Radiation detection from phase-locked serial dc SQUID arrays

DEFF Research Database (Denmark)

Kaplunenko, V. K.; Mygind, Jesper; Pedersen, Niels Falsig

1993-01-01

We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac[approximately-e......We report on synchronous operation of series arrays of inductively coupled superconducting quantum interference devices (SQUIDs). Each array consisted of N=3 or 11 dc SQUIDs with common inductances providing a strong interaction between neighboring cells. Externally shunted (betac...

High-Tc dc-SQUID gradiometers in flip-chip configuration

International Nuclear Information System (INIS)

Peiselt, K; Schmidl, F; Linzen, S; Anton, A S; Huebner, U; Seidel, P

2003-01-01

We describe a new design of a gradiometric flip-chip antenna, which is inductively coupled to a dc-SQUID gradiometer. Both components are patterned out of thin films of the high-T c superconductor YBa 2 Cu 3 O 7-x (YBCO). For the flip-chip antenna, a 40 mm x 10 mm SrTiO 3 single crystalline substrate is used, while the gradiometer sensors are prepared on 10 mm x 10 mm SrTiO 3 bicrystal substrates. Special attention is paid to the inductive coupling between the flip-chip antenna and the read-out gradiometer antenna. We investigate different designs of coupling loops in order to optimize the coupling inductance between both components of the sensor. With optimized coupling the sensor achieves a field-gradient resolution of 12 fT cm -1 Hz -1/2 in the white noise region and of 310 fT cm -1 Hz -1/2 at 1 Hz in the unshielded laboratory environment

High-Tc dc-SQUID gradiometers in flip-chip configuration

Science.gov (United States)

Peiselt, K.; Schmidl, F.; Linzen, S.; Anton, A. S.; Hübner, U.; Seidel, P.

2003-12-01

We describe a new design of a gradiometric flip-chip antenna, which is inductively coupled to a dc-SQUID gradiometer. Both components are patterned out of thin films of the high-Tc superconductor YBa2Cu3O7-x (YBCO). For the flip-chip antenna, a 40 mm × 10 mm SrTiO3 single crystalline substrate is used, while the gradiometer sensors are prepared on 10 mm × 10 mm SrTiO3 bicrystal substrates. Special attention is paid to the inductive coupling between the flip-chip antenna and the read-out gradiometer antenna. We investigate different designs of coupling loops in order to optimize the coupling inductance between both components of the sensor. With optimized coupling the sensor achieves a field-gradient resolution of 12 fT cm-1 Hz-1/2 in the white noise region and of 310 fT cm-1 Hz-1/2 at 1 Hz in the unshielded laboratory environment.

Computer model for noise in the dc Squid

International Nuclear Information System (INIS)

Tesche, C.D.; Clarke, J.

1976-08-01

A computer model for the dc SQUID is described which predicts signal and noise as a function of various SQUID parameters. Differential equations for the voltage across the SQUID including the Johnson noise in the shunted junctions are integrated stepwise in time

UHV-cluster-tool for fabrication of thin film structures and transport- and noise properties of YBa2Cu3O7-δ grain boundary-SQUIDs

International Nuclear Information System (INIS)

Back, Christoph

2007-01-01

A UHV-thin-film-deposition system for the fabrication of thin film structures of metals and oxides was designed and optimized. For oxide materials, Pulsed Laser Deposition (PLD) was implemented. Epitaxial thin film growth can be analyzed during the PLD process by high-pressure RHEED (Reflection High-Energy Electron Diffraction). Furthermore layer-by-layer growth can be triggered by Pulsed Laser Intervall Deposition (PLiD). Heteroepitaxial multilayers can be fabricated automatically. Metal thin films can be grown by planar magnetron sputtering and by electron beam evaporation. Furthermore the system contains an rf-plasma source for surface cleaning and Ion Beam Etching (IBE). The three different deposition techniques are located in separate vacuum chambers which are connected by a central handling chamber allowing to combine all these processes in-situ. Furthermore superconducting quantum interference devices (SQUIDs) were fabricated out of epitaxially grown high-temperature superconducting YBa 2 Cu 3 O 7 -films on bicrystals. The SQUIDs were structured using a combined process of ion milling and chemical wet etching. By this combined etching process, edge signals that appear during imaging of flux quanta by low temperature scanning microscopy can be avoided. The transport- and noise properties of the SQUIDs were investigated. (orig.)

Fundamental characteristics of the QFP measured by the dc SQUID

International Nuclear Information System (INIS)

Shimizu, N.; Harada, Y.; Miyamoto, N.; Hosoya, M.; Goto, E.

1989-01-01

This paper describes the fundamental characteristics of the Quantum Flux Parametron (QFP) measured by a new method in which the output signals of the QFP are detected with a dc SQUID. The dc SQUID linearly and continuously converts the output current of the QFP to voltage, allowing the output signal of the QFP to be measured as the voltage of the dc SQUID. Thus, the fundamental characteristics of the QFP have been experimentally confirmed in detail

High critical current density YBCO films and fabrication of dc-SQUIDs

CERN Document Server

Kuriki, S; Kawaguchi, Y; Matsuda, M; Otowa, T

2002-01-01

In order to improve the sensitivity of SQUID magnetometers made of high-T sub c films, we have studied the conditions of pulsed-laser deposition of YBCO films. Among the different deposition parameters examined, extensive degassing of the vacuum chamber before and precise control of the substrate temperature during the film deposition were found effective for obtaining high critical temperature T sub c and high critical current density J sub c. It was also found that the residual-resistance ratio has a clear correlation with J sub c , indicating that it can be a good, and easy to measure, index of the film quality. Films having T sub c approx 89-90 K and J sub c >= 5x10 sup 6 A cm sup - sup 2 at 77 K were used to fabricate SQUIDs without a pickup loop. Grain-boundary junctions formed on bicrystal substrates with a 30 deg. misorientation angle exhibited I sub c R sub n values of more than 100 mu V at 77 K. The well-known scaling behaviour of the relation I sub c R sub n propor to (J sup G sup B sub c) sup 1 su...

