Surface Structure and Transport Properties of YBa2Cu3O7-δ Using La2/3Ca1/3MnO3 as Buffer

2003 ◽  
Vol 10 (02n03) ◽  
pp. 317-323 ◽  
Author(s):  
W. S. Tan ◽  
L. Yang ◽  
H. Sha ◽  
X. S. Wu ◽  
J. Gao ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Ultrathin Films ◽  
Rf Magnetron Sputtering ◽  
Epitaxial Films ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Out Of Plane

The YBa2Cu3O7-δ (YBCO) ultrathin films were prepared by off-axis rf magnetron sputtering on SrTiO3 (STO) substrate with a 300-Å-thick La2/3Ca1/3MnO3 (LCMO) buffer layer. At low temperature, the magnetism of the LCMO buffer layer seemed to be screened by the epitaxial YBCO layer with a thickness of more than about 125 Å. A remarkable magnetoresistance (MR) ratio was obtained for thinner YBCO cap layer. The superconducting transition temperature, Tc, decreases with decreasing YBCO thickness and disappears at the thickness of less than 85 Å. X-ray diffraction (XRD) was used to characterize the quality of the buffer and epitaxial films. The out-of-plane lattice parameters for both buffer and epitaxial layer varied monotonically. The surface structures of the buffer and the epitaxial YBCO films were characterized by atomic force microscopy (AFM). Interfacial diffusions for cations such as Y, Cu, La, Ca and Sr were deduced from Auger electron spectroscopy (AES). The larger diffusion length was found at the interface between YBCO and LCMO, which may relate to the suppression of superconductivity and magnetoresistance.

PEMBE-Growth of Gallium Nitride on (0001) Sapphire: A comparison to MOCVD grown GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
H. Angerer ◽  
O. Ambacher ◽  
R. Dimitrov ◽  
Th. Metzger ◽  
W. Rieger ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metalorganic Chemical Vapour Deposition

Thin films of GaN on c-plane sapphire were grown by plasma-enhanced molecular beam epitaxy (PEMBE). The influence of different growth conditions on the quality of the epitaxial layers was studied by x-ray diffraction (XRD), atomic force microscopy (AFM) and Hall measurements. For low deposition temperatures, the growth of a thin buffer layer of AlN results in a decrease of the XRD rocking curve full width at half maximum (FWHM) but also in poorer quality in electronic and optical properties. Samples of 3μm thickness with 570 arcsec FWHM in the XRD rocking curve, a near band gap PL-emission FWHM at 5 K of 7 meV, charge carrier densities of ne = 2 × 1017 cm−3, and Hall mobilities of 270 cm2/Vs at 300 K were grown without a buffer layer. A comparison of the morphology and XRD rocking curves with those of GaN films deposited by metalorganic chemical vapour deposition (MOCVD) shows that the two methods have different growth mechanisms.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

Lateral Size of Self-Patterned Nanostructures Controlled by Multi-Step Deposition

2005 ◽  
Vol 106 ◽  
pp. 117-122 ◽  
Author(s):  
Izabela Szafraniak ◽  
Dietrich Hesse ◽  
Marin Alexe
Keyword(s):  
Electron Microscopy ◽  
Ultrathin Films ◽  
Lateral Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Non Volatile Memory ◽  
Ferroelectric Capacitors ◽  
Scanning Electron

Self-patterning presents an appealing alternative to lithography for the production of arrays of nanoscale ferroelectric capacitors for use in high density non-volatile memory devices. Recently a self-patterning method, based on the use of the instability of ultrathin films during hightemperature treatments, was used to fabricate nanosized ferroelectrics. This paper reports the use of the method for the preparation of PZT nanoislands on different single crystalline substrates - SrTiO3, MgO and LaAlO3. Moreover, a multi-step deposition procedure in order to control lateral the dimension of the crystals was introduced. The nanostructures obtained were studied by atomic force microscopy, scanning electron microscopy and X-ray diffraction.

