Single Crystal Zirconia Thin Films from Liquid Precursors

1989 ◽  
Vol 155 ◽  
Author(s):  
K. T. Miller ◽  
F. F. Lange

ABSTRACTEpitaxial, single-crystal films of ZrO2 (Y2O3) were formed on (100) oriented single crystal substrates of ZrO2 (9.5 mol% Y2O3) using water-based solutions of zirconium acetate and yttrium nitrate as a precursor. Film compostions of ZrO2 (0 - 40 mol% Y2O3) were examined; since the lattice parameter of ZrO2 (Y2O3) increases with yttria content, the lattice mismatch was systematically varied to a maximum of 1.5%. Precursor films were deposited by spin coating, pyrolyzed, and held for 1 hour at 900°C, 1000°C, and 1100°C. X-ray diffraction showed that a strongly oriented film had developed after pyrolysis of the precursor. In addition, all samples, except those treated at 1100°C containing 6 – 15 mol% Y2O3, gave (111) peaks, indicating film polycrystallinity. Electron back-scattering patterns showed that epitaxial single crystals were formed at 1100°C for films containing 3 – 20 mol% Y2O3. Scanning electron microscopy showed that the epitaxial films had a porous structure. These results indicate that the epitaxy is a two-stage process: oriented nucleation upon pyrolysis, followed, for low mismatches, by subsequent consolidation into a single-crystal film above 1000°C.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.


2007 ◽  
Vol 539-543 ◽  
pp. 3059-3063 ◽  
Author(s):  
G. Schumacher ◽  
N. Darowski ◽  
I. Zizak ◽  
Hellmuth Klingelhöffer ◽  
W. Chen ◽  
...  

The profiles of 001 and 002 reflections have been measured at 1173 K as a function of time by means of X-ray diffraction (XRD) on tensile-creep deformed specimens of single crystal superalloy SC16. Decrease in line width (full width at half maximum: FWHM) by about 7 % and increase in peak position by about 3x10-4 degrees was detected after 8.5x104 s. Broadening of the 002 peak profile indicated a more negative value of the lattice misfit after the same time period. The results are discussed in the context of the anisotropic arrangement of dislocations at the γ/γ’ interfaces during creep and their rearrangement during the thermal treatment at 1173 K.


2018 ◽  
Vol 941 ◽  
pp. 2093-2098
Author(s):  
Naho Itagaki ◽  
Kazuto Takeuchi ◽  
Nanoka Miyahara ◽  
Kouki Imoto ◽  
Hyun Woong Seo ◽  
...  

We studied effects of sputtering pressure on growth of (ZnO)x(InN)1-xcrystal films deposited at 450°C by rf magnetron sputtering. Epitaxial growth of (ZnO)x(InN)1-xfilms was realized on single-crystalline ZnO template. X-ray diffraction measurements show that full width at half maximum of the rocking curves from the (101) plane of the films reaches minimum value of 0.11º at 0.5 Pa. The sputtering gas pressure is a key tuning knob for controlling the crystal quality of ZION films.


1995 ◽  
Vol 401 ◽  
Author(s):  
P. A. Langjahr ◽  
T. Wagner ◽  
M. RÜhle ◽  
F. F. Lange

AbstractCubic and pseudocubic perovskite films on perovskite substrates are used to study the influence of the lattice mismatch on the epitaxial growth of thin films on substrates of the same structure. For the growth of the films, a metalorganic decomposition route (MOD) using 2-ethylhexanoates and neodecanoates as precursors, was developed. The decomposition of the precursors was investigated with thermogravimetric analysis (TGA) and x-ray diffraction (XRD). The films were spin-coated on (001)-oriented SrTiO3- and LaAlO3-substrates, pyrolyzed and afterwards annealed between 600°C and 1200°C. XRD-nvestigations and conventional transmission electron microscopy (CTEM) show, that epitaxial films with the orientation relationship [100](001) film ║ [100](001) substrate can be grown. With XRD, it could be shown, that not only ternary oxide films (SrZrO3, BaZrO3 and BaCeO3), but also perovskite solid solution films (SrTi0.5Zr0.5O3and BaCe0.5Zr0.5O3) can be prepared. Strong interdiffusion, detected by a shift of the film lattice parameter towards the substrate lattice parameter was found in SrZrO3- and BaZrO3-films on SrTiO3, annealed at temperatures above 1050°C. High resolution electron microscopy (HREM) studies of SrZrO3 on SrTiO3 show that a crystalline semicoherent interface with a periodical array of misfit dislocations is present.