High transition-temperature SQUID magnetometers and practical applications

International Nuclear Information System (INIS)

Dantsker, E.; Lawrence Berkeley National Lab., CA

1997-05-01

The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa 2 Cu 3 O 7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO 3 -YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz -1/2 at 1 Hz and 8.5 fT Hz -1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz -1/2 at 1 Hz and 18 fT Hz -1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room

Design consideration for dc SQUIDs fabricated in deep sub-micron technology

International Nuclear Information System (INIS)

Ketchen, M.B.

1991-01-01

Design rules for scaling dc SQUID junctions to optimize SQUID performance have been well known for over a decade, and verified down to the sub-micron regime. Practical SQUIDs having well coupled input coils of usable inductance have generally been fabricated at the 2-5 μm level of lithography. Other technologies, silicon in particular, are now routinely practiced at the 0.5 μm level of lithography with impressive demonstrations at the 0.1-0.25 μm level not uncommon. In this paper the implications of applying such fabrication capability to advance dc SQUID technology are explored. In particular the issues of scaling practical dc SQUIDs down to the 0.1-0.25 μm regime are examined, using as a prototype design the basic washer SQUID with a spiral input coil

Static and dynamic magnetization properties of Y1Ba2Cu3Oz thin films

International Nuclear Information System (INIS)

Sekula, S.T.

1989-08-01

Magnetization studies were carried out on Y 1 Ba 2 Cu 3 O z (YBCO) thin films that were e-beam evaporated onto circular discs of single-crystal SrTiO 3 with (001) and (110) faces as well as KTaO 3 with (001) faces. The measurements were made using vibrating sample (VSM) and SQUID-based magnetometry with the applied field perpendicular to the substrate surface. Critical current densities J c (H,T) are deduced from the magnetic hysteresis. Flux creep effects are observed over longer periods with the SQUID magnetometer. Analysis of the results of low frequency response of these films to collinear ac and dc magnetic fields are compared with the dc magnetometry results. J c (H,T) is observed to be quite sensitive to the type of epitaxial growth on the various substrates. 16 refs., 10 figs

High transition-temperature SQUID magnetometers and practical applications

Energy Technology Data Exchange (ETDEWEB)

Dantsker, Eugene [Univ. of California, Berkeley, CA (United States). Dept. of Physics

1997-05-01

The design, fabrication and performance of SQUID magnetometers based on thin films of the high-transition temperature superconductor YBa₂Cu₃O_7-x (YBCO) are described. Essential to the achieving high magnetic field resolution at low frequencies is the elimination of 1/f flux noise due to thermally activated hopping of flux vortices between pinning sites in the superconducting films. Through improvements in processing, 1/f noise in single layer YBCO thin films and YBCO-SrTiO₃-YBCO trilayers was systematically reduced to allow fabrication of sensitive SQUID magnetometers. Both single-layer directly coupled SQUID magnetometers and multilayer magnetometers were fabricated, based on the dc SQUID with bicrystal grain boundary Josephson junctions. Multilayer magnetometers had a lower magnetic field noise for a given physical size due to greater effective sensing areas. A magnetometer consisting of a SQUID inductively coupled to the multiturn input coil of a flux transformer in a flip-chip arrangement had a field noise of 27 fT Hz^-1/2 at 1 Hz and 8.5 fT Hz^-1/2 at 1 kHz. A multiloop multilayer SQUID magnetometer had a field noise of 37 fT Hz^-1/2 at 1 Hz and 18 fT Hz^-1/2 at 1 kHz. A three-axis SQUID magnetometer for geophysical applications was constructed and operated in the field in the presence of 60 Hz and radiofrequency noise. Clinical quality magnetocardiograms were measured using multilayer SQUID magnetometers in a magnetically shielded room.

Macroscopic quantum tunneling in a dc SQUID

International Nuclear Information System (INIS)

Chen, Y.C.

1986-01-01

The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current

Compact integrated dc SQUID gradiometer

Science.gov (United States)

de Waal, V. J.; Klapwijk, T. M.

1982-10-01

An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17×12 mm and a sensitivity of 3.5×10-12 T m-1 Hz-1/2.

Ion implantation in superconducting niobium and Nb3 Sn thin films: adjustment of Josephson microbridges and SQUID devices

International Nuclear Information System (INIS)

Robic, J.Y.; Piaguet, J.; Duret, D.; Veler, J.C.; Veran, J.L.; Zenatti, D.

1978-01-01

The principles of operation of Josephson junctions and SQUIDS are resumed. An ion implantation technique for the adjustment of the critical current is presented. High quality superconducting thin films were obtained by electron gun evaporation of niobium on heated substrates. Polycrystalline Nb 3 Sn was made by annealing (1000 K, 10 -6 Torr) a multilayer structure of successively evaporated niobium and thin films. Selected ions (helium, neon, argon) were implanted at doses ranging from 10 13 to 10 17 cm -2 . After implantation the critical temperature, the critical current and the normal resistivity were measured on special photoetched geometries. The variations of these electrical properties depend on the nuclear energy loss. The critical temperature of Nb 3 Sn is decreased by ion implantation and can be increased again by a new annealing. The parameters of the ion implantation were defined in order to obtain a critical temperature slightly higher than the operating temperature. The geometries of the microbridges and the implanted areas where then chosen to obtain appropriate criticals currents (approximately 10 μA) at the operating temperature. The obtained microbridges were used as junction elements in superconducting quantum interference devices (SQUID)

Dc-SQUID sensor system for multichannel neuromagnetometry

Energy Technology Data Exchange (ETDEWEB)

