YBa2Cu3O7 Thin Films on Polycrystalline Diamond Films with Buffer Layers

1992 ◽  
Vol 275 ◽  
Author(s):  
G. Cui ◽  
C. P. Beetz ◽  
B. A. Lincoln ◽  
P. S. Kirlin
Keyword(s):  
Thin Films ◽  
Diamond Films ◽  
Rf Sputtering ◽  
Polycrystalline Diamond ◽  
Fast Response ◽  
Buffer Layers ◽  
Multichip Modules ◽  
Ir Detectors ◽  
Ybco Films ◽  
First Time

ABSTRACTThe deposition of in-situ YBa2CU3O7-δ Superconducting films on polycrystalline diamond thin films has been demonstrated for the first time. Three different composite buffer layer systems have been explored for this purpose: (1) Diamond/Zr/YSZ/YBCO, (2) Diamond/Si3N4/YSZ/YBCO, and (3) Diamond/SiO2/YSZ/YBCO. The Zr was deposited by dc sputtering on the diamond films at 450 to 820 °C. The YSZ was deposited by reactive on-axis rf sputtering at 680 to 750 °C. The Si3N4 and SiO2 were also deposited by on-axis rf sputtering at 400 to 700 °C. YBCO films were grown on the buffer layers by off-axis rf sputtering at substrate temperatures between 690 °C and 750 °C. In all cases, the as-deposited YBCO films were superconducting above 77 K. This demonstration enables the fabrication of low heat capacity, fast response time bolometric IR detectors and paves the way for the use of HTSC on diamond for interconnect layers in multichip modules.

Chemical Solution Deposition of Lanthanum Zirconate Buffer Layers on Biaxially Textured Ni–1.7% Fe–3% W Alloy Substrates for Coated-conductor Fabrication

2002 ◽  
Vol 17 (6) ◽  
pp. 1543-1549 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
T. Aytug ◽  
B. W. Kang ◽  
P. M. Martin ◽  
...  
Keyword(s):  
Sol Gel ◽  
Rf Sputtering ◽  
Cube Texture ◽  
Dip Coating ◽  
Buffer Layers ◽  
Lanthanum Zirconate ◽  
Solution Deposition ◽  
Ybco Films ◽  
Current Densities ◽  
Gel Processing

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni–1.7% Fe–3% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effects of increasing the annealing speed on the texture, microstructure, and carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of yttria-stabilized zirconia and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using pulsed laser deposition. Critical current densities (Jc) of 1.9 MA/cm2 at 77 K and self-field and 0.34 MA/cm2at 77 K and 0.5 T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers and the highest ever obtained using solution seed layers.

Reduced YSZ deposition temperatures for YBa2Cu3Ox/YSZ thin films on sapphire

1995 ◽  
Vol 10 (5) ◽  
pp. 1086-1090 ◽  
Author(s):  
J.H. Kroese ◽  
A.J. Drehrman ◽  
J.A. Horrigan
Keyword(s):  
Thin Films ◽  
Partial Pressure ◽  
Film Surface ◽  
Buffer Layers ◽  
Negative Ion ◽  
Partial Pressure Of Oxygen ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Ybco Films ◽  
X Ray

Thin films of Y-stabilized ZrO2 (YSZ) were deposited by RF diode sputtering on R-plane sapphire as a buffer layer for the deposition of YBa2Cu3O3 (YBCO). By increasing the partial pressure of oxygen in the sputter gas mixture from 20% to 50%, it was found that the substrate temperature required to obtain (100) oriented YSZ deposition could be lowered to 630 °C from 800 °C. This change is attributed to heating or mixing effects at the film surface, due to an increase in negative ion bombardment, which supplements the effects of external heating. Increases in the partial pressure of oxygen beyond 50% were found to be counterproductive. YBCO films, deposited on the YSZ buffer layers via magnetron sputtering, showed c-axis orientation and transition temperatures of 82 K. Orientation of both the YSZ and YBCO films was confirmed by x-ray diffraction and SEM characterization.