2021 ◽  
Vol 42 (11) ◽  
pp. 112001
Author(s):  
Yifan Wang ◽  
Xuanze Li ◽  
Pei Liu ◽  
Jing Xia ◽  
Xiangmin Meng

Abstract Epitaxial high-crystallization film semiconductor heterostructures has been proved to be an effective method to prepare single-crystal films for different functional devices in modern microelectronics, electro-optics, and optoelectronics. With superior semiconducting properties, halide perovskite materials are rising as building blocks for heterostructures. Here, the conformal vapor phase epitaxy of CsPbBr3 on PbS single-crystal films is realized to form the CsPbBr3/PbS heterostructures via a two-step vapor deposition process. The structural characterization reveals that PbS substrates and the epilayer CsPbBr3 have clear relationships: CsPbBr3(110) // PbS(100), CsPbBr3[ ] // PbS[001] and CsPbBr3[001] // PbS[010]. The absorption and photoluminescence (PL) characteristics of CsPbBr3/PbS heterostructures show the broadband light absorption and efficient photogenerated carrier transfer. Photodetectors based on the heterostructures show superior photoresponsivity of 15 A/W, high detectivity of 2.65 × 1011 Jones, fast response speed of 96 ms and obvious rectification behavior. Our study offers a convenient method for establishing the high-quality CsPbBr3/PbS single-crystal film heterostructures and providing an effective way for their application in optoelectronic devices.


2008 ◽  
Vol 23 (12) ◽  
pp. 3281-3287 ◽  
Author(s):  
George H. Thomas ◽  
Eliot D. Specht ◽  
John Z. Larese ◽  
Ziling B. Xue ◽  
David B. Beach

Epitaxial films of sodium potassium tantalate (Na0.5K0.5TaO3, NKT) and sodium potassium niobate (Na0.5K0.5NbO3, NKN) were grown on single-crystal lanthanum aluminate (LAO) (100) (indexed as a pseudo-cubic unit cell) substrates via an all-alkoxide solution (methoxyethoxide complexes in 2-methoxyethanol) deposition route for the first time. X-ray diffraction studies indicated that the onset of crystallization in powders formed from hydrolyzed gel samples was 550 °C. 13C nuclear magnetic resonance studies of solutions of methoxyethoxide complexes indicated that mixed-metal species were formed, consistent with the low crystallization temperatures observed. Thermal gravimetric analysis with simultaneous mass spectrometry showed the facile loss of the ligand (methoxyethoxide) at temperatures below 400 °C. Crystalline films were obtained at temperatures as low as 650 °C when annealed in air. θ-2θ x-ray diffraction patterns revealed that the films possessed c-axis alignment in that only (h00) reflections were observed. Pole-figures about the NKT or NKN (220) reflection indicated a single in-plane, cube-on-cube epitaxy. The quality of the films was estimated via ω (out-of-plane) and φ (in-plane) scans and full-widths at half-maximum (FWHMs) were found to be reasonably narrow (∼1°), considering the lattice mismatch between the films and the substrate.


2018 ◽  
Vol 74 (8) ◽  
pp. 917-922
Author(s):  
Hisanori Yamane ◽  
Keita Hiraka

Single crystals of the filled Ti2Ni-type Ti3Zn3O x η-phase (cubic, space group Fd\overline{3}m) having {111} facets were obtained by heating Ti, Zn and ZnO with a Bi flux. The lattice parameter of a single crystal prepared at 800°C was 11.4990 (2) Å, which is close to that of Ti3Zn3O∼0.5 (a = 11.502 Å), as reported by Rogl & Nowotny [Monatsh. Chem. (1977), 108, 1167–1180]. The occupancies of the O1 (16c) and O2 (8a) sites were 1 and 0.071 (12), respectively, and the composition of the crystal was determined to be Ti3Zn3O1.04. A single crystal from the sample prepared at 650°C had the same structure type, with a lattice parameter of 11.5286 (2) Å. However, O atoms were situated at a new 32e site in addition to the original 16c and 8a sites, and the Zn-atom positions were split in accordance with the new O-atom site. The chemical formula Ti3Zn3O1.27 determined by X-ray diffraction occupancy refinement agreed with the chemical composition obtained for the cross section of the single crystal determined with an electron probe microanalyzer.


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