Houwman, E.P.; Veldhuis, D.; Flokstra, ter Brake, H.J.M.; Jaszczuk, W.; Rogalla, H. (Univ. of Twente, Faculty of Applied Physics, P.O. Box 217, 7500 AE Enschede (NL)); Martinez, A. (Universidad de Zaragoza, E.T.S.I.I. Maria Zambrano 50, 50015 Zaragoza (ES))

1991-03-01

This paper reports on various DC-SQUID sensor configurations developed for use in the authors' 19-channel neuromagetometer. Apart from the standard type, resistively and indictively shunted SQUIDs were made, allowing for a large screening factor {beta} ({gt}1). In this way signal coupling from the pick-up coil to the SQUID is facilitated and capactive coupling between the input coil and the SQUID washer can be decreased. The number of turns of the input coil is decreased further by allowing for an inductance mismatch in the input circuit. Although theoretically both measures give rise to an increased field noise of the sensor, they may lead to a reduction of the excess noise and the noise balance may become positive.

Design of a hysteretic SQUID as the readout for a dc SQUID

International Nuclear Information System (INIS)

Gershenson, M.

1991-01-01

This paper present a design for an optimal hysteretic SQUID readout circuit for a DC SQUID, thus eliminating the need for bulky output transformers or resonance matching circuits. The hysteretic readout system, which is based in part on standard sampling theory, is compared to another similar system and shown to be superior in terms of slew rate and immunity of electromagnetic interference. The circuit will be useful in optimizing the performance of biomagnetic systems

Compact integrated dc SQUID gradiometer

Energy Technology Data Exchange (ETDEWEB)

de Waal, V.J.; Klapwijk, T.M.

1982-10-01

An all-niobium integrated system of first-order gradiometer and dc suprconducting quantum interference device (SQUID) has been developed. It is relatively simple to fabricate, has an overall size of 17 x 12 mm and a sensitivity of 3.5 x 10/sup -12/ T m/sup -1/ Hz/sup -1/2/.

Dielectric properties of DC reactive magnetron sputtered Al2O3 thin films

International Nuclear Information System (INIS)

Prasanna, S.; Mohan Rao, G.; Jayakumar, S.; Kannan, M.D.; Ganesan, V.

2012-01-01

Alumina (Al 2 O 3 ) thin films were sputter deposited over well-cleaned glass and Si substrates by DC reactive magnetron sputtering under various oxygen gas pressures and sputtering powers. The composition of the films was analyzed by X-ray photoelectron spectroscopy and an optimal O/Al atomic ratio of 1.59 was obtained at a reactive gas pressure of 0.03 Pa and sputtering power of 70 W. X-ray diffraction results revealed that the films were amorphous until 550 °C. The surface morphology of the films was studied using scanning electron microscopy and the as-deposited films were found to be smooth. The topography of the as-deposited and annealed films was analyzed by atomic force microscopy and a progressive increase in the rms roughness of the films from 3.2 nm to 4.53 nm was also observed with increase in the annealing temperature. Al-Al 2 O 3 -Al thin film capacitors were then fabricated on glass substrates to study the effect of temperature and frequency on the dielectric property of the films. Temperature coefficient of capacitance, AC conductivity and activation energy were determined and the results are discussed. - Highlights: ► Al 2 O 3 thin films were deposited by DC reactive magnetron sputtering. ► The films were found to be amorphous up to annealing temperature of 550 C. ► An increase in rms roughness of the films was observed with annealing. ► Al-Al 2 O 3 -Al thin film capacitors were fabricated and dielectric constant was 7.5. ► The activation energy decreased with increase in frequency.

Structure evolution of zinc oxide thin films deposited by unbalance DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Aryanto, Didik, E-mail: didi027@lipi.go.id [Research Center for Physics, Indonesian Institute of Sciences, Serpong 15314, Tangerang Selatan (Indonesia); Materials Research Group, Physics Department, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Marwoto, Putut; Sugianto [Physics Department, Faculty of Mathematics and Science, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Materials Research Group, Physics Department, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Sudiro, Toto [Research Center for Physics, Indonesian Institute of Sciences, Serpong 15314, Tangerang Selatan (Indonesia); Birowosuto, Muhammad D. [Research Center for Physics, Indonesian Institute of Sciences, Serpong 15314, Tangerang Selatan (Indonesia); CINTRA UMI CNRS/NTU/THALES 3288 Research Techno Plaza, 50 Nanyang Drive, Border X Block, level 6, 637553 (Singapore); Sulhadi [Physics Department, Faculty of Mathematics and Science, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia)

2016-04-19

Zinc oxide (ZnO) thin films are deposited on corning glass substrates using unbalanced DC magnetron sputtering. The effect of growth temperature on surface morphology and crystallographic orientation of ZnO thin film is studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The surface morphology and crystallographic orientation of ZnO thin film are transformed against the increasing of growth temperature. The mean grain size of film and the surface roughness are inversely and directly proportional towards the growth temperature from room temperature to 300 °C, respectively. The smaller grain size and finer roughness of ZnO thin film are obtained at growth temperature of 400 °C. The result of AFM analysis is in good agreement with the result of XRD analysis. ZnO thin films deposited in a series of growth temperatures have hexagonal wurtzite polycrystalline structures and they exhibit transformations in the crystallographic orientation. The results in this study reveal that the growth temperature strongly influences the surface morphology and crystallographic orientation of ZnO thin film.

