures on the occurrence of the single  and in the two-phase  +  state. It was found that after deformation both  and  phases are textured and their textures strongly depends on deformation temperature.

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