Ferroelectric (Pb,La)TiO3 Thin Films Prepared by Metalorganic Chemical Deposition

1994 ◽  
Vol 361 ◽  
Author(s):  
Z. C. ◽  
B.S. Kwak ◽  
A. Erbil
Keyword(s):  
Thin Films ◽  
Quartz Substrate ◽  
Chemical Deposition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Modes ◽  
Quartz Substrates ◽  
Physical Phenomena ◽  
Mocvd Technique ◽  
Metalorganic Chemical

ABSTRACTRecently, we reported results of an investigation of the preparation of highly textured (Pb1−xLax)TiO3 (PLT) thin films grown on Si(100) by metalorganic chemical deposition (MOCVD) [1]. In this paper, we discuss an extension of this work to the growth of PLT thin films on fused quartz substrates by the MOCVD technique. A series of PLT films with x between 0 and 0.32 were prepared. Characterization by x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS) and Raman scattering has been performed on these ferroelectric thin films. XRD indicated the polycrystalline nature of the PLT films and the variation of their tetragonality. The film thickness and La composition were determined by RBS. Raman spectra, measured at 300 and 80 K, showed features of the PLT film and quartz substrate. By using a “difference Raman” technique, more PLT modes were shown. The variations of the PLT Raman modes with the La composition and the measurement temperature were studied. Related physical phenomena and problems are discussed.

Ferroelectric Thin Films of Bismuth Titanate Prepared by Mocvd

1991 ◽  
Vol 243 ◽  
Author(s):  
H. Wang ◽  
L. W. Fu ◽  
S. X. Shang ◽  
S. Q. Yu ◽  
X. L. Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Bismuth Titanate ◽  
Growth Parameters ◽  
Chemical Vapor ◽  
Dispersion Analysis ◽  
Ferroelectric Thin Films ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mocvd Technique

AbstractThe ferroelectric thin films of bismuth titanate (Bi4Ti3O12) have been prepared by metalorganic chemical vapor deposition ( MOCVD) technique at atmosphere. The triphenyl bismuth (Bi(CaH5 ) 3)and tetrabutyl titanate (C16H36O4Ti) were used as precursors. Dense Bi4Ti3 O12 films with smooth shinning surface have been grown on Si( 100) substrates at 550°C whithout postannealing. The as- grown films were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersion analysis ( EDAX). The films showed well-ordered crystallinity with an (001)preffered orientation. The influence of growth parameters on deposition rate, composition and morphology of as-grown films was also discussed.

Improvements of Structural and Optical Properties of GaN/Al0.10Ga0.9N Multi-Quantum Wells by Isoelectronic In-doping

2001 ◽  
Vol 693 ◽  
Author(s):  
Lianshan Wang ◽  
Soo Jin Chua ◽  
Wenhong Sun
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Chemical Deposition ◽  
Crystal Quality ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Flow Rates ◽  
X Ray ◽  
In Doping ◽  
Metalorganic Chemical

Absratct:The effects of isoelectronic In-doping were studied on the structural and optical properties of 3-periods and 10-periods of GaN/Al0.10Ga0.90N multi quantum wells (MQWs). The GaN/Al40.10Ga0.90N MQWs were grown on u-GaN/sapphire via metalorganic chemical deposition (MOCVD) at 1050°C in H2 carrier gas. X-ray diffraction (XRD), and micro-Photoluminescence (PL) measurements revealed that In-doping into well layers improves the crystalline and optical properties of MQWs relative to those samples without In-doping. With increasing Trimethylindium (TMIn) flow rates from 4.2 mol/min to 42.6 mol/min, PL peaks from well layers obviously redshifted, due to the improvement of the strain along the interfaces between MQWS, irrespective of 3-periods or 10 periods MQWs. The improvement of the crystal quality was also confirmed by XRD.

PREFERENTIAL ORIENTATION GROWTH OF AlN THIN FILMS ON Si(111) SUBSTRATES BY PLASMA-ASSISTED MOLECULAR BEAM EPITAXY

2009 ◽  
Vol 16 (06) ◽  
pp. 925-928 ◽  
Author(s):  
L. S. CHUAH ◽  
Z. HASSAN ◽  
H. ABU HASSAN
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Raman Modes ◽  
Orientation Growth ◽  
Good Agreement

This article reports the use of plasma-assisted molecular beam epitaxy (MBE) to grow AlN on Si (111) substrate at 850°C under UHV conditions for 15, 30, and 45 min. The films were characterized by high-resolution X-ray diffraction (HR-XRD) and micro-Raman spectroscopy. XRD measurement revealed that the AlN was epitaxially grown on Si (111). Micro-Raman result showed that all the allowed Raman modes of AlN and Si were clearly visible. Fourier transform infrared (FTIR) spectroscopy has been used to investigate the A1 (LO) and E1 (TO) modes with frequencies (890–899) cm-1 and (668–688) cm-1, respectively. The results are in good agreement with reported phonon frequencies of AlN grown on Si (111).