Synthesis and characterization of DC magnetron sputtered nano structured molybdenum thin films

Energy Technology Data Exchange (ETDEWEB)

Rondiya, S. R.; Rokade, A. V.; Jadhavar, A. A.; Pandharkar, S. M.; Kulkarni, R. R.; Karpe, S. D.; Diwate, K. D. [School of Energy Studies, Savitribai Phule Pune University, Pune 411007 (India); Jadkar, S. R., E-mail: sandesh@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

2016-04-13

Molybdenum (Mo) thin films were deposited on corning glass (#7059) substrates using DC magnetron sputtering system. The effect of substrate temperature on the structural, morphology and topological properties have been investigated. Films were characterized by variety of techniques such as low angle x-ray diffraction (low angle XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM). The low angle XRD analysis revealed that the synthesized Mo films are nanocrystalline having cubic crystal structure with (110) preferential orientation. The microstructure of the deposited Mo thin films observed with FE-SEM images indicated that films are homogeneous and uniform with randomly oriented leaf shape morphology. The AFM analysis shows that with increase in substrate temperature the rms roughness of Mo films increases. The obtained results suggest that the synthesized nanostructured Mo thin films have potential application as a back contact material for high efficiency solar cells like CdTe, CIGS, CZTS etc.

Directly coupled YBCO dc SQUID magnetometers

International Nuclear Information System (INIS)

Petersen, P.R.E.; Shen, Y.Q.; Holst, T.; Larsen, B.H.; Sager, M.P.; Bindslev Hansen, J.

1999-01-01

YBa 2 Cu 3 O 7- x magnetometers have been made on 10mmx10mm MgO substrates by directly coupling the magnetometer pick-up loop to a dc SQUID with narrow strip lines. The dc SQUIDs were made with YBa 2 Cu 3 O 7-x step-edge Josephson junctions. The layout of the magnetometer pick-up loop was chosen as a compromise between maximizing the loop effective area and minimizing the loop inductance. The SQUID was designed to have L S ∼100 pH in order to obtain β L =2I 0 L S /Φ 0 approx.= 1 with the single-junction critical current I 0 ∼10 μA. We have made magnetometers with white noise levels down to 55 fT Hz -1/2 and a 1/f knee at 1 Hz (ac biased). Noise measurements were made on a field-cooled magnetometer. The noise measured at 1 Hz when cooled in 'zero field' was 175 fT Hz -1/2 . When cooled in magnetic fields of B = 50 μT and B = 100 μT we measured the noise at 1 Hz to be 430 fT Hz -1 2 and 1.3 pT Hz -1/2 , respectively. (author)

A new integrated microwave SQUID circuit design

International Nuclear Information System (INIS)

Erne, S.N.; Finnegan, T.F.

1980-01-01

In this paper we consider the design and operation of a planar thin-film rf-SQUID circuit which can be realized via microwave-integrated-circuit (MIC) techniques and which differs substantially from pervious microwave SQUID configurations involving either mechanical point-contact or cylindrical thin-film micro-bridge geometries. (orig.)

Low noise niobium dc SQUID with a planar input coil

Science.gov (United States)

de Waal, V. J.; van den Hamer, P.; Klapwijk, T. M.

1983-02-01

A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4×10-32 J/Hz. A 20-turn 1.2-μH input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1×10-30 J/Hz.

Characterisation of magnetron sputtered SmCo5 thin films

International Nuclear Information System (INIS)

Wang, Y.; Sood, D.K.; Kothari

1999-01-01

SmCo 5 thin films were deposited using DC magnetron sputtering on single crystal silicon substrate with chromium and SiO 2 top layers. Deposition was carried out at three different substrate temperatures: room temperature, 400 deg C and 600 deg C. Films were characterised by using Rutherford Backscattering Spectroscopy (RBS), X-ray Diffraction (XRD), Secondary Ion Mass Spectrometry (SIMS) and SQUID magnetometer. RBS analysis indicated that the films have excellent stoichiometry with the Sm to Co ratio of 1:5. This analysis also showed that the films deposited or annealed at high temperatures (≥600 deg C) indicated significant inter-diffusion at the interface between the barrier layer and the film. Oxygen was found to be the major impurity in the films. XRD data indicated that the films formed 1:5 and 2:17 phases under different deposition conditions. The preliminary studies of these films using magnetic force microscopy revealed the presence of magnetic domains

DC Magnetron Sputtered IZTO Thin Films for Organic Photovoltaic Application.

Science.gov (United States)

Lee, Hye Ji; Noviyana, Imas; Putri, Maryane; Koo, Chang Young; Lee, Jung-A; Kim, Jeong-Joo; Jeong, Youngjun; Lee, Youngu; Lee, Hee Young

2018-02-01

IZTO20 (In0.6Zn0.2Sn0.2O1.5) ceramic target was prepared from oxide mixture of In2O3, ZnO, and SnO2 powders. IZTO20 thin films were then deposited onto glass substrate at 400 °C by DC magnetron sputtering. The average optical transmittance determined by ultraviolet-visible spectroscopy was higher than 85% for all films. The minimum resistivity of the annealed IZTO20 thin film was approximately 6.1×10-4 Ω·cm, which tended to increase with decreasing indium content. Substrate heating and annealing were found to be important parameters affecting the electrical and optical properties. An organic photovoltaic (OPV) cell was fabricated using the IZTO20 film deposited under the optimized condition as an anode electrode and the efficiency of up to 80% compared to that of a similar OPV cell using ITO film was observed. Reduction of surface roughness and electrical resistivity through annealing treatment was found to contribute to the improved efficiency of the OPV cell.

Low noise niobium dc SQUID with a planar input coil

Energy Technology Data Exchange (ETDEWEB)

de Waal, V.J.; van den Hamer, P.; Klapwijk, T.M.

1983-02-15

A practical all-niobium dc superconducting quantum interference device (SQUID) with a niobium spiral input coil has been developed. The SQUID utilizes submicron Josephson junctions. The best intrinsic energy resolution obtained with a 1-nH SQUID is 4 x 10/sup -32/ J/Hz. A 20-turn 1.2-..mu..H input coil is coupled to a 2.3-nH SQUID with an efficiency of 0.5. The energy resolution with respect to the coil is 1 x 10/sup -30/ J/Hz.

