Polycrystalline Lead Iodide Films: Optical, Electrical and X-ray Counting Characterization

2001 ◽  
Vol 685 ◽  
Author(s):  
L. Fornaro ◽  
E. Saucedo ◽  
L. Mussio ◽  
A. Gancharov ◽  
F. Guimaraes ◽  
...  

AbstractLead iodide purified by zone refining and repeated sublimation was used for growing Polycrystalline films by physical vapor deposition. Palladium film was deposited as rear contact onto glass and alumina substrates 2.5 × 2.5 cm2 in size. Onto it, lead iodide polycrystalline films were grown by sublimation at 390 °C and 5 × 10−5 mm Hg, substrate temperatures of about 200 °C and deposition times of about 10 days. Film thickness was measured by X-ray transmission at 59.5 keV giving values from 35 to 50 μm (5%). Optical and atomic force microscopy were performed to the films giving an average grain size of (80±20) μm. Low temperature photoluminescence was performed and peak position and broadness confirmed the high purity of starting materials. Films were characterized by X-ray diffraction, giving an [ΣI (0 0 l)] / [ΣI (h k l)] relation of 0.8 that indicates a strong growth preferred orientation along c axis. Front palladium thermal deposition contacts and acrylic encapsulation were done and apparent resistivity (2 × 1014 Ω. cm) and current density (7 pA/cm2 (30 V)) were obtained. X-ray film response was checked by irradiating with 241Am and an X-ray beam. Finally, film and detector characterizations were correlated with starting material, deposition parameters and previous results for the same and alternative materials like mercuric iodide.

1997 ◽  
Vol 485 ◽  
Author(s):  
Chih-hung Chang ◽  
Billy Stanbery ◽  
Augusto Morrone ◽  
Albert Davydov ◽  
Tim Anderson

AbstractCuInSe2 thin films have been synthesized from binary precursors by Rapid Thermal Processing (RTP) at a set-point temperature of 290°C for 70 s. With appropriate processing conditions no detrimental Cu2-xSe phase was detected in the CIS films. The novel binary precursor approach consisted of a bilayer structure of In-Se and Cu-Se compounds. This bilayer structure was deposited by migration enhanced physical vapor deposition at a low temperature (200°C) and the influence of deposition parameters on the precursor film composition was determined. The bilayer structure was then processed by RTP and characterized for constitution by X-ray diffraction and for composition by Wavelength Dispersive X-ray Spectroscopy.


Cerâmica ◽  
2002 ◽  
Vol 48 (305) ◽  
pp. 38-42 ◽  
Author(s):  
M. I. B. Bernardi ◽  
E. J. H. Lee ◽  
P. N. Lisboa-Filho ◽  
E. R. Leite ◽  
E. Longo ◽  
...  

The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperature of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.


2005 ◽  
Vol 19 (12) ◽  
pp. 2073-2083 ◽  
Author(s):  
P. LIMSUWAN ◽  
N. UDOMKAN ◽  
S. MEEJOO ◽  
P. WINOTAI

Aluminium nitride (AlN) thin films were fabricated on a glass substrate by reactive magnetron sputtering. Raman microscopy was then employed to follow the characteristics of their optical and acoustic phonon modes. At the optimal sputtering time of 30 minutes, the defect-induced first and second order Raman spectra were observed in 400–800 cm-1 band which were mostly related to the coating compositions. However, at the 30-, 60- and 90-minute sputtering, crystals of submicron size order of AlN were achieved. This could be clearly identified by the presence of Raman peak at 658–662 cm-1. Powder X-ray diffraction (PXRD) patterns revealed the development of (002) and (101) planes of hexagonal wurtzite AlN phase. The optimal average grain size measured by atomic force microscopy (AFM) is at 330 nm. It was found that the hardness was strongly dependent on roughness of the film, the maximum of which was achieved at 20.00 GPa. The presence of F-type defects in AlN films was investigated by X-band (~9.44 GHz) ESR spectrometer at 295 K. The ESR experiments were carried out by applying magnetic field perpendicular to AlN film, which showed the ESR six-peak multiplet signal at ~290 mT arising from superhyperfine interactions between nuclear spin I = 5/2 of 27 Al and electron spins trapped in nitrogen vacancies. The ESR signals are simulated and the ESR parameters are calculated. The vacancies are clearly randomly distributed as the ESR signals are independent of rotation angle (φ) about the normal of the film. All these results were analyzed and presented as a function of the deposition parameters and composition, and crystalline phases existed in the films.


