THE INFLUENCE OF SPUTTERING TIME AND OXYGEN PARTIAL PRESSURE ON ELECTRICAL RESISTIVITY OF Bi:2201 THIN FILMS

2004 ◽  
Vol 18 (14) ◽  
pp. 2085-2090 ◽  
Author(s):  
AUREL POP ◽  
GHEORGHE ILONCA ◽  
ROBERT DELTOUR
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Partial Pressure ◽  
Superconducting State ◽  
Electrical Resistance ◽  
Theoretical Models ◽  
Superconducting Transition ◽  
Partial Pressure Of Oxygen ◽  
Optimal Doping ◽  
Synthesis Conditions

By using different times of sputtering and different value of partial pressure of oxygen in sputtering gas, Bi 2.1 Sr 1.9 CuO y thin films ( Bi :2201) were deposited onto heated single crystal (100) MgO substrates. The temperature dependence of the in-plane resistivity measured on epitaxial c-axis thin films is strongly influenced by the thin films synthesis conditions. Electrical resistivity changes strongly from optimal doping superconducting state to underdoped insulator state with decreasing partial pressure in sputtering gas. The increase of electrical resistance near superconducting transition were analyzed by using some theoretical models.

Electrical Properties and Microstructures of Ultraviolet Transparent Ga2O3 Thin Films

2007 ◽  
Vol 561-565 ◽  
pp. 1233-1236
Author(s):  
Yasuhiro Shigetoshi ◽  
Susumu Tsukimoto ◽  
Hidehisa Takeda ◽  
Kazuhiro Ito ◽  
Masanori Murakami
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Optical Properties ◽  
Electrical Properties ◽  
Substrate Temperature ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Partial Pressure Of Oxygen ◽  
Electrical And Optical Properties ◽  
Sputtering Deposition

The electrical and optical properties, and microstructures of 100 nm-thick Ga2O3 films fabricated on Al2O3(0001) substrates by a sputtering deposition were investigated. The partial pressure of oxygen was controlled and the substrate temperature was kept to be 500 °C during deposition. With increasing the oxygen partial pressure, the structures of the Ga2O3 films deposited on the substrates were observed to change from amorphous to crystalline (monoclinic β-type Ga2O3). The transmittance of the Ga2O3 films was measured to be more than 80 % at the visible and ultraviolet regions although the electrical resistivity was high. In order to obtain both low electrical resistivity and high transmittance at the ultraviolet regions, the addition of active dopant elements such as Sn into the Ga2O3 films would be required.

Observation by HVEM of the martensite transformation and the superconducting transition in Nb3Sn

1988 ◽  
Vol 46 ◽  
pp. 788-789
Author(s):  
M. A. Kirk ◽  
M. C. Baker ◽  
B. J. Kestel ◽  
H. W. Weber
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Superconducting State ◽  
Martensite Transformation ◽  
Sputter Deposition ◽  
Diffusion Reaction ◽  
Solute Diffusion ◽  
Superconducting Transition ◽  
Twin Boundaries ◽  
Martensite Structure

It is well known that a number of compound superconductors with the A15 structure undergo a martensite transformation when cooled to the superconducting state. Nb3Sn is one of those compounds that transforms, at least partially, from a cubic to tetragonal structure near 43 K. To our knowledge this transformation in Nb3Sn has not been studied by TEM. In fact, the only low temperature TEM study of an A15 material, V3Si, was performed by Goringe and Valdre over 20 years ago. They found the martensite structure in some foil areas at temperatures between 11 and 29 K, accompanied by faults that consisted of coherent twin boundaries on {110} planes. In pursuing our studies of irradiation defects in superconductors, we are the first to observe by TEM a similar martensite structure in Nb3Sn.Samples of Nb3Sn suitable for TEM studies have been produced by both a liquid solute diffusion reaction and by sputter deposition of thin films.