Well coupled, low noise, dc SQUIDS

International Nuclear Information System (INIS)

Muhlfelder, B.; Beall, J.A.; Cromar, M.W.; Johnson, W.W.; Ono, R.H.

1985-01-01

The authors have designed, fabricated, and tested a Double Transformer (DT) coupled dc SQUID (Superconducting Quantum Interference Device) with low noise, an input inductance of 1μH and a smooth input-output characteristic. A transmission line model is presented to explain a resonance in the input-output characteristic of early versions of this device. Guided by the results of numerical simulations a new version of this device has been built and tested. Experimental results are presented that show that the resonance can be moved to a higher voltage by reducing the area of the SQUID loop. The voltage-external flux characteristic of some of these new devices agrees to within 10% with computer simulations. The minimum detectable energy per unit bandwidth (MDE) referred to the SQUID loop, is 10h, where h is Planck's constant. Computer simulations indicate an MDE of 6h

Structural and optical properties of DC reactive magnetron sputtered zinc aluminum oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Kumar, B. Rajesh, E-mail: rajphyind@gmail.com [Department of Physics, GITAM Institute of Technology, GITAM University, Visakhapatnam - 530 045, A.P. (India); Rao, T. Subba, E-mail: thotasubbarao6@gmail.com [Department of Physics, Sri Krishnadevaraya University, Anantapuramu - 515 003, A.P. (India)

2014-10-15

Highly transparent conductive Zinc Aluminum Oxide (ZAO) thin films have been deposited on glass substrates using DC reactive magnetron sputtering method. The thin films were deposited at 200 °C and post-deposition annealing from 15 to 90 min. XRD patterns of ZAO films exhibit only (0 0 2) diffraction peak, indicating that they have c-axis preferred orientation perpendicular to the substrate. Scanning electron microscopy (SEM) is used to study the surface morphology of the films. The grain size obtained from SEM images of ZAO thin films are found to be in the range of 20 - 26 nm. The minimum resistivity of 1.74 × 10{sup −4} Ω cm and an average transmittance of 92% are obtained for the thin film post annealed for 30 min. The optical band gap of ZAO thin films increased from 3.49 to 3.60 eV with the increase of annealing time due to Burstein-Moss effect. The optical constants refractive index (n) and extinction coefficient (k) were also determined from the optical transmission spectra.

Double-barrier junction based dc SQUID

NARCIS (Netherlands)

Bartolomé, M.E.; Brinkman, Alexander; Flokstra, Jakob; Golubov, Alexandre Avraamovitch; Rogalla, Horst

2000-01-01

dc SQUIDs based on double-barrier Nb/Al/AlOx/Al/AlOx/Al/Nb junctions (DBSQs) have been fabricated and tested for the first time. The current–voltage curves have been measured at temperatures down to 1.4 K. The critical current, Ic, dependence on the temperature T is partially described by the

Amorphous ITO thin films prepared by DC sputtering for electrochromic applications

International Nuclear Information System (INIS)

Teixeira, V.; Cui, H.N.; Meng, L.J.; Fortunato, E.; Martins, R.

2002-01-01

Indium-Tin-Oxide (ITO) thin films were deposited on glass substrates using DC magnetron reactive sputtering at different bias voltages and substrate temperatures. Some improvements were obtained on film properties, microstructure and other physical characteristics for different conditions. Amorphous and polycrystalline films can be obtained for various deposition conditions. The transmission, absorption, spectral and diffuse reflection of ITO films were measured in some ranges of UV-Vis-NIR. The refractive index (n), Energy band gap E g and the surface roughness of the film were derived from the measured spectra data. The carrier density (n c ) and the carrier mobility (μ) of the film micro conductive properties were discussed. The films exhibited suitable optical transmittance and conductivity for electrochromic applications

CrN thin films prepared by reactive DC magnetron sputtering for symmetric supercapacitors

KAUST Repository

Wei, Binbin; Liang, Hanfeng; Zhang, Dongfang; Wu, Zhengtao; Qi, Zhengbing; Wang, Zhoucheng

2016-01-01

stability are promising candidates as supercapacitor electrode materials. In this work, we report the fabrication of CrN thin films using reactive DC magnetron sputtering and further their applications for symmetric supercapacitors for the first time. The Cr

Origin of high carrier mobility and low residual stress in RF superimposed DC sputtered Al doped ZnO thin film for next generation flexible devices

Science.gov (United States)

Kumar, Naveen; Dubey, Ashish; Bahrami, Behzad; Venkatesan, S.; Qiao, Qiquan; Kumar, Mukesh

2018-04-01

In this work, the energy and flux of high energetic ions were controlled by RF superimposed DC sputtering process to increase the grain size and suppress grain boundary potential with minimum residual stress in Al doped ZnO (AZO) thin film. AZO thin films were deposited at different RF/(RF + DC) ratios by keeping total power same and were investigated for their electrical, optical, structural and nanoscale grain boundaries potential. All AZO thin film showed high crystallinity and orientation along (002) with peak shift as RF/(RF + DC) ratio increased from 0.0, pure DC, to 1.0, pure RF. This peak shift was correlated with high residual stress in as-grown thin film. AZO thin film grown at mixed RF/(RF + DC) of 0.75 showed high electron mobility, low residual stress and large crystallite size in comparison to other AZO thin films. The nanoscale grain boundary potential was mapped using Kelvin Probe Force Microscopy in all AZO thin film and it was observed that carrier mobility is controlled not only by grains size but also by grain boundary potential. The XPS analysis confirms the variation in oxygen vacancies and zinc interstitials which explain the origin of low grain boundaries potential and high carrier mobility in AZO thin film deposited at 0.75 RF/(RF + DC) ratio. This study proposes a new way to control the grain size and grain boundary potential to further tune the optoelectronic-mechanical properties of AZO thin films for next generation flexible and optoelectronic devices.