Fabrication of High Jc YBa2Cu3O7-δ Coated Conductors Using Sol-Gel Buffer Layers On Nickel and Nickel Alloy Substrates

2001 ◽  
Vol 689 ◽  
Author(s):  
S. Sathyamurthy ◽  
M. Paranthaman ◽  
B. W. Kang ◽  
H. Y. Zhai ◽  
T. Aytug ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Sol Gel ◽  
Rf Sputtering ◽  
Cube Texture ◽  
Dip Coating ◽  
Coated Conductors ◽  
Buffer Layers ◽  
Ybco Films

Sol-gel processing of La2Zr2O7 (LZO) buffer layers on biaxially textured Ni-3 at.% W alloy substrates using a continuous reel-to-reel dip-coating unit has been studied. The epitaxial LZO films obtained have a strong cube texture and uniform microstructure. The effect of increasing the annealing speed on the texture, microstructure and the carbon content retained in the film were studied. On top of the LZO films, epitaxial layers of Yttria Stabilized Zirconia (YSZ) and Ceria (CeO2) were deposited using rf sputtering, and YBa2Cu3Ox (YBCO) films were then deposited using Pulsed Laser Deposition (PLD). A critical current density (Jc) of 1.9 MA/cm2 at 77K and self-field and 0.34 MA/cm2 at 77K and 0.5T have been obtained on these films. These values are comparable to those obtained on YBCO films deposited on all-vacuum deposited buffer layers, and are the highest ever obtained using solution seed layers. The use of all-solution buffers for coated conductor processing has also been explored. A critical current density of 1.1 MA/cm2 at 77 K and self-field was obtained on YBCO films grown be PLD on LZO buffered nickel substrates.

scholarly journals Introducing SiOC as novel dielectric platform for photonic integration

2020 ◽  
Vol 16 (1) ◽  
pp. 81-84
Author(s):  
Faisal Ahmed Memon ◽  
Imran Ali Qureshi ◽  
Abdul Latif Memon ◽  
Erum Saba
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Large Scale ◽  
Rf Sputtering ◽  
Silicon Oxycarbide ◽  
Index Of Refraction ◽  
Photonic Integration ◽  
Index Contrast ◽  
Photonic Waveguides ◽  
First Time

In this paper, we explore the potential of silicon oxycarbide (SiOC) as a novel dielectric platform for integrated photonics and present photonic waveguides. The interesting features of SiOC are its wide tunable window of refractive index and low absorption, that are considered key for large scale photonic integration. It is possible to tune SiOC refractive index from silica glass (1.45) to silicon carbide (3.2) that allows to realize a myriad of photonic passive devices. We have prepared SiOC thin films by employing reactive RF sputtering technique and examined their structural and optical properties using several techniques such as SEM, AFM, ellipsometry, profilometry, and prism coupling. For the first time, SiOC thin films with index of refraction of 1.554 at the standard telecom wavelength 1.55 μm are exploited for the fabrication of photonic waveguides and the propagation losses around 0.37 dB/mm are measured. SiOC photonic waveguides exhibit relatively higher index contrast with silica cladding when compared to traditional Ge-doped silica platform.

Laser Ablation Deposited YBa2Cu3Ox, Thin Films on YSZ/Si(100)

1992 ◽  
Vol 285 ◽  
Author(s):  
F. Sánchez ◽  
M. Varela ◽  
X. Queralt ◽  
R. Aguiar ◽  
J.L. Morenza
Keyword(s):  
Mass Spectrometry ◽  
Thin Films ◽  
Laser Ablation ◽  
Secondary Ion Mass Spectrometry ◽  
Buffer Layers ◽  
Metallic Behavior ◽  
Ybco Films ◽  
Ion Mass Spectrometry ◽  
Zero Resistance ◽  
Secondary Ion

ABSTRACTSuperconducting YBa2Cu3Ox (YBCO) thin films have been deposited on Si(100) substrates with yttria-stabilized zirconia (YSZ) buffer layers by laser ablation. Buffers have been obtained by laser ablation as well. The films have been characterized by scanning electron microscopy, x-ray diffractometry, secondary ion mass spectrometry, and four-contact electrical resistivity measurements. Secondary ion mass spectrometry results indicate very low interdiffusion between Si, YSZ and YBCO. The best YBCO films are textured with c axis perpendicular to the substrate and their resistance shows a normal state metallic behavior with zero resistance at temperatures higher than 80 K. The properties of YBCO films have been related with the substrate temperature and oxygen partial pressure during deposition.

scholarly journals Fabrication of YBa2Cu3Oy Thin Films on Textured Buffer Layers grown by Plasma Beam Assisted Deposition