Ferroelectric memory in La substituted Bi4Ti3O12 thin films

2003 ◽  
Vol 784 ◽  
Author(s):  
R. E. Melgarejo ◽  
M. S. Tomar
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Sol Gel ◽  
Low Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Modes ◽  
La Substitution ◽  
Ferroelectric Memory ◽  
Recent Demonstration

ABSTRACTThe recent demonstration of large ferroelectric memory in rare earth substituted Bi4Ti3O12 attracted a lot of research interest in this material. Bi4-xLaxTi3O12 was synthesized by sol-gel route for different compositions: x = 0.00, 0.46, 0.56, 0.75, 0.95 and thin films were deposited by spin coating on Pt (Pt/TiO2/SiO2/Si) substrate. The post annealed films at 700°C were studied for their structural studies using x-ray diffraction and Raman spectroscopy. The prominent effect of La substitution is observed in low frequency Raman modes. X-ray diffraction and Raman studies show that the film growth was c-axis suppressed. Using improved contacts to Pt substrate, ferroelectric polarization Pr = 51 μC/cm2 has been achieved for 0.63 μm thick film of composition: x = 0.56 (BLT56) without appreciable fatigue.

A Multi-Technique Analysis of MOCVD- Grown Lead Lanthanum Titanate (Pb1−xLax)TiO3 Thin Films on Quartz Substrates

1997 ◽  
Vol 493 ◽  
Author(s):  
H. Y. Chen ◽  
J. Lin ◽  
K. L. Tan ◽  
Z. C. Feng ◽  
B. S. Kwak ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Gradual Change ◽  
X Ray Diffraction ◽  
Raman Scattering Spectroscopy ◽  
X Ray ◽  
Lanthanum Titanate ◽  
Diffuse Reflectance Infrared ◽  
Quartz Substrates

AbstractA series of Lead lanthanum titanate (Pb1−xLax)TiO3 thin films with different compositions of x = 0 − 0.33 have been grown on fused quartz substrates by metalorganic chemical vapor deposition (MOCVD) and analyzed by a variety of techniques including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman scattering spectroscopy (RSS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) techniques. XPS results confirmed the film composition of (Pb1−x Lax)TiO3 and lanthanum enrichment in top surface layers. XRD indicates a preferred (100) orientation for the films with x values of 0.05–0.17, while the films with x values above 0.32 have randomly distributed orientations. A gradual change in the crystal structure from tetragonal to cubic arrangement with increasing La composition is noted. XPS data also show the variation of Ti-O, Pb-0 and La-0 bonding with the change in the La composition. The stretching vibrations corresponding to these oxygen related bonding are observed by DRIFT at 667, 826, 936 and 529 cm−1 respectively. This combined investigation on epitaxial PLT films may enhance our understanding of the ferroelectric PLT materials.

Growth of (001)-Oriented Sbn Thin Films by Solid Source MOCVD

1993 ◽  
Vol 335 ◽  
Author(s):  
Z. Lu ◽  
R. S. Feigelson ◽  
R. K. Route ◽  
R. Hiskes ◽  
S. A. Dicarolis
Keyword(s):  
Thin Films ◽  
Cooling Rate ◽  
Single Phase ◽  
Refractive Indices ◽  
X Ray Diffraction ◽  
X Ray ◽  
Volume Fractions ◽  
Grain Orientations ◽  
Optical Waveguiding ◽  
Mocvd Technique

AbstractBy the solid source MOCVD technique, we have deposited 2000 – 3000 Å thick single phase SrxBa1−xNb2O6 (SBN) films on (100) MgO substrates using tetramethylheptanedionate (thd) sources. X-ray diffraction (XRD) 2θ scans indicated that these films were completely (001) oriented. XRD Φ scans, however, showed the films contained four in-plane grain orientations whose volume fractions could be controlled by altering the Sr/(Sr+Ba) and Nb/(Sr+Ba) ratios in the source powders. The in-plane volume fractions did not change with the deposition rate or the cooling rate. Films with composition Sr0 58Ba0.42Nb1.94O6 had mainly two in-plane orientations. Optical waveguiding behavior was demonstrated in these films. Refractive indices were found to be no= 2.20 and ne = 2.13, as compared to no = 2.31 and ne = 2.27 for bulk SBN60.

