Optical Waveguides Using Epitaxial Bi4Ti3O12 Thin Films on MgO with CeO2 Cladding Layers

1995 ◽  
Vol 401 ◽  
Author(s):  
William Jo ◽  
T. W. Noh ◽  
Y. T. Byun ◽  
S. H. Kim
Keyword(s):  
Thin Films ◽  
Optical Waveguides ◽  
Near Field ◽  
Single Mode ◽  
Field Pattern ◽  
X Ray Diffraction ◽  
Ion Milling ◽  
Epitaxial Relationship ◽  
Relationship Of ◽  
Cladding Layers

AbstractCeO2 thin films were grown on MgO(001) single-crystal substrates by pulsed laser deposition. The CeO2 thin films were used as a cladding layer of a Bi4Ti3O12 thin film waveguide. Structural properties of the BTO/CeO2/MgO heterostructures were investigated using x-ray diffraction techniques. An epitaxial relationship of BTO(001)//CeO2(001)// MgO(001) and BTO[100]//CeO2[100]//MgO[001] was confirmed. From the epitaxial heterostructure, a ridge waveguide was fabricated by photolithographic and ion-milling techniques. An single-mode near-field pattern was observed using an end-fire coupling method.

Microstructural Studies of Ferroelectric Bi2VO5.5 Thin Films With LaNiO3 Electrodes

1994 ◽  
Vol 341 ◽  
Author(s):  
D. Prasad Beesabathina ◽  
L. Salmanca-Riba ◽  
M. S. Hegde ◽  
K. M. Satyalakshmi ◽  
K. V. R. Prasad ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Direction ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Transmission Electron ◽  
Lattice Images ◽  
Relationship Of ◽  
Microstructural Studies

AbstractThin films of Bi2VO5.5 (BVO), a vanadium analog of the n = I member of the Aurivillius family, have been prepared by pulsed laser deposition. The BVO films grow along the [001] direction on LaNiO3(LNO) and YBa2Cu3O7 (YBCO) electrode buffer layers on LaA- IO3(LAO) substrates as obtained from X-ray diffraction studies. The microstructure of the films and of the interfaces within the film and between the film and the substrate were characterized using transmission electron microscopy. The in-plane epitaxial relationship of the rhombohedral LNO on perovskite LAO was [100] LNO // [100] LAO and [001] LNO // [001] LAO. High resolution lattice images showed a sharp interface between LNO and LAO. However, the LNO film is twinned with a preferred orientation along the growth direction. The BVO layer is single crystalline on both LNO/LAO and YBCO/LAO with the caxis parallel to the growth direction except for a thin layer of about 400 Å at the interface which is polycrystalline.

Room-temperature growth of ultrasmooth AlN epitaxial thin films on sapphire with NiO buffer layer

2004 ◽  
Vol 19 (9) ◽  
pp. 2725-2729 ◽  
Author(s):  
Atsushi Sasaki ◽  
Jin Liu ◽  
Wakana Hara ◽  
Shusaku Akiba ◽  
Keisuke Saito ◽  
...  
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Room Temperature ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
Heteroepitaxial Structure ◽  
Temperature Growth ◽  
X Ray ◽  
Relationship Of

Room-temperature epitaxy of AlN thin films on sapphire (0001) substrates was achieved by pulsed laser deposition using an epitaxial NiO ultrathin buffer layer (approximately 6 nm thick). Four-circle x-ray diffraction analysis indicates a double heteroepitaxial structure of AlN (0001)/NiO(111)/sapphire (0001) with the epitaxial relationship of AlN [10-10] ‖ NiO [11-2] ‖ sapphire [11-20]. The surface morphology of room-temperature grown AlN thin films was found to be atomically smooth and nanostepped, reflecting the surface of the ultrasmooth sapphire substrate with 0.2-nm-high steps.

The process and mechanism of the GaN nanoparticles formed by nitridation of β-Ga2O3 crystal

2017 ◽  
Vol 31 (10) ◽  
pp. 1750108 ◽  
Author(s):  
Xiao-Jun Cui ◽  
Liang-Ling Wang
Keyword(s):  
Vapor Deposition ◽  
Surface Defect ◽  
Chemical Vapor ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
X Ray ◽  
Diffraction Peaks ◽  
Relationship Of ◽  
Gan Film

The process of conversion from [Formula: see text]-Ga2O3 single crystal to gallium nitride (GaN) in an atmosphere of NH3 by chemical vapor deposition is investigated. The surface morphology and microstructure of the GaN nanoparticles are observed by scanning electron microscope, which indicates that the growth of GaN is via the Volmer–Weber mechanism. The [Formula: see text]-Ga2O3 is firstly evaporated at high temperature to form the porous layer, followed by the surface-defect induced GaN nucleation formation. The crystalline structure and epitaxial relationship of the GaN nanoparticles are investigated by X-ray diffraction (XRD) via [Formula: see text]–[Formula: see text], showing GaN (0002) and (0004) diffraction peaks in the XRD spectra. It is concluded that the polycrystalline GaN film with hexagonal structure has a strong c-axis preferential orientation.

