Epitaxial Piezoelectric Langasite Thin Films for High-Temperature Application

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 523-529
Author(s):  
Hendrik Wulfmeier ◽  
René Feder ◽  
Li Zhao ◽  
Holger Fritze

ABSTRACTThe homo- and heteroepitaxial deposition of LGS (langasite, La3Ga5SiO14) thin films on LGS single crystals, Si and SiO2 substrates by pulsed laser deposition (PLD) is demonstrated. PLD is performed at substrate temperatures up to about 700 °C and results initially in Ga deficient films. Two strategies of counterbalancing the Ga deficit are realized. First, off-stoichiometric targets with an enhanced Ga content are applied. Secondly, an increased oxygen partial pressure up to about 6 Pa is used during deposition to suppress evaporation of Ga suboxides. Combining these adaptions results in the growth of stoichiometric LGS thin films. Films deposited on LGS substrates do not show any additional X-ray diffraction reflexes nor broadening of the peaks with respect to the single crystalline substrates. Therefore, the homoepitaxial approach can be considered successful. The deposition on Si and SiO2 substrates under the same conditions leads to the formation of polycrystalline films. However, post-annealing at 800 °C increases crystallinity. Stoichiometry and homogeneous distribution of La, Ga and Si cations are confirmed by secondary neutral mass spectrometry (SNMS). The composition remains constant within the film, implying stable process parameters.

1989 ◽  
Vol 169 ◽  
Author(s):  
F.H. Garzon ◽  
J. G. Beery ◽  
D. K. Wilde ◽  
I. D. Raistrick

AbstractThin films of Y‐Ba‐Cu‐O were produced by RF sputtering of YBa2Cu3O7‐x ceramic targets, using a variety of plasma compositions, RF power levels, and substrate temperatures. Post annealing of these films in oxygen produced superconducting films with Tc values between 40‐60 K, broad transition widths and semiconductor‐like electrical behavior above Tc. Subsequent annealing at 850°C in an inert gas with a residual oxygen partial pressure of ≤10 ppm followed by an oxygen anneal produced high quality thin films: Tc> 85 K with narrow transition widths. The structure and morphology of these films during reduction‐oxidation processing were monitored using X‐ray diffraction and electron microscopy.


Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.


2012 ◽  
Vol 90 (1) ◽  
pp. 39-43 ◽  
Author(s):  
X. Xiang ◽  
D. Chang ◽  
Y. Jiang ◽  
C.M. Liu ◽  
X.T. Zu

Anatase TiO2 thin films are deposited on K9 glass samples at different substrate temperatures by radio frequency magnetron sputtering. N ion implantation is performed in the as-deposited TiO2 thin films at ion fluences of 5 × 1016, 1 × 1017, and 5 × 1017 ions/cm2. X-ray diffraction, atomic force microscope, X-ray photoelectron spectroscopy (XPS), and UV–visible spectrophotometer are used to characterize the films. With increasing N ion fluences, the absorption edges of anatase TiO2 films shift to longer wavelengths and the absorbance increases in the visible light region. XPS results show that the red shift of TiO2 films is due to the formation of N–Ti–O compounds. As a result, photoactivity is enhanced with increasing N ion fluence.


2011 ◽  
Vol 1328 ◽  
Author(s):  
KyoungMoo Lee ◽  
Yoshio Abe ◽  
Midori Kawamura ◽  
Hidenobu Itoh

ABSTRACTCobalt hydroxide thin films with a thickness of 100 nm were deposited onto glass, Si and indium tin oxide (ITO)-coated glass substrates by reactively sputtering a Co target in H2O gas. The substrate temperature was varied from -20 to +200°C. The EC performance of the films was investigated in 0.1 M KOH aqueous solution. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy of the samples indicated that Co3O4 films were formed at substrate temperatures above 100°C, and amorphous CoOOH films were deposited in the range from 10 to -20°C. A large change in transmittance of approximately 26% and high EC coloration efficiency of 47 cm2/C were obtained at a wavelength of 600 nm for the CoOOH thin film deposited at -20°C. The good EC performance of the CoOOH films is attributed to the low film density and amorphous structure.


