Effect of Growth Conditions and Buffer Layers on the Metal-Insulator Transition in V2O3 Thin Films

1995 ◽  
Vol 401 ◽  
Author(s):  
H. Schuler ◽  
G. Weissmann ◽  
C. Renner ◽  
S. Six ◽  
S. Klimm ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
Metal Insulator ◽  
X Ray ◽  
Sapphire Substrates ◽  
Hall Effect Measurements ◽  
Mi Transition

AbstractThin films of V2O3 with thickness from 20 to 450 nm were deposited on (0001) oriented sapphire substrates by reactive e-beam evaporation. LEED, x-ray diffraction and AFM studies show highly oriented grains with a lateral size of 50 to 800 nm, dependent on substrate temperature and deposition rate. The films were characterized by optical and infrared transmission, electrical resistance and Hall effect measurements. Films grown directly on the Al2O3-substrate show a very broad metal-insulator (MI) transition as a function of temperature. The width of the transition decreases with increasing film thickness. The insertion of Cr2O3 buffer layers decreases the transition width by a further factor of three. The electronic properties of the films can be drastically influenced by the growth conditions.

IIIB- Nitride Semiconductors for High Temperature Electronic Applications

1999 ◽  
Vol 572 ◽  
Author(s):  
X. Bai ◽  
D. M. Hill ◽  
M. E. Kordesch
Keyword(s):  
Thin Films ◽  
Nitrogen Pressure ◽  
Atomic Nitrogen ◽  
Nitride Semiconductors ◽  
Infrared Transmission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Evaporation ◽  
Hall Effect Measurements ◽  
High Temperature Electronic

ABSTRACTThin films of ScN and YN were grown on silicon, quartz and sapphire using metal evaporation and an RF atomic nitrogen source. YN decomposes on contact with water vapor, and only AlN capped films could be stabilized. ScN is stable in air and water, and thin films of this material deposited at temperatures between 300 and 900 °C show a substrate-dependent film texture. Typical growth rates were ∼ 0.1 nm/second with a 300W N discharge at about 0.1 mTorr Nitrogen pressure. Structural characterization by x-ray diffraction, infrared transmission spectroscopy and Hall effect measurements on n-type ScN and the fabrication of p-n junctions of n- type ScN with silicon are presented.

Epitaxial Growth of Cerium Oxide Buffer Layers on MgO, YSZ and Sapphire Substrates

2000 ◽  
Vol 619 ◽  
Author(s):  
A. Thorley ◽  
S. Gnanarajan ◽  
A. Katsaros ◽  
N. Savvides
Keyword(s):  
Thin Films ◽  
Epitaxial Growth ◽  
Buffer Layers ◽  
Metal Target ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Sapphire Substrates ◽  
Pole Figures ◽  
Biaxial Alignment

ABSTRACTWe studied the epitaxial growth of CeO2 thin films deposited onto MgO(100), YSZ(100) and Al2O3(1102 ) (r-plane sapphire) substrates by reactive dc magnetron sputtering of a Ce metal target in an Ar/O2 plasma. The crystalline quality and biaxial alignment of the films was determined using x-ray diffraction techniques (θ-2θ, ω-scans, pole figures, ø-scans). The CeO2/MgO(100) and CeO2/Al2O3(1102) epitaxy was evident at 600°C and developed to nearly perfect biaxial alignment at 850°C with Δø = 5° and 9° respectively. The CeO2/YSZ (100) epitaxy occurred below 300°C while deposition at ≥ 650°C led to single-crystal quality CeO2 films with Δø = 0.2°.

Non-Polar GaN/AlN Superlattices on A-plane AlN (500nm) Buffer Layers Grown by RF-MBE

2004 ◽  
Vol 831 ◽  
Author(s):  
Takayuki Morita ◽  
Akihiko Kikuchi ◽  
Katsumi Kishino
Keyword(s):  
Molecular Beam ◽  
Growth Conditions ◽  
Buffer Layers ◽  
Structural Quality ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Frequency Plasma ◽  
Diffraction Peaks ◽  
Rich Side

ABSTRACTThe growth conditions of A-plane AlN and GaN epitaxial layers by radio-frequency plasma assisted molecular beam epitaxy on R-plane sapphire substrates were investigated. The growth temperature and V/III supply ratio dependency on structural quality and surface roughness was described. The optimum V/III ratio for A-plane GaN and AlN layers was shifted to nitrogen rich side compared to the C-plane layers. A-plane GaN/AlN superlattices (SLs) were also grown on R-plane sapphire substrates. The X-ray diffraction peaks from a primary and a 1st satellite were observed. From a comparison of low temperature photoluminescence peak wavelength between A-plane and C-plane SLs, the built-in electrostatic field originated from spontaneous and piezoelectric polarization is negligible for A-plane SLs.

Properties of Sputter Deposited ZnO Films Co-doped with Lithium and Phosphorus

2013 ◽  
Vol 1494 ◽  
pp. 77-82
Author(s):  
T. N. Oder ◽  
A. Smith ◽  
M. Freeman ◽  
M. McMaster ◽  
B. Cai ◽  
...  
Keyword(s):  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sapphire Substrates ◽  
Hall Effect Measurements ◽  
Sputter Deposited ◽  
P Type ◽  
Post Deposition ◽  
Co Doped

ABSTRACTThin films of ZnO co-doped with lithium and phosphorus were deposited on sapphire substrates by RF magnetron sputtering. The films were sequentially deposited from ultra pure ZnO and Li3PO4 solid targets. Post deposition annealing was carried using a rapid thermal processor in O2 and N2 at temperatures ranging from 500 °C to 1000 °C for 3 min. Analyses performed using low temperature photoluminescence spectroscopy measurements reveal luminescence peaks at 3.359, 3.306, 3.245 eV for the co-doped samples. The x-ray diffraction 2θ-scans for all the films showed a single peak at about 34.4° with full width at half maximum of about 0.17°. Hall Effect measurements revealed conductivities that change from p-type to n-type over time.