Epitaxial BaTiO3 Thin Films on Different Substrates for Optical Waveguide Applications

1999 ◽  
Vol 597 ◽  
Author(s):  
M. Siegert ◽  
Judit G. Lisoni ◽  
C. H. Lei ◽  
A. Eckau ◽  
W. Zander ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Waveguides ◽  
Rutherford Backscattering Spectrometry ◽  
Optical Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Ion Channeling ◽  
Atomic Force ◽  
Transmission Electron

AbstractIn the process of developing thin film electro-optical waveguides we investigated the influence of different substrates on the optical and structural properties of epitaxial BaTiO3 thin films. These films are grown by on-axis pulsed laser deposition (PLD) on MgO(100), MgAl2O4(100), SrTiO3(100) and MgO buffered A12O3(1102) substrates. The waveguide losses and the refractive indices were measured with a prism coupling setup. The optical data are correlated to the results of Rutherford backscattering spectrometry/ion channeling (RBS/C). X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). BaTiO3 films on MgO(100) substrates show planar waveguide losses of 3 dB/cm and ridge waveguide losses of 5 dB/cm at a wavelength of 633 nm.

Preparation of epitaxial SrBi2Nb2O9 and SrBi2Ta2O9 thin films by the coating-pyrolysis process

1999 ◽  
Vol 14 (7) ◽  
pp. 3090-3095 ◽  
Author(s):  
T. Nagahama ◽  
T. Manabe ◽  
I. Yamaguchi ◽  
T. Kumagai ◽  
S. Mizuta ◽  
...  
Keyword(s):  
Thin Films ◽  
Epitaxial Films ◽  
Yttria Stabilized Zirconia ◽  
Pyrolysis Process ◽  
Stabilized Zirconia ◽  
Epitaxial Relationship ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polycrystalline Thin Films ◽  
Relationship Of

Epitaxial and polycrystalline thin films of bismuth layer-structured ferroelectrics, SrBi2Nb2O9 (SBN) and SrBi2Ta2O9 (SBT), were prepared on single-crystal SrTiO3(001) and polycrystalline yttria-stabilized zirconia substrates, respectively, by the coating-pyrolysis process. The epitaxial relationship of the films and substrates was SBN, SBT (001)//SrTiO3(001) and SBN, SBT [100]//SrTiO3[100],[010], where pseudotetragonal indices were adopted for SBN and SBT. The lattices of the epitaxial films were found to be slightly strained owing to stress from the substrate. Atomic force microscopy observations showed that the epitaxial films as well as polycrystalline films consisted of round-shaped, islandlike grains of submicrometer size.

Investigations on Integrated Optical Interference Couplers in PMMA for Visible and Infrared Range Fabricated by “Direct Writing” Excimer Laser Radiation

2019 ◽  
Vol 40 (2) ◽  
pp. 149-160
Author(s):  
Humza Mirza ◽  
Bin Wu ◽  
Sabine Tiedeken ◽  
Volker Braun ◽  
Hans Josef Brückner ◽  
...  
Keyword(s):  
Laser Radiation ◽  
Excimer Laser ◽  
Optical Waveguides ◽  
Near Field ◽  
Single Mode ◽  
Structure Design ◽  
Infrared Range ◽  
Direct Writing ◽  
Direct Laser ◽  
Excimer Laser Radiation

Abstract Optical waveguides were generated in Polymethylmethacrylate using “direct” laser and contact mask structuring. Excimer laser radiation (248 nm) produced a local refractive index increase thereby achieving light guiding in waveguides with widths from 2 to 15 $\mu$m. The near field output images were analyzed using visible and infrared laser light. The mode fields of single mode structures were evaluated to elaborate numerically the parameters of the index profile. An index increase up to 0.01 could be achieved using laser pulses at fluences below $0.15$ ${\textrm{J/cm}^{2}}$. Thus it was possible to design interference couplers of 5 $\mu$m waveguides width for the visible (635 nm to 670 nm) as well as for the infrared range at 1550 nm. The coupling properties as a function of the waveguide separation and the wavelength is investigated and found compatible with numerical simulations for the structure design. The presented approach allows for designing and fabricating single mode couplers in an efficient and simple manner.

ENHANCED DIELECTRIC CHARACTERISTICS OF MANGANESE-DOPED BZT THIN FILMS

2008 ◽  
Vol 15 (01n02) ◽  
pp. 29-33 ◽  
Author(s):  
J. ZHU ◽  
W. J. JIE ◽  
X. H. WEI ◽  
W. F. QIN ◽  
Y. ZHANG ◽  
...  
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Figure Of Merit ◽  
Growth Conditions ◽  
Dielectric Behavior ◽  
X Ray Diffraction ◽  
Dielectric Characteristics ◽  
Mn Doping ◽  
X Ray ◽  
Relationship Of

Ba ( Zr 0.2 Ti 0.8) O 3 (BZT) and 2 mol% Mn additional doped BZT ( Mn -BZT) thin films were deposited by pulsed laser deposition technique under the same growth conditions on LaAlO 3 substrates with the bottom electrodes of LaNiO 3. The microstructure of the films was characterized by X-ray diffraction (XRD) in the mode of θ–2θ scan and Φ-scan. The results indicated that BZT film was (001)-oriented_with an in-plane relationship of BZT[100]//LNO[100]//LAO[100]. The Mn -BZT film exhibited higher dielectric constant of 225 at zero electric field, larger dielectric tunability of 59.4%, and lower dielectric loss of 1.8% under an applied electric field of 720 kV/cm. The figure of merit for BZT thin film increased from 19.8 to 33 by Mn doping. The enhanced dielectric behavior by Mn doping could be mainly attributed to the decrease of oxygen vacancies and the reorientation of the dipolar defect complex of [Formula: see text].