Microstructural variation in titanium oxide thin films deposited by DC magnetron sputtering

International Nuclear Information System (INIS)

Pandian, Ramanathaswamy; Natarajan, Gomathi; Kamruddin, M.; Tyagi, A.K.

2013-01-01

We report on the microstructural evolution of titanium oxide thin films deposited by reactive DC magnetron sputtering using titanium metal target. By varying the ratio of sputter-gas mixture containing argon, oxygen and nitrogen various phases of titanium oxide, almost pure rutile, rutile-rich and anatase-rich nano-crystalline, were deposited on Si substrates at room temperature. Using high-resolution scanning electron microscopy, X-ray diffraction and micro-Raman techniques the microstructure of the films were revealed. The relationship between the microstructure of the films and the oxygen partial pressure during sputtering is discussed

Dielectric properties of DC reactive magnetron sputtered Al{sub 2}O{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Prasanna, S. [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Mohan Rao, G. [Department of Instrumentation, Indian Institute of Science (IISc), Bangalore, 560 012 (India); Jayakumar, S., E-mail: s_jayakumar_99@yahoo.com [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Kannan, M.D. [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore, 641 004 (India); Ganesan, V. [Low Temperature Lab, UGC-DAE Consortium for Scientific Research (CSR), Indore, 452 017 (India)

2012-01-31

Alumina (Al{sub 2}O{sub 3}) thin films were sputter deposited over well-cleaned glass and Si < 100 > substrates by DC reactive magnetron sputtering under various oxygen gas pressures and sputtering powers. The composition of the films was analyzed by X-ray photoelectron spectroscopy and an optimal O/Al atomic ratio of 1.59 was obtained at a reactive gas pressure of 0.03 Pa and sputtering power of 70 W. X-ray diffraction results revealed that the films were amorphous until 550 Degree-Sign C. The surface morphology of the films was studied using scanning electron microscopy and the as-deposited films were found to be smooth. The topography of the as-deposited and annealed films was analyzed by atomic force microscopy and a progressive increase in the rms roughness of the films from 3.2 nm to 4.53 nm was also observed with increase in the annealing temperature. Al-Al{sub 2}O{sub 3}-Al thin film capacitors were then fabricated on glass substrates to study the effect of temperature and frequency on the dielectric property of the films. Temperature coefficient of capacitance, AC conductivity and activation energy were determined and the results are discussed. - Highlights: Black-Right-Pointing-Pointer Al{sub 2}O{sub 3} thin films were deposited by DC reactive magnetron sputtering. Black-Right-Pointing-Pointer The films were found to be amorphous up to annealing temperature of 550 C. Black-Right-Pointing-Pointer An increase in rms roughness of the films was observed with annealing. Black-Right-Pointing-Pointer Al-Al{sub 2}O{sub 3}-Al thin film capacitors were fabricated and dielectric constant was 7.5. Black-Right-Pointing-Pointer The activation energy decreased with increase in frequency.

Two-stage SQUID systems and transducers development for MiniGRAIL

International Nuclear Information System (INIS)

Gottardi, L; Podt, M; Bassan, M; Flokstra, J; Karbalai-Sadegh, A; Minenkov, Y; Reinke, W; Shumack, A; Srinivas, S; Waard, A de; Frossati, G

2004-01-01

We present measurements on a two-stage SQUID system based on a dc-SQUID as a sensor and a DROS as an amplifier. We measured the intrinsic noise of the dc-SQUID at 4.2 K. A new dc-SQUID has been fabricated. It was specially designed to be used with MiniGRAIL transducers. Cooling fins have been added in order to improve the cooling of the SQUID and the design is optimized to achieve the quantum limit of the sensor SQUID at temperatures above 100 mK. In this paper we also report the effect of the deposition of a Nb film on the quality factor of a small mass Al5056 resonator. Finally, the results of Q-factor measurements on a capacitive transducer for the current MiniGRAIL run are presented

Transparent conducting Al-doped ZnO thin films prepared by magnetron sputtering with dc and rf powers applied in combination

International Nuclear Information System (INIS)

Minami, Tadatsugu; Ohtani, Yuusuke; Miyata, Toshihiro; Kuboi, Takeshi

2007-01-01

A newly developed Al-doped ZnO (AZO) thin-film magnetron-sputtering deposition technique that decreases resistivity, improves resistivity distribution, and produces high-rate depositions has been demonstrated by dc magnetron-sputtering depositions that incorporate rf power (dc+rf-MS), either with or without the introduction of H 2 gas into the deposition chamber. The dc+rf-MS preparations were carried out in a pure Ar or an Ar+H 2 (0%-2%) gas atmosphere at a pressure of 0.4 Pa by adding a rf component (13.56 MHz) to a constant dc power of 80 W. The deposition rate in a dc+rf-MS deposition incorporating a rf power of 150 W was approximately 62 nm/min, an increase from the approximately 35 nm/min observed in dc magnetron sputtering with a dc power of 80 W. A resistivity as low as 3x10 -4 Ω cm and an improved resistivity distribution could be obtained in AZO thin films deposited on substrates at a low temperature of 150 deg. C by dc+rf-MS with the introduction of hydrogen gas with a content of 1.5%. This article describes the effects of adding a rf power component (i.e., dc+rf-MS deposition) as well as introducing H 2 gas into dc magnetron-sputtering preparations of transparent conducting AZO thin films

Inductance-dependent characteristics of HTS dc-SQUID amplifiers

International Nuclear Information System (INIS)

Mitchell, E.E.; Tilbrook, D.L.; Foley, C.P.; MacFarlane, J.