Studies of Hydroxyapatite Thin Coating Produced by Dual RF Magnetron Sputtering for Biomedical Applications

2011 ◽  
Vol 493-494 ◽  
pp. 473-476
Author(s):  
E.O. Lopez ◽  
F.F. Borghi ◽  
Alexandre Mello ◽  
J. Gomes ◽  
Antonella M. Rossi
Keyword(s):  
Magnetron Sputtering ◽  
Deposition Time ◽  
Grazing Incidence ◽  
Rf Magnetron Sputtering ◽  
Nanocrystalline Phase ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sputtering Power

In this present work, we characterize HAp thin films deposited by dual magnetron sputtering device DMS on silicon (Si/HAp). The sputtering RF power was varied from 90 watts to 120 watts and deposition times from 60 to 180 minutes. The argon and oxygen pressure were fixed at 5.0 mTorr and 1.0 mTorr, respectively. Grazing incidence X-ray diffraction (GIXRD) from synchrotron radiation, infrared spectroscopy (FTIR) and atomic force microscopy (AFM) were used for the structural characterization. At lower deposition times, a crystalline phase with preferential orientation along apatite (002) and a disordered nanocrystalline phase were identified. The coating crystallinity was improved with the increase of the deposition time besides the sputtering power.

Reactive Sputtering Growth and Characterizations of InN Thin Films on Si Substrates

2012 ◽  
Vol 545 ◽  
pp. 290-293
Author(s):  
Maryam Amirhoseiny ◽  
Hassan Zainuriah ◽  
Ng Shashiong ◽  
Mohd Anas Ahmad
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Rf Magnetron Sputtering ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force

We have studied the effects of deposition conditions on the crystal structure of InN films deposited on Si substrate. InN thin films have been deposited on Si(100) substrates by reactive radio frequency (RF) magnetron sputtering method with pure In target at room temperature. The nitrogen gas pressure, applied RF power and the distance between target and substrate were 2×10-2 Torr, 60 W and 8 cm, respectively. The effects of the Ar–N2 sputtering gas mixture on the structural properties of the films were investigated by using scanning electron microscope, energy-dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction techniques.

Growth of GaN epilayers on Si(111) substrates using multiple buffer layers

2001 ◽  
Vol 693 ◽  
Author(s):  
P.R. Hageman ◽  
S. Haffouz ◽  
A. Grzegorczk ◽  
V. Kirilyuk ◽  
P.K. Larsen
Keyword(s):  
Atomic Force Microscopy ◽  
Epitaxial Films ◽  
Buffer Layers ◽  
High Quality ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Vapor Deposition Technique

AbstractWe present a study of the growth of high quality GaN films on Si(111) substrates by MetalOrganic Chemical Vapor Deposition technique. In order to improve the quality of the epitaxial films we introduced different nucleation or buffer layers and combinations of them. Our results obtained on an optimized AlN nucleation layer will serve as reference point. In order to improve the quality of the epitaxial films we introduced different combinations of nucleation and intermediate layers. The first combination consists of an optimized AlN nucleation layer followed by a 1 m-thick GaN film, on which we deposited SixNy/GaN intermediate layers. Based on the optimized AlN nucleation layer, we introduced AlGaN/GaN superlattices or AlN intermediate buffer layers. Additionally, we present results on the modification the Si(111) surface with NH3 to promote nucleation from selective GaN islands. In all experiments the total thickness of the GaN epilayers was 3 m m. X-ray diffraction, photoluminescence, Hall measurements and atomic force microscopy were used in order to elucidate the effectiveness of these growth processes. For the most successful deposition scheme, the one with the SixNy/GaN intermediate layers, the resulting GaN layers are of high quality as compared to the other methods. The donor bound exciton, which dominates the photoluminescence spectrum, showed a full width at half maximum (FWHM) of about 50 meV at room temperature and 10 meV at 4K. The FWHM of the symmetric (0002) rocking curves in w-scan is about 640 arcsec. The root-mean-square roughness, as measured by atomic force microscopy, does not exceed 10 Å.

Growth of (0001) ZnO Thin Films on Sapphire

1996 ◽  
Vol 449 ◽  
Author(s):  
A. J. Drehman ◽  
P. W. Yip
Keyword(s):  
Surface Roughness ◽  
Buffer Layers ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Force Microscopy ◽  
Sapphire Substrates ◽  
Atomic Force

ABSTRACTUsing reactive rf sputtering, we have grown (0001) oriented ZnO films in situ on heated c-axis sapphire substrates, that are promising, particularly in terms of surface roughness, as buffer layers for the subsequent epitaxial growth of III-V nitride films. We compare the effects of on-axis and off-axis sputter geometries on the film epitaxy and smoothness. We also examined the effect of substrate temperature on the growth and smoothness and quality of the film. X-ray diffraction was used to verify the hexagonal ZnO phase, its c-axis orientation and, qualitatively, the degree of its epitaxy. Atomic Force Microscopy (AFM) was used to determine the ZnO growth morphology and roughness. Our best films, obtained by off-axis sputter deposition, have a surface roughness of less than 1 nm.