LOW TEMPERATURE RESISTIVITY OF TRANSITION ELEMENTS: VANADIUM, NIOBIUM, AND HAFNIUM

1957 ◽  
Vol 35 (8) ◽  
pp. 892-900 ◽  
Author(s):  
G. K. White ◽  
S. B. Woods
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Electrical Resistance ◽  
Thermal Resistivity ◽  
Superconducting Transition ◽  
Transition Elements ◽  
Pure Niobium ◽  
Temperature Resistivity ◽  
The Ideal

Measurements of the thermal conductivity from 2° to 90 ° K. and electrical conductivity from 2° to 300 ° K. are reported for vanadium, niobium, and hafnium. Although the vanadium and hafnium are not as pure as we might wish, measurements on these metals and on niobium allow a tabulation of the "ideal" electrical resistivity clue to thermal scattering for these elements from 300 ° K. down to about 20 ° K. Ice-point values of the "ideal" electrical resistivity are 18.3 μΩ-cm. for vanadium, 13.5 μΩ-cm. for niobium, and 29.4 μΩ-cm. for hafnium. Values for the "ideal" thermal resistivity of vanadium and niobium are deduced from the experimental results although for vanadium and more particularly for hafnium, higher purity specimens are required before a very reliable study of "ideal" thermal resistivity can be made. For the highly ductile pure niobium, the superconducting transition temperature, as determined from electrical resistance, appears to be close to 9.2 ° K.

scholarly journals Dependence on the Partial Pressure of Oxygen on the Shift in the Energy Band-gap of CdO Thin Films in the Visible Region

2001 ◽  
Vol 24 (1) ◽  
pp. 57-61 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro ◽  
S. L. Sapienza
Keyword(s):  
Thin Films ◽  
Partial Pressure ◽  
Band Gap ◽  
Energy Band ◽  
Visible Region ◽  
Point Of View ◽  
Theoretical Point ◽  
Partial Pressure Of Oxygen ◽  
Energy Band Gap ◽  
Cdo Thin Films

In this paper, the dependence on the partial pressure of oxygen of the shift in the energy band-gap of CdO thin films for the visible region is investigated from the theoretical point of view on an experimental basis. In our analysis, the role played by the dependence of the carrier density upon the above pressure is emphasized.

scholarly journals Electrical Characterization of La2-xSrxCuO4-y Superconductors

1989 ◽  
Vol 44 (1) ◽  
pp. 26-28 ◽  
Author(s):  
G. Chiodelli ◽  
G. Campari-Viganò ◽  
V. Massarotti ◽  
G. Flor
Keyword(s):  
Electrical Resistivity ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Solid Solutions ◽  
Electrical Characterization ◽  
Superconducting Transition ◽  
Electrical Behaviour ◽  
Temperature Range

Abstract The electrical behaviour of La2-xSrxCuO4-y solid solutions (with x = 0, x = 0.025, x = 0.05, and x = 0.15) at temperatures between 10 and 900 K and under different oxygen partial pressure pO2 = 1 ÷ 10-6 atm) has been investigated. The samples prepared and measured under an O2 flux (i.e., with y = 0) show a superconducting transition with Tc = 46, 29. 37 K for x = 0. 0.05 and 0.15, respectively. The samples with x = 0.025, y = 0, and x = 0, y ≠ 0 exhibit no sign of superconductivity. In the temperature range 100-900 K. La2CuO4 is semiconducting, whereas the electrical resistivity is independent of temperature for the x =0.025 sample, and the x = 0.05 and x = 0.15 are metallic.

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.

Theoretical analysis on the sensitivity to partial pressure of oxygen of the band gap shift in CdO thin films

2016 ◽  
Vol 30 (31) ◽  
pp. 1650371 ◽  
Author(s):  
M. A. Grado-Caffaro ◽  
M. Grado-Caffaro
Keyword(s):  
Thin Films ◽  
Partial Pressure ◽  
Band Gap ◽  
Cadmium Oxide ◽  
Visible Region ◽  
Visible Range ◽  
Partial Pressure Of Oxygen ◽  
Sensitivity Functions ◽  
Suitable Parameter ◽  
Cdo Thin Films

With the aim of providing an analytical approach (not accurate numerical results), for the first time, the sensitivity to the partial pressure of oxygen of the shift in the energy band gap experienced by cadmium-oxide thin films is evaluated for the visible region by introducing a suitable parameter. The sensitivity to the above pressure of the spatial carrier density is determined and compared with the sensitivity relative to the band gap shift. The gradient of the CdO carrier concentration as a function of the partial pressure of oxygen appears in the expressions for the two above sensitivity functions but the goal of this paper is not computing numerically this gradient so only qualitative estimations are done. In relation to the above results, the kinetics relative to the formation of CdO thin films are investigated. In addition, the sensitivity to the pressure in question of the corresponding optical-absorption shift in the visible range is calculated.

scholarly journals Controlling Electrical Conduction through Noble Metal Thin Films by Surface Plasmon Resonance