2002-01-01

Full text: We have experimentally determined the transfer function V Φ and noise S Φ of several high temperature superconducting (HTS) dc SQUIDs of increasing loop size, while they were operated (without input flux transformer) in a small-signal-amplifier (open-loop) mode. A primary aim of our investigation was to provide reliable inductance data to aid our design of subsequent magnetometer devices. Flux was induced by means of current injection via a well-defined stripline directly into the SQUID loop. The loop size was systematically incremented in a range of otherwise similar SQUIDs. For each SQUID, the ratio between the induced flux and the injection current (which we define as the coupling inductance of the device, L c ) was measured as a function of the injection path length and the SQUID loop dimensions. Both L c and the derived SQUID self-inductance, L sq , were then compared with theoretical values, and contributions due to kinetic inductance and junction inductance were estimated. Correlations between the inductance data and our measured values of transfer function V Φ and noise S Φ were compared with previous results. Guidelines for optimisation of gradiometer SQUIDs were established, and in particular, the importance of achieving a large value transfer function together with a relatively small inductance was demonstrated. The strong influence of an enhanced transfer function was further emphasised when an order-of-magnitude reduction in noise was achieved by subjecting one of our SQUIDs to an in-house 'ion-beam trimming' process

High-T /SUB c/ Superconducting integrated circuit: a dc SQUID with input coil

International Nuclear Information System (INIS)

Di Iorio, M.S.; Beasley, M.R.

1985-01-01

We have fabricated a high transition temperature superconducting integrated circuit consisting of a dc SQUID and an input coupling coil. The purpose is to ascertain the generic problems associated with constructing a high-T /SUB c/ circuit as well as to fabricate a high performance dc SQUID. The superconductor used for both the SQUID and the input coil is Nb 3 Sn which must be deposited at 800 0 C. Importantly, the insulator separating SQUID and input coil maintains its integrity at this elevated temperature. A hole in the insulator permits contact to the innermost winding of the coil. This contact has been achieved without significant degradation of the superconductivity. Consequently, the device operates over a wide temperature range, from below 4.2 K to near T /SUB c/

Deposition, characterization, and electronic applications of YBa2Cu3O7 thin films

International Nuclear Information System (INIS)

Kromann, R.

1992-09-01

YBa 2 Cu 3 O 7 thin films were deposited by rf sputtering and laser ablation. In the case of rf sputtering the presence of negative oxygen ions was found to give rise to severe resputtering effects. In contrast, laser ablation is found to be a much simpler and more reliable depostion method. Structural characterization in the form of an X-ray diffraction study of the structure of laser ablated YBCO thin films is reported. Two films on MgO differing by 75% in the critical current density were examined. The difference was ascribed to the fact that about 5% of the grains in the low J c film grow 45 deg. misoriented with respect to the dominant orientation in the a-b plane. Two other films on SrTiO 3 differing by 70% in J c were examined. Various ways of achieving a 45 deg. grain boundary by a biepitaxial process on MgO substrates are described. The grain boundary junctions are used to fabricate DC SQUIDs. It is demonstrated that the SQUIDs exhibit critical current modulation in a magnetic field at temperatures up to 80 K. It is shown that the 1/f noise can be reduced by a factor of 3 by the double modulation technique, indicating that the dominant contribution to the 1/f noise comes from critical current fluctuations. The high level of 1/f noise from critical current fluctuations is ascribed to the nature of the 45 deg. grain boundary and it is argued that it is necessary to develop a bi-epitaxial process for grain boundaries with angles less than 45 deg.. Finally, it is demonstrated that a SQUID and a flux transformer can be fabricated on the same substrate to form an integrated magnetometer. (au) (8 tabs., 58 ills., 97 refs.)

Temperature dependence of the effective sensing area of high-Tc dc SQUIDs

International Nuclear Information System (INIS)

Brake, H.J.M. ter; Aarnink, W.A.M.; Bosch, P.J. van den; Hilgenkamp, J.W.M.; Flokstra, J.; Rogalla, H.

1997-01-01

The effective sensing area of a high-T c dc SQUID depends on temperature. As a consequence, fluctuations in the operating temperature result in apparent magnetic field noise if the SQUID is placed in a background magnetic field. An analysis of this effect for two SQUID types, the square-washer 'Ketchen' type and the inductively shunted type, is performed. For magnetocardiography, the temperature fluctuations (peak to peak) of the latter SQUID type should be below w 0.3 mK at 77 K, and below 2 mK at 55 K, with an earth's field suppression of 40 dB. For the square-washer SQUID the requirements are about 8 times less stringent. (author)

DC Magnetron sputtering of Y-Ba-Cu-O thin films

International Nuclear Information System (INIS)

Larsson, Gunnar.

1990-01-01

I have been studying dc magnetron sputtering of thin film YBa 2 Cu 3 O 6+x , one of the recently discovered high- temperatures superconductors. In the introduction a brief review of the subjects sputtering and superconductivity is given. Since partial pressure measurements, especially for oxygen, have been important in the work I include a short description of the operating principles of mass spectroscopy. Experimental results in addition to what is given in the papers concerning plasma are presented in an appendix at the end of the introduction. (au)

Synthesis and characterization of DC magnetron sputtered ZnO thin films under high working pressures

International Nuclear Information System (INIS)

Hezam, M.; Tabet, N.; Mekki, A.

2010-01-01

ZnO thin films were deposited on glass substrates using direct current (dc) magnetron sputtering under high working pressures. A pure zinc target was used, and sputtering was carried out in an oxygen atmosphere. The working pressure was varied between 50 and 800 mTorr. XRD characterization showed that for a window of working pressures between 300 and 500 mTorr, the deposited films were polycrystalline, with strong preferential orientation of grains along the c-axis. The film deposited at 400 mTorr had the highest (002) peak with the largest estimated grain size. Outside this window, the crystallinity and c-orientation of grains are lost. The microstructure of the films was investigated by Atomic Force microscopy (AFM). Optical transparency of the films was about 85%. The films produced were highly resistive, which might provide new alternatives for the synthesis of ZnO thin films aimed for SAW devices.