Effect of Substrate Variation on Electrical and Magnetic Properties of Mn Doped ZnO of Dilute Magnetic Semiconductors

2005 ◽  
Vol 891 ◽  
Author(s):  
Srikanth Manchiraju ◽  
Govind Mundada ◽  
Ted Kehl ◽  
Craig Vera ◽  
Rishi Patel ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Single Crystal ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Quartz Substrates ◽  
Mn Doped

ABSTRACTIn this paper, the effect of substrate on the domain structure growth and electrical and magnetic properties of epitaxial Mn-doped Zn0.8Mn0.15O (ZnMnO) thin films has been investigated. Epitaxial thin films of ZnMnO dilute magnetic semiconductors (DMS) were grown on various substrates such as single crystal sapphire, single crystal silicon, and quartz substrates using Pulsed Laser Deposition (PLD) technique . Structural, surface, magnetic, and optical properties have been observed on these films using X-Ray diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), and Raman spectroscopy. X-Ray Diffraction shows that films are highly epitaxial and c-axis oriented with some induced strain. AFM images show that film surface is smooth with RMS roughness of the order of 1-2 nm over 5*5sq.micron. Magnetic characteristic properties such as carrier concentration, mobility, and temperature dependent resistivity were also investigated. Carrier concentration decreases and mobility increases for both the films on silicon and quartz substrates when compared to film on sapphire.

Mechanism of Blue Shift of Optical Band Gap in Aluminum-Doped ZnO Thin Films with Blend Bond

2011 ◽  
Vol 685 ◽  
pp. 98-104
Author(s):  
Ling Shen ◽  
Cheng Shen ◽  
Jie Yang ◽  
Fei Xu ◽  
Zhong Quan Ma
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Band Gap ◽  
Optical Band Gap ◽  
Quartz Substrate ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Force ◽  
Nano Crystalline

In this paper, aluminum–doped nano-crystalline zinc oxide (ZnO:Al or AZO) thin films were deposited on fused quartz substrate by pulsed laser ablation at various temperatures. The physical phase and surface morphology were characterized by using X-ray diffraction (XRD) and atomic force microscope (AFM), respectively. The variation of the optical band gap (Egopt) of the films with the temperature was measured through transmittance in UV-VIS wavelength. The results showed that there was a blue shift of Egoptfrom 3.44 eV to 3.62 eV as the growing temperature decreased from 500°C to 200°C. The value of Egoptimmediately recurred from 3.30 to 3.35 eV after a thermal annealing of the samples at 700 °C, inclining to a normal value of bulk zinc oxide. The analyses of XRD and AFM testified that the presence of amorphous phase in the AZO films was the main reason for the blue shift of the optical band gap Egopt.

Comparative study of magneto-transport and lattice-vibrational properties of La2/3Ca1/3MnO3 thin films grown on SrTiO3 and LaAlO3 substrates

2018 ◽  
Vol 32 (26) ◽  
pp. 1850287
Author(s):  
Qiyun Xie ◽  
Xuran Zhou ◽  
Chao Qi ◽  
Gang Bai ◽  
Limin Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Strain State ◽  
Vibration Mode ◽  
Vibrational Mode ◽  
Compressive Strain ◽  
X Ray Diffraction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
X Ray ◽  
Raman Modes

Epitaxial La[Formula: see text]Ca[Formula: see text]MnO3 (LCMO) thin films of 60 nm are deposited on (001)-oriented SrTiO3 (STO) and LaAlO3 (LAO) substrate by modified off-axis magnetron sputtering method. The strain state of the films have been studied by high resolution X-ray diffraction. The magneto-transport properties were found to be strongly dependent on the substrate used. Compared with LCMO/LAO film (compressive strain), LCMO/STO film with tensile strain exhibits lower metal-insulator transition temperature, suppressed Curie temperature, higher resistivity and more localization of electron. The evolution of the Raman modes has also been investigated. The vibrational mode of LCMO/LAO is comparable to the bulk, while the signature of vibration mode at about 610 cm[Formula: see text] induced by strain-related distortion has been observed only in tensile strained LCMO/STO case. The controversial 660 cm[Formula: see text] peak is not observed in our films, which precludes the possible existence of Mn3O4 precipitates in the films.

TEM studies of solid-state reactions in sputter-deposited Nb/Al multilayer thin films

1996 ◽  
Vol 54 ◽  
pp. 1020-1021
Author(s):  
F. Ma ◽  
S. Vivekanand ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Stoichiometric Composition ◽  
Analytical Electron Microscopy ◽  
Grain Structure ◽  
Solid State Reactions ◽  
Multilayer Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sputter Deposited

Solid state reactions in sputter-deposited Nb/Al multilayer thin films have been studied by transmission and analytical electron microscopy (TEM/AEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The Nb/Al multilayer thin films for TEM studies were sputter-deposited on (1102)sapphire substrates. The periodicity of the films is in the range 10-500 nm. The overall composition of the films are 1/3, 2/1, and 3/1 Nb/Al, corresponding to the stoichiometric composition of the three intermetallic phases in this system.Figure 1 is a TEM micrograph of an as-deposited film with periodicity A = dA1 + dNb = 72 nm, where d's are layer thicknesses. The polycrystalline nature of the Al and Nb layers with their columnar grain structure is evident in the figure. Both Nb and Al layers exhibit crystallographic texture, with the electron diffraction pattern for this film showing stronger diffraction spots in the direction normal to the multilayer. The X-ray diffraction patterns of all films are dominated by the Al(l 11) and Nb(l 10) peaks and show a merging of these two peaks with decreasing periodicity.

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