1994 ◽  
Vol 359 ◽  
Author(s):  
S. Henke ◽  
B. Rauschenbach ◽  
B. Stritzker

ABSTRACTBy deposition of C60 on silicon at moderate temperatures (800°C … 900°C) the formation of thin epitaxial β-SiC-films on Si could be proved. C60 -molecules were deposited onto Si(001) and Si(111) in high-vacuum at constant deposition rates for some hours. The thickness and the composition of the formed layers are determined by Rutherford-Backscattering (RBS). The thickness of the layers varied between about 50nm and 200nm in dependence of the deposition parameters. From the shape of the RBS-spectra only β-SiC can be identified. SiC-grains with a mean size of about 500 nm have been observed by atomic force microscopy (AFM). X-ray diffraction (XRD) pole figure measurements demonstrate the heteroepitaxial growth of β-SiC on Si It can be shown by XRD that only the cubic structure (β-SiC) of the different polytypes of SiC was formed during the carbonization process. The formation of growth defects (twins) can be observed.


Cerâmica ◽  
2002 ◽  
Vol 48 (308) ◽  
pp. 192-198 ◽  
Author(s):  
M. I. B. Bernardi ◽  
E. J. H. Lee ◽  
P. N. Lisboa-Filho ◽  
E. R. Leite ◽  
E. Longo ◽  
...  

In this work we report the synthesis of TiO2 thin films by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during the growth in the obtained structural characteristics was studied. Different temperatures of the organometallic bath, deposition time, temperature and type of the substrate were combined. Using Scanning Electron Microscopy associated to Electron Dispersive X-Ray Spectroscopy, Atomic Force Microscopy and X-ray Diffraction, the strong influence of these parameters in the thin films final microstructure was verified.


2007 ◽  
Vol 994 ◽  
Author(s):  
Jose Fernando Condeles ◽  
Ademar Marques Caldeira-Filho ◽  
Marcelo Mulato

AbstractSpray pyrolysis was used for the deposition of lead iodide (PbI2) thin films using N.N-dimethylformamide (DMF) as an alternative solvent under varying deposition parameters. Final thickness of 60 μm was obtained for a total deposition time of 2.5 hours. The films were characterized mainly by using Raman and photoluminescence, but additional techniques such as X-ray diffraction, scanning electron microscopy and dark conductivity as a function of temperature were also employed. Thick PbI2 films deposited by spray pyrolysis using DMF as a solvent are promising to be used in medical systems as X-ray imaging.


2019 ◽  
Vol 12 (25) ◽  
pp. 69-79
Author(s):  
Hind Mohammed Hasan

Ferrite with general formula Ni1-x Cox Fe2O4(where x=0.0.1,0.3,0.5,0.7, and 0.9), were prepared by standard ceramic technique. The main cubic spinel structure phase for all samples was confirmed by x-ray diffraction patterns. The lattice parameter results were (8.256-8.299 °A). Generally, x -ray density increased with the addition of Cobalt and showed value between (5.452-5.538gm/cm3). Atomic Force Microscopy (AFM) showed that the average grain size and surface roughness was decreasing with the increasing cobalt concentration. Scanning Electron Microscopy images show that grains had an irregular distribution and irregular shape. The A.C conductivity was found to increase with the frequency and the addition of Cobalt, D.C conductivity was found to increase with temperature due to decreases in resistivity. Dielectric constants were noticed to decrease with frequency and Co addition. The Hall coefficient was found to be positive. This demonstrates that the majority of charge carriers are p-type, suggesting that the mechanism of conduction is predominantly caused by hopping of holes.


2019 ◽  
Vol 11 (22) ◽  
pp. 102-109
Author(s):  
Muthafar F. Al- Hilli

        Ferrite with the general formula CuLayFe2-yO4 (where y=0.02, 0.04, 0.06, 0.08 and 0.1), were prepared by standard ceramic technique. The main cubic spinel structure phase for all samples was confirmed by x-ray diffraction patterns with the appearance of small amount of secondary phases. The lattice parameter results were 8.285-8.348 Å. X-ray density increased with La addition and showed values between 5.5826 – 5.7461gm/cm3. The Atomic Force Microscopy (AFM) showed that the average grain size was decreasing with the increase in La concentration. The Hall coefficient was found to be positive. It demonstrates that the majority of charge carriers of p-type, suggesting that the mechanism of conduction is predominantly caused by hopping of holes. The resistivity was noticed to increase with the increase in La substitution. The activation energy Eav decreased with the frequency increase. The AC conductivity was found to increase with the frequency and La addition. Dielectric constant was noticed to decrease with frequency and La addition. The dielectric loss factor decreased with La content because rare earths are known as low dielectric loss materials.


2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.


Author(s):  
Michael DiBattista ◽  
Kimball Skinner ◽  
Rick Kneedler ◽  
Leonid Vasilvey ◽  
Lukas Drybcak ◽  
...  

Abstract Circuit edit and failure analysis require tungsten deposition parameters to accomplish different goals. Circuit edit applications desire low resistivity values for rewiring, while failure analysis requires high deposition rates for capping layers. Tungsten deposition can be a well controlled process for a variety of beam parameters. For circuit edit, tungsten resistivity approaching below 150 µohm-cm and 50 μm3/nC is predicted. Material deposition rates of 80 μm3/nC can be achieved with reasonable pattern accuracy using defocus as a parameter.


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