GROWTH OF SPUTTERED-ALUMINUM OXIDE THIN FILMS ON Si (100) AND Si (111) SUBSTRATES WITH Al2O3 BUFFER LAYER

2016 ◽  
Vol 23 (03) ◽  
pp. 1650016
Author(s):  
WEI QIANG LIM ◽  
SUBRAMANI SHANMUGAN ◽  
MUTHARASU DEVARAJAN
Keyword(s):  
Thin Films ◽  
Aluminum Oxide ◽  
Buffer Layer ◽  
Annealing Temperature ◽  
Rf Magnetron Sputtering ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Atomic Force ◽  
Section Analysis

Aluminum oxide (Al2O3) thin films with Al2O3 buffer layer were deposited on Si (100) and Si (111) substrates using RF magnetron sputtering of Al2O3 target in Ar atmosphere. The synthesized films were then annealed at the temperature of 400[Formula: see text]C, 600[Formula: see text]C and 800[Formula: see text]C in nitrogen (N2) environment for 6[Formula: see text]h. Structural properties and surface morphology are examined by using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Atomic Force Microscope (AFM). XRD analysis indicated that different orientation of Al2O3 were formed with different intensities due to increase in the annealing temperature. From FESEM cross-section analysis results, it is observed that the thickness of films were increased as the annealing temperature increased. EDX analysis shows that the concentration of aluminum and oxygen on both the Si substrates increased with the increase in annealing temperature. The surface roughness of the films were found to be decreased first when the annealing temperature is increased to 400[Formula: see text]C, yet the roughness increased when the annealing temperature is further increased to 800[Formula: see text]C.

Electrochemical Behavior of LiFePO4 Thin Film Prepared by RF Magnetron Sputtering in Li2SO4 Aqueous Electrolyte

2015 ◽  
Vol 14 (01n02) ◽  
pp. 1460027 ◽  
Author(s):  
Jiaxiong Wu ◽  
Wei Cai ◽  
Guangyi Shang
Keyword(s):  
Thin Film ◽  
Magnetron Sputtering ◽  
Rf Magnetron Sputtering ◽  
Ion Diffusion ◽  
X Ray Diffraction ◽  
Electrochemical Tests ◽  
Force Microscopy ◽  
Atomic Force ◽  
Li Ion ◽  
Deposited Film

LiFePO 4 films were deposited on Au / Si substrate by radio-frequency magnetron sputtering. The effect of annealing on the crystallization and morphology of LiFePO 4 thin film has been investigated. X-ray diffraction revealed that the films through annealing were well crystallized compared with as-deposited films. The surface morphology of the thin film was also observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Electrochemical tests in 1M Li 2 SO 4 showed that the annealed thin film in 500°C exhibits larger Li -ion diffusion coefficient (3.46 × 10-7 cm2s-1) than as-deposited film and powder. Furthermore, cyclic voltammetry demonstrate a well-defined lithium intercalation/deintercalation reaction at around 0.45 V versus SCE (i.e., 3.6 V versus Li +/ Li ), suggesting that the annealed LiFePO 4 thin film is a promising candidate cathode film for lithium microbatteries.

Influence of Fe on the Morphology of Spinel in the System MgO-Al2O3-Fe2O3.

2000 ◽  
Vol 654 ◽  
Author(s):  
O.V. Kharissova ◽  
U. Ortiz ◽  
M. Hinojosa
Keyword(s):  
Epitaxial Films ◽  
Catalytic Reactions ◽  
General Interest ◽  
X Ray Diffraction ◽  
Contact Mode ◽  
Surface Conditions ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Conventional Furnace

AbstractThe investigation of the morphology of crystalline solids surfaces is of practical and general interest because many processes such as the growth of epitaxial films, catalytic reactions and others, are intimately connected with surface conditions. In this work we study the surface morphology and structure of the spinel as produced in the system MgO- Al2O3-Fe2O3 at 1400°C for 15 h in a conventional furnace and in a microwave oven for 30 min. The spinel was analyzed by X-ray diffraction, scanning electron microscopy (SEM), X-ray spectrometry (EDX), and atomic force microscopy (AFM). The AFM images were recorded in the contact mode. Images scanned at different magnifications show steps and flat terraces. Experimental observations were made on the nature and distribution of the observed polygonal morphology.

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