1997 ◽  
Vol 50 (2) ◽  
pp. 381 ◽  
Author(s):  
M. Fukutomi ◽  
S. Kumagai ◽  
H. Maeda
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Large Scale ◽  
Buffer Layers ◽  
Weak Links ◽  
Large Area ◽  
Ybco Films ◽  
Metallic Substrates ◽  
Plasma Beam ◽  
A New Technique

A new technique named plasma beam assisted deposition (PBAD) is proposed to grow in-plane textured yttria-stabilised zirconia (YSZ) thin films on polycrystalline metallic substrates as a buffer layer for deposition of YBa2Cu3Oy (YBCO) films. The in-plane texturing of the YBCO films obtained is decisively governed by that of the YSZ buffer layer on which the YBCO grows. Because of a reduction of the weak links at high-angle grain boundaries, a marked increase in the critical current density Jc is observed with improved texturing of the YBCO films. So far, it has been demonstrated that YBCO films with Jc above 105 A cm-2 (77 K, 0 T) can be successfully deposited by a laser ablation technique. The PBAD process proposed here is found to be valuable technologically because it offers a very convenient method to grow textured films on long tape or large area substrates. An attempt was also made to grow textured films simultaneously on one side or both sides of various pieces of tape substrates. The results indicate that PBAD is one potential technique for future large scale application of YBCO films.

scholarly journals A Simple and Efficient Visible Light Photodetector based on Co3O4/ZnO Composite

2021 ◽  
Author(s):  
Aneela Tahira ◽  
Raffaello Mazzaro ◽  
Federica Rigoni ◽  
Ayman Nafady ◽  
Shoyebmohamad F Shaikh ◽  
...  
Keyword(s):  
Visible Light ◽  
Zno Nanorods ◽  
Fast Response ◽  
Buffer Layers ◽  
Cubic Phases ◽  
Light Absorber ◽  
Aqueous Chemical Growth ◽  
Growth Method ◽  
P Type ◽  
First Time

Abstract Herein, we propose for the first time visible light photodetector based on n-type ZnO nanorods decorated with p-type Co3O4 nanowires. The heterojunction was fabricated on fluorine doped tin oxide (FTO) glass substrate by low temperature aqueous chemical growth method. ZnO exhibits nanorod morphology and cobalt oxide possesses nanowire shape with sharp tail. Energy dispersive spectroscopy (EDS) confirmed the presence of Zn, O, and Co elements in the heterojunction. ZnO and Co3O4 have hexagonal and cubic phases, respectively, as confirmed by XRD. The dense and perpendicular ZnO nanorods are acting as a scattering layer for visible light, while Co3O4 nanowires act as a visible-light absorber. The all oxide p-n junction can operate as visible light photodetector. Furthermore, the heterojunction also shows a reproducible and fast response for the detection of visible light. Optimization of the device is needed (presence of buffer layers, tuning a thickness of the optical absorber) to improve its functionalities.

Effects of Post-Deposition Processing on the Ultimate Grain Size in Metastable Semiconductor Thin Films to be Used in IR Detectors

1994 ◽  
Vol 343 ◽  
Author(s):  
Susanne M Lee
Keyword(s):  
Thin Films ◽  
Thick Films ◽  
Rf Sputtering ◽  
Solubility Limit ◽  
Nucleation And Growth ◽  
Separation Mechanism ◽  
Post Deposition Annealing ◽  
Ir Detectors ◽  
Solid Solubility Limit ◽  
Post Deposition

ABSTRACTThrough post-deposition annealing in a differential scanning calorimeter (DSC), we have manufactured both thin (200 nm) and bulk (8000 nm) single phase films of crystalline Ge1–xSnx, using rf sputtering. The Sn concentrations produced ranged up to 31 at.%, well beyond the solid solubility limit of this system. There was a marked difference, in the asdeposited structure, between thick and thin films produced under the same deposition conditions. Quantitative models for both systems are given in this paper and were deduced frorn DSC measurements in conjunction with electron microscopy. The metastable crystalline state in the thin films formed by nucleation and growth from an amorphous phase; whereas in the thick films, the desired phase was already present in the as-deposited films and only growth of preexisting grains was observed upon post-deposition annealing. When annealed to high temperature, the Sn phase separates from the alloys and we postulate here that it does so by nucleation and growth of β-Sn. With this hypothesis, the Sn separation in the 8000 nm thick films was accurately modeled by a two-mechanism process, however, in the 200 nm thick films, only one phase separation mechanism was necessary to accurately fit the data. Both models were corroborated by the subsequent melting behavior of the phase separated Sn which, though it varied depending on the sample being measured, always exhibited a melting endotherm starting 25–35°C lower than the bulk melting temperature of Sn. Speculation on the reasons for this are presented.