Structure-Property Relationship of Ion-Beam Sputtered Nd-Fe-B Magnetic Thin Films On (111) Silicon

1994 ◽  
Vol 354 ◽  
Author(s):  
Anthony S. Nazareth ◽  
Harsh Deep Chopra ◽  
D. K. Sood ◽  
R. B. Zmood
Keyword(s):  
Thin Films ◽  
Ion Beam ◽  
Magnetic Thin Films ◽  
Misfit Strain ◽  
Crystallographic Structure ◽  
Nominal Composition ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Relationship Of

AbstractA focussing grid broad beam Kaufman source, using argon ions on a target of nominal composition Nd2Fei4B has been employed to sputter deposit magnetic thin films of thicknesses ranging from 800 â to 1300 â on silicon-(lll) substrates at room temperature. These films were characterised for their composition depth profile by Rutherford Backscattering Spectroscopy, while x-ray diffraction was used to study the crystallographic structure. Due to a close match between (111) Si with (220) Nd2Fej4B lattice spacings, preferred crystallographic texturing was expected, and experimental results showed a greatly enhanced (220) texture. The degradation in magnetic properties was attributed to the presence of oxygen in the films as indicated by concentration depth profiles. It is premised that another significant role of oxygen may be to relieve the misfit strain across the interface by its incorporation within the Nd2Fej4B phase.

Two conductive mechanisms in LaMnO3 thin film: Adiabatic and nonadiabatic small polaronic hopping

2021 ◽  
pp. 2150310
Author(s):  
Weiyuan Wang ◽  
Jiyu Fan ◽  
Huan Zheng ◽  
Jing Wang ◽  
Hao Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Theoretical Models ◽  
Magnetic Phase Transitions ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
Epitaxial Relationship ◽  
Reciprocal Space Mapping ◽  
Force Microscopy ◽  
Atomic Force ◽  
Out Of Plane

We have presented the structural, surface morphology, magnetic and resistivity data for perovskite LaMnO3 epitaxial thin films which are fabricated on well-oriented (001) LaAlO3 substrates by pulsed laser deposition technique. X-ray diffraction [Formula: see text]–[Formula: see text] linear scans and reciprocal space mapping measurement confirm that the out-of-plane and in-plane epitaxial relationship are LMO(001)/LAO(001) and LMO(110)/LAO(110), respectively. Surface roughness determined by atomic force microscopy was no more than 0.3 nm. In the whole studied temperature range, all films only show a paramagnetic behavior instead of any magnetic phase transitions. Correspondingly, the electron transport behaviors always exhibit an insulting state as the temperature changes from high to low. However, we find that none of theoretical models can individually be used to understand their conductive mechanisms. Further studies indicated that charge carries of high and low temperature region obey adiabatic and nonadiabatic small polaronic hopping mechanisms, respectively. This finding offers new ways of exploiting the abnormal ferromagnetism in LaMnO3 multilayer thin films.

Growth and Characterization of Pb-Based Ferroelectric Oxide Thin Films by Mocvd

1995 ◽  
Vol 401 ◽  
Author(s):  
Masaru Shimizu ◽  
Tadashi Shiosaki
Keyword(s):  
Thin Films ◽  
Memory Device ◽  
Initial Growth ◽  
Epitaxial Relationship ◽  
Pzt Thin Films ◽  
Atomic Force ◽  
Device Applications ◽  
Switching Characteristics ◽  
Plzt Thin Films ◽  
Relationship Of

AbstractUsing the MOCVD process to produce Pb(Zr, Ti)O3 (PZT) thin films, control of the film stoichiometry and crystalline phase was achieved. The PZT films obtained showed good step coverage, 67%. Uniform PZT and PLZT thin films with a variation of film thickness of less than ±1.5% were successfully obtained on a 6–8 inch silicon wafer. For the evaluation of the crystallinity and epitaxial relationship of the PZT thin films, the total reflection X-ray diffraction (TRXD) method was used for the first time. Using TRXD, the in-plane orientations of PZT and Pt in PZT/Pt/MgO were evaluated. The growth mechanism of PbTiO3 and PZT thin films at the initial growth stage was also investigated using an atomic force microscope (AFM). The switching characteristics of PZT capacitors using Ir and IrO2 electrodes for memory device applications were also investigated and a PZT capacitor with no fatigue up to a switching cycle of 1011 was obtained.

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