The Use of BaF2 Buffer Layers for the Sputter-Deposition of Ticabacuo Thin-Film Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
K.M. Hubbard ◽  
P.N. Arendt ◽  
D.R. Brown ◽  
D.W. Cooke ◽  
N.E. Elliott ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Sputter Deposition ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Film Substrate ◽  
Ion Backscattering ◽  
Scanning Electron

AbstractThin films of the Tl‐based superconductors often have relatively poor properties because of film/substrate interdiffusion which occurs during the anneal. We have therefore investigated the use of BaF2 as a diffusion barrier. TICaBaCuO thin films were deposited by dc magnetron sputtering onto MgO <100> substrates, both with and without an evaporation‐deposited BaF2 buffer layer, and post‐annealed in a Tl over‐pressure. Electrical properties of the films were determined by four‐point probe analysis, and compositions were measured by ion‐backscattering spectroscopy. Structural analysis was performed by X‐ray diffraction and scanning electron microscopy. The BaF2 buffer layers were found to significantly improve the properties of the TICaBaCuO thin films.

MICROSTRUCTURES OF SPUTTERED ORIENTED Si/CeO2 BILAYERs YBa2Cu3O7-δ/Si INTEGRATED MICROELECTRONICS

2003 ◽  
Vol 17 (04n06) ◽  
pp. 848-854 ◽  
Author(s):  
A. CHIODONI ◽  
E. MEZZETTI ◽  
D. BOTTA ◽  
L. GOZZELINO ◽  
B. MINETTI ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Cerium Dioxide ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Sputtering Deposition ◽  
X Ray ◽  
Integrated Electronics ◽  
Lattice Matching ◽  
Deposition Techniques

In the framework of a research aimed to superconductor/semiconductor integrated electronics, we have grown a-axis oriented YBa 2 Cu 3 O 7-δ (YBCO) thin films on silicon (100) substrates with (111) oriented insulating buffer layers of cerium dioxide ( CeO 2), using magnetron sputtering deposition techniques. The properties of the cerium dioxide layer have been preliminary optimized by means of several layout and by monitoring the growing procedures through X-ray diffraction, AFM and TEM techniques. The lattice matching between CeO 2 and YBCO resulted to be worsened by an amorphous thin SiO 2 layer at the Si/CeO 2 interface, that decouples the buffer orientation from the seed orientation. However, it was possible to grow a relatively thick, optimally textured layer of CeO 2 without spurious orientations. The YBCO films deposited on top of this layer result preferentially a-axis oriented. The transition widths are very large, jet well controllable and reproducible. Some technological applications can be already envisaged.

Thermoelectric Properties of C-Axis-Oriented Ca3Co4O9+δ Films Grown on MgO-Buffered Si (100) by PLD Technique

2010 ◽  
Vol 29-32 ◽  
pp. 1913-1918
Author(s):  
Xia Zhang ◽  
Hong Chen ◽  
Qiu Hui Liao ◽  
Xia Li
Keyword(s):  
Thin Films ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Buffer Layers ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Current State ◽  
Good Crystallinity

High-quality c-axis-oriented Ca3Co4O9+δ thin films have been grown directly on Si (100) wafers with inserting MgO buffer layers by pulsed-laser deposition (PLD). X-ray diffraction and scan electron microscopy show good crystallinity of the Ca3Co4O9+δ films. The resistivity and Seebeck coefficient of the Ca3Co4O9+δ thin films on Si (100) substrates are 9.8 mΩcm and 189 μV/K at the temperature of 500K, respectively, comparable to the single-crystal samples. This advance demonstrates the possibility of integrating the cobaltate-based high thermoelectric materials with the current state-of-the-art silicon technology for thermoelectricity-on-a-chip applications.

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.

Structural, Magnetic and Magneto-tranport Properties of Reactive-sputtered Fe3O4 Thin Films

2010 ◽  
Vol 1250 ◽  
Author(s):  
Xinghua Wang ◽  
Sarjoosing Goolaup ◽  
Peng Ren ◽  
Wen Siang Lew
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Native Oxide ◽  
X Ray Diffraction ◽  
Verwey Transition ◽  
Electrical Measurements ◽  
Metal Insulator ◽  
X Ray ◽  
Sample Measurement

AbstractThin films of magnetite (Fe3O4) are grown on a single-crystal Si/SiO2 (100) substrate with native oxide using DC reactive sputtering technique at room tempreture (RT) and 300C. The x-ray diffraction(XRD) result shows the thermal energy during deposition enhances the crystallization of the Fe3O4 and x-ray photoelectron spectroscopy confirms the film deposited at 300C is single-phase Fe3O4 while the film deposited at RT is mostly ν-Fe2O3. The electrical measurements show that the resistivity of the Fe3O4 film increases exponentially with decreasing temperature, and exhibit a sharp metal-insulator transition at around 100 K, indicating the Verwey transition feature. The saturation magnetization Ms of Fe3O4 film measured by vibrating sample measurement (VSM) at RT was found to be 445 emu/cm3.

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].

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