2020 ◽  
Vol 5 (3) ◽  
pp. 52
Author(s):  
Suresh C. Sharma ◽  
Vivek Khichar ◽  
Hussein Akafzade ◽  
Douglas Zinn ◽  
Nader Hozhabri
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Surface Plasmons ◽  
Noble Metal ◽  
Surface Plasmon ◽  
Polarized Light ◽  
Theoretical Models ◽  
Angle Of Incidence ◽  
Metal Thin Films ◽  
Resistivity Data

We have conducted in situ measurements of the surface plasmons and electrical resistivity of noble metal thin films. We present results for the electrical resistivity of these materials as functions of the angle of incidence for p-polarized light of wavelength λ = 632 nm in the Kretschmann configuration optical system. We observe a significantly lower resistivity (higher conductivity) under resonance conditions for the surface plasmon polaritons. The resistivity data are supported by COMSOL simulations of the evanescent fields associated with the surface plasmons. We discuss the resistivity data in terms of the theoretical models, which suggest that the electrical conductivity of the transition metals is sensitive to Umklapp electron-electron scattering and attractive interactions between free electrons because of the screening of the d-band electrons by the s-band electrons.

ELECTRICAL CHARACTERIZATION OF EPITAXIAL BI:2201

2002 ◽  
Vol 16 (04) ◽  
pp. 127-133 ◽  
Author(s):  
A. V. POP ◽  
G. ILONCA ◽  
MARIANA POP ◽  
R. DELTOUR
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
Magnetron Sputtering ◽  
Normal State ◽  
Electrical Resistance ◽  
Electrical Characterization ◽  
Dc Magnetron Sputtering ◽  
Normal State Resistivity ◽  
Partial Pressures

Bi2.1Sr1.9CuOy thin films (Bi:2201) were deposited onto heated single crystal (100) MgO substrates using inverted cylindrical DC magnetron sputtering with different partial pressures of oxygen in a sputtering gas. The behavior of the normal state resistivity function of temperature is strongly influenced by the composition of sputtering gas used in thin films synthesis. Near the transition to the superconducting state, electrical resistivity changes strongly from "metallic" to insulator (MI). The origin for the increase of electrical resistance was analyzed using some models for the localization of mobile carriers. A good linearity is obtained for ln R as a function of Tα for α = 1/10 and for R as a function of ln T. The last behavior agrees with the pinning and fragmentation of 1D stripes in CuO2 planes.

Optical and electrical properties of solution processable TiOx thin films for solar cell and sensor applications

2011 ◽  
Vol 1352 ◽  
Author(s):  
Jiguang Li ◽  
Lin Pu ◽  
Mool C. Gupta
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Resistivity ◽  
Refractive Index ◽  
Solar Cells ◽  
Solar Cell ◽  
Electrical Properties ◽  
Thermal Annealing ◽  
Electrical Resistance ◽  
Optical And Electrical Properties

ABSTRACTRecently, few tens of nanometer thin films of TiOx have been intensively studied in applications for organic solar cells as optical spacers, environmental protection and hole blocking. In this paper we provide initial measurements of optical and electrical properties of TiOx thin films and it’s applications in solar cell and sensor devices. The TiOx material was made through hydrolysis of the precursor synthesized from titanium isopropoxide, 2-methoxyethanol, and ethanolamine. The TiOx thin films of thickness between 20 nm to 120 nm were obtained by spin coating process. The refractive index of TiOx thin films were measured using an ellipsometric technique and an optical reflection method. At room temperature, the refractive index of TiOx thin film was found to be 1.77 at a wavelength of 600 nm. The variation of refractive index under various thermal annealing conditions was also studied. The increase in refractive index with high temperature thermal annealing process was observed, allowing the opportunity to obtain refractive index values between 1.77 and 2.57 at a wavelength 600 nm. The refractive index variation is due to the TiOx phase and density changes under thermal annealing.The electrical resistance was measured by depositing a thin film of TiOx between ITO and Al electrode. The electrical resistivity of TiOx thin film was found to be 1.7×107 Ω.cm as measured by vertical transmission line method. We have also studied the variation of electrical resistivity with temperature. The temperature coefficient of electrical resistance for 60 nm TiOx thin film was demonstrated as - 6×10-3/°C. A linear temperature dependence of resistivity between the temperature values of 20 – 100 °C was observed.The TiOx thin films have been demonstrated as a low cost solution processable antireflection layer for Si solar cells. The results indicate that the TiOx layer can reduce the surface reflection of the silicon as low as commonly used vacuum deposited Si3N4 thin films.

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