2007 ◽  
Vol 124-126 ◽  
pp. 451-454 ◽  
Author(s):  
Jung Min Kim ◽  
Hyun Jung Her ◽  
J.H. Yoon ◽  
Jae Wan Kim ◽  
Y.J. Choi ◽  
...  

We investigated the characteristics of pentacene thin films of different materials for gate insulators using atomic force microscope (AFM) and x-ray diffraction (XRD). The pentacene thin films are fabricated by evaporation on different polymer substrates. We used HMDS (Hexa Methyl Di Silazane), PVA (Poly Vinyl Alcohol) and PMMA (Poly Methyl Meth Acrylate) for the polymer substrates, on which pentacene is deposited at various substrate temperatures. The case of pentacene deposited on the PMMA has the largest grain size and least trap concentration. We also fabricated pentacene TFTs with the PMMA gate insulator. Pentacene TFTs with PMMA gate insulator, shows high field-effect mobility (uFET= 0.03 cm2/Vs) and large on/off current ratio (>105) and small threshold voltage (Vth= -6 V).


2013 ◽  
Vol 743-744 ◽  
pp. 910-914
Author(s):  
Ting Han ◽  
Geng Rong Chang ◽  
Yun Jin Sun ◽  
Fei Ma ◽  
Ke Wei Xu

Si/C multilayer thin films were prepared by magnetron sputtering and post-annealing in N2 atmosphere at 1100 for 1h. X-ray diffraction (XRD), Raman scattering and high-resolution transmission electron microscopy (HRTEM) were applied to study the microstructures of the thin films. For the case of Si/C modulation ratio smaller than 1,interlayer diffusion is evident, which promotes the formation of α-SiC during thermal annealing. If the modulation ratio is larger than 1, the Si sublayers are partially crystallized, and the thicker the Si sublayers are, the crystallinity increases. To be excited, brick-shaped nc-Si is directly observed by HRTEM. The brick-shaped nc-Si appears to be more regular near the Si (100) substrate but with twin defects. The results are instructive in the application of solar cells.


1992 ◽  
Vol 242 ◽  
Author(s):  
W. J. Meng ◽  
T. A. Perry ◽  
J. Heremans ◽  
Y. T. Cheng

ABSTRACTThin films of aluminum nitride were grown epitaxially on Si(111) by ultra-high-vacuum dc magnetron reactive sputter deposition. Epitaxy was achieved at substrate temperatures of 600° C or above. We report results of film characterization by x-ray diffraction, transmission electron microscopy, and Raman scattering.


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


2017 ◽  
Vol 268 ◽  
pp. 229-233
Author(s):  
A.R. Nurhamizah ◽  
Zuhairi Ibrahim ◽  
Rosnita Muhammad ◽  
Yussof Wahab ◽  
Samsudi Sakrani

This research aims to study the growth and the effect of annealing temperature on the structural properties of Platinum/YSZ/Platinum thin film. The thin films were prepared by RF and DC magnetron sputtering method utilized platinum as electrodes (anode and cathode) and YSZ as electrolyte. Two temperatures of annealing (400 and 600 °C) were conducted onto Platinum/YSZ/Platinum thin film for comparison in this study. Crystalline phase, microstructure and thickness of thin films were evaluated using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FE-SEM) technique. Results show that Pt/YSZ/Pt thin film without post-annealing gives a better morphology and crystal phase.


1999 ◽  
Vol 602 ◽  
Author(s):  
W. Prellier ◽  
Amlan Biswas ◽  
M. Rajeswari ◽  
T. Venkatesan ◽  
R.L. Greene

AbstractWe report the growth and characterization of Nd0.5Sr0.5MnO3 thin films deposited by the Pulsed Laser Deposition (PLD) technique on [100]-oriented LaAlO3 substrates. X-ray diffraction (XRD) studies show that the films are [101]-oriented, with a strained and quasi-relaxed component, the latter increasing with film thickness. A post-annealing under oxygen leads to a quasi-relaxed film with a metallic behavior. We also observe that transport properties are strongly dependent on the thickness of the films. Variable temperature XRD down to 100 K suggests that this is caused by substrate-induced strain on the films.


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