Structural behavior of zirconia thin films with different level of yttrium content

2002 ◽  
Vol 756 ◽  
Author(s):  
V. Petrovsky ◽  
H. U. Anderson ◽  
T. Petrovsky ◽  
E. Bohannan

ABSTRACTThe preparation of dense, high conductive electrolyte layers is important for the development of intermediate temperature solid oxide fuel cells and other devices based on oxygen-ion conductivity. Thus a number of techniques have been used to produce these structures. This study makes use of one of these methods to produce dense nanocrystalline 0.1 to 1 micron layers of zirconia.Polymeric precursors were used to prepare zirconia films with different level of yttrium substitution. The films were annealed at a series of temperatures in the range of 400 to 1000°C and were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that initially (after 400°C annealing) the films had cubic structure and grain size of ∼5 nm regardless of Y content. The situation changed when the annealing temperature was increased. Y (16mol %) stabilized zirconia (YSZ) did remain cubic over the entire temperature region investigated (up to 1000°C), but for compositions with lower Y content changes in crystal structure occurred. The samples with 4 and 8mol% Y transformed to the tetragonal phase at about 700°C, and undoped zirconia became monoclinic at the same temperature.The results were compared with sintered zirconia and it was shown that the behavior of thin films is quite similar to that of the sintered material, if the annealing temperature was high enough (>700°C). The main differences between polymeric prepared films and sintered material are the existence of the cubic structure at low temperatures (< 600°C) and lower transition temperatures to the high temperature phase, which can be explained by small initial grain size in polymer-derived zirconia.

1999 ◽  
Vol 77 (7) ◽  
pp. 515-520
Author(s):  
AAI Al-Bassam

Thin film polycrystalline solar cells based on CuIn1–xGaxSe2 have been fabricated and studied with x values from 0 to 1.0. The lattice parameters, grain size, and band gap were measured. Crystal structure and X-ray data of CuIn1–xGaxSe2 were determined using X-ray diffractometry. These materials had a cubic structure with x ≥ 0.5 and a tetragonal structure with x ≤ 0.5. The lattice constants vary linearly with composition. Grain size was measured using X-ray diffraction where the grain size increased linearly with Ga content. A grain size of 1.83-3.52 μm was observed with x ≤ 0.5, while it increased to 4.53 μm for x = 0.58.PACS No.: 70.73


Author(s):  
T. Subba Rao ◽  
B. K. Samantaray ◽  
A. K. Chaudhuri

AbstractThin films of SnSe vacuum deposited on glass substrates kept at different temperatures have been studied by X-ray diffraction. It is observed that the high temperature phase of SnSe, usually found above 807 K is frozen in along with the low temperature phase when deposited at substrate temperatures of 473 K and above.


Author(s):  
J.P.S. Hanjra

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.


1996 ◽  
Vol 52 (a1) ◽  
pp. C364-C364
Author(s):  
J. A. Guevara ◽  
S. L. Cuffini ◽  
Y. P. Mascarenhas ◽  
P. de la Presa ◽  
A. Ayala ◽  
...  

1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.


Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 118 ◽  
Author(s):  
Ho-Yun Lee ◽  
Chi-Wei He ◽  
Ying-Chieh Lee ◽  
Da-Chuan Wu

Cu–Mn–Dy resistive thin films were prepared on glass and Al2O3 substrates, which wasachieved by co-sputtering the Cu–Mn alloy and dysprosium targets. The effects of the addition ofdysprosium on the electrical properties and microstructures of annealed Cu–Mn alloy films wereinvestigated. The composition, microstructural and phase evolution of Cu–Mn–Dy films werecharacterized using field emission scanning electron microscopy, transmission electronmicroscopy and X-ray diffraction. All Cu–Mn–Dy films showed an amorphous structure when theannealing temperature was set at 300 °C. After the annealing temperature was increased to 350 °C,the MnO and Cu phases had a significant presence in the Cu–Mn films. However, no MnO phaseswere observed in Cu–Mn–Dy films at 350 °C. Even Cu–Mn–Dy films annealed at 450 °C showedno MnO phases. This is because Dy addition can suppress MnO formation. Cu–Mn alloy filmswith 40% dysprosium addition that were annealed at 300 °C exhibited a higher resistivity of ∼2100 μΩ·cm with a temperature coefficient of resistance of –85 ppm/°C.


Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.


2019 ◽  
Vol 397 ◽  
pp. 118-124
Author(s):  
Linda Aissani ◽  
Khaoula Rahmouni ◽  
Laala Guelani ◽  
Mourad Zaabat ◽  
Akram Alhussein

From the hard and anti-corrosions coatings, we found the chromium carbides, these components were discovered by large studies; like thin films since years ago. They were pointed a good quality for the protection of steel, because of their thermal and mechanical properties for this reason, it was used in many fields for protection. Plus: their hardness and their important function in mechanical coatings. The aim of this work joins a study of the effect of the thermal treatment on mechanical and structural properties of the Cr/steel system. Thin films were deposited by cathodic magnetron sputtering on the steel substrates of 100C6, contain 1% wt of carbon. Samples were annealing in vacuum temperature interval between 700 to 1000 °C since 45 min, it forms the chromium carbides. Then pieces are characterising by X-ray diffraction, X-ray microanalysis and scanning electron microscopy. Mechanical properties are analysing by Vickers test. The X-ray diffraction analyse point the formation of the Cr7C3, Cr23C6 carbides at 900°C; they transformed to ternary carbides in a highest temperature, but the Cr3C2 doesn’t appear. The X-ray microanalysis shows the diffusion mechanism between the chromium film and the steel sample; from the variation of: Cr, Fe, C, O elements concentration with the change of annealing temperature. The variation of annealing temperature shows a clean improvement in mechanical and structural properties, like the adhesion and the micro-hardness.


2018 ◽  
Vol 24 (S1) ◽  
pp. 2248-2249
Author(s):  
M. Ramírez-Cardona ◽  
M.P. Falcón-León ◽  
G. Luis-Raya ◽  
G. Mejía-Hernández ◽  
R. Arceo ◽  
...  

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