Formation of Single-crystal CoSi2 Buffer Layers on Si(100) Substrates by High Dose Co Ion Implantation for the Deposition of YBa2Cu3O7−x Thin Films

1997 ◽  
Vol 12 (8) ◽  
pp. 2072-2080 ◽  
Author(s):  
Yijie Li ◽  
P. Seidel ◽  
F. Machalett ◽  
S. Linzen ◽  
F. Schmidl
Keyword(s):  
Thin Films ◽  
Ion Implantation ◽  
Single Crystal ◽  
Ybco Film ◽  
Rutherford Backscattering Spectrometry ◽  
Multilayered Structure ◽  
Buffer Layers ◽  
High Dose ◽  
Ybco Films ◽  
Minimum Yield

High quality single-crystal CoSi2 layers have been successfully formed on Si(100) using low energy high dose Co ion implantation followed by subsequent annealing method as a buffer layer for the deposition of YBa2Cu3O7−x (YBCO) thin films. Rutherford backscattering spectrometry with channeling (RBS-C) measurements showed that CoSi2 layers after annealing at temperatures between 850 and 950 °C had a minimum yield Xmin of about 3%. X-ray diffraction (XRD) spectra revealed that CoSi2 layers had the same orientation as the Si(100) substrates. Phi scan XRD spectra proved that CoSi2 layers epitaxially grew in the cube-on-cube epitaxial growth mode with respect to the Si(100) substrates. YBCO films and CeO2/YSZ buffer layers were deposited on CoSi2/Si(100) substrates via laser ablation and electron beam evaporation, respectively. θ-2θ, ω, and φ scan XRD spectra illustrated that YBCO films and CeO2/YSZ buffer layers had the epitaxial structure both in a-b plane and along the c-axis. YBCO films grown on this multilayered structure demonstrated excellent superconducting properties with the zero resistance transition temperature Tc0 of 87–90 K. The transition width (ΔTc) was about 1 K. Orientation and epitaxial crystalline quality of YBCO films and CeO2/YSZ buffer layers were confirmed by XRD and RBS-C characterization. All films consisted of c-axis oriented grains. RBS-C spectra indicated a high degree of crystalline perfection with a channeling minimum yield for Ba as low as 8%, and interdiffusion between the YBCO film and buffer layers or between the YBCO film and the substrate was limited. This multilayer system shows the possibility for the application of YBa2Cu3O7−x thin films on technical Si substrates in the field of hybrid superconductor-semiconductor technology.

Preparation of Yba2Cu3O7-X. Superconducting Thin Films by Means of Single Target Rf-Sputtering+

1989 ◽  
Vol 169 ◽  
Author(s):  
Herman D.L. Weyten ◽  
R. De Batist ◽  
P. Nagels ◽  
J. Cornelis
Keyword(s):  
Thin Films ◽  
Rf Sputtering ◽  
Buffer Layers ◽  
Superconducting Thin Films ◽  
High Tc ◽  
Resistivity Measurements ◽  
Single Target ◽  
Deposited Films ◽  
Post Deposition

AbstractHigh Tc superconducting thin films have been deposited on sapphire by means of RF‐sputtering from a single stoichiometric target of YBa2Cu3O7‐x composition. The YBa2Cu3O7‐x films were deposited in an argon‐oxygen atmosphere on a substrate which reached a temperature of s 400°C during deposition. The study of stoichiometry and homogeneity of the as‐deposited films, by means of electromicroprobe analysis (EMPA), was used to optimize the sputtering parameters of the system. To achieve superconductivity, with an onset of s 90 K, a high‐temperature, post‐deposition thermal treatment in oxygen was necessary. Resistivity measurements show that, with respect to the bulk samples, zero resistivity is lowered as a result of substrate interaction. The use of buffer layers can improve the quality of the superconducting thin films.

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