CrN thin films prepared by reactive DC magnetron sputtering for symmetric supercapacitors

KAUST Repository

Wei, Binbin

2016-12-29

Supercapacitors have been becoming indispensable energy storage devices in micro-electromechanical systems and have been widely studied over the past few decades. Transition metal nitrides with excellent electrical conductivity and superior cycling stability are promising candidates as supercapacitor electrode materials. In this work, we report the fabrication of CrN thin films using reactive DC magnetron sputtering and further their applications for symmetric supercapacitors for the first time. The CrN thin film electrodes fabricated under the deposition pressure of 3.5 Pa show an areal specific capacitance of 12.8 mF cm at 1.0 mA cm and high cycling stability with 92.1% capacitance retention after 20 000 cycles in a 0.5 M HSO electrolyte. Furthermore, our developed CrN//CrN symmetric supercapacitor can deliver a high energy density of 8.2 mW h cm at the power density of 0.7 W cm along with outstanding cycling stability. Thus, the CrN thin films have great potential for application in supercapacitors and other energy storage systems.

Deposition of Cu-doped PbS thin films with low resistivity using DC sputtering

Directory of Open Access Journals (Sweden)

Hariyadi Soetedjo

2018-03-01

Full Text Available Investigation of the electrical resistivity of Cu-doped PbS thin films has been carried out. The films were prepared using a DC sputtering technique. The doping was achieved by introducing the Cu dopant plate material directly on the surface of the PbS sputtering target plate. SEM-EDX data shows the Cu concentration in the PbS film to be proportional to the Cu plate diameter. The XRD pattern indicates the film is in crystalline cubic form. The Hall effect measurement shows that Cu doping yields an increase in the carrier concentration to 3.55 × 1019 cm−3 and a significant decrease in electrical resistivity. The lowest resistivity obtained was 0.13 Ωcm for a Cu concentration of 18.5%. Preferential orientation of (1 1 1 and (2 0 0 occurs during deposition. Keywords: Thin films, Lead sulfide, Sputtering, Resistivity, Semiconductor, Infrared

Noise characteristics of a dc SQUID with a resistively shunted inductance

International Nuclear Information System (INIS)

Enpuku, K.; Muta, T.; Yoshida, K.; Irie, F.

1985-01-01

Noise characteristics of a dc SQUID with an inductance shunted by a damping resistance are studied numerically. It is shown that the damping resistance improves considerably the resolution of the SQUID in the case of large β, where β = 2LI 0 /Phi 0 , I 0 is a critical current, L is a loop inductance and Phi 0 is the flux quantum. The energy resolutions for β = 4 and β = 10 are only about 2 and 4 times larger than that for β = 1, respectively. Furthermore, the ranges of both the bias current and the external flux, where good resolution is obtained, become very wide compared with the conventional SQUID. Therefore, the SQUID with the damping resistance can be used for large β (or L) without the significant degradation of the resolution, and will much improve the coupling properties between the SQUID and the input circuitry. The numerical simulation results are also compared with analytical ones, and a reasonable agreement is obtained

Low-frequency nuclear quadrupole resonance with a dc SQUID

International Nuclear Information System (INIS)

Chang, J.W.

1991-07-01

Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs

Preliminary study of CdTe and CdTe:Cu thin films nanostructures deposited by using DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Marwoto, Putut; Made, D. P. Ngurah; Sugianto [Departement of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Wibowo, Edy; Astuti, Santi Yuli; Aryani, Nila Prasetya [Materials Research Group, Laboratory of Thin Film, Department of Physics, Universitas Negeri Semarang, Gunungpati, Semarang 50229 Jawa Tengah (Indonesia); Othaman, Zulkafli [Departement of Physics, Universiti Teknologi Malaysia (UTM), Skudai, Johor Bahru (Malaysia)

2013-09-03

Growth and properties of CdTe and CdTe:Cu thin films nanostrucures deposited by using dc magnetron sputtering are reported. Scanning electron microscope (SEM) was used to observe the surface morphologies of the thin films. At growth conditions of 250 °C and 14 W, CdTe films did not yet evenly deposited. However, at growth temperature and plasma power of 325 °C and 43 W, both CdTe and CdTe:Cu(2%) have deposited on the substrates. In this condition, the morphology of the films indicate that the films have a grain-like nanostructures. Grain size diameter of about 200 nm begin to appear on top of the films. Energy Dispersive X-rays spectroscopy (EDX) was used to investigate chemical elements of the Cu doped CdTe film deposited. It was found that the film deposited consist of Cd, Te and Cu elements. XRD was used to investigate the full width at half maximum (FWHM) values of the thin films deposited. The results show that CdTe:Cu(2%) thin film has better crystallographic properties than CdTe thin film. The UV-Vis spectrometer was used to investigate the optical properties of thin films deposited. The transmittance spectra showed that transmittance of CdTe:Cu(2%) film is lower than CdTe film. It was found that the bandgap energy of CdTe and CdTe:Cu(2%) thin films of about 1.48 eV.

Simulation and optimization of a dc SQUID with finite capacitance

Energy Technology Data Exchange (ETDEWEB)

de Waal, V.J.; Schrijner, P.; Llurba, R.

1984-02-01

This paper deals with the calculations of the noise an the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT = 1.2 and 5 nHK. Within a range of ..beta.. and ..beta../sub c/ between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 nHK.

Simulation and optimization of a dc SQUID with finite capacitance

Science.gov (United States)

de Waal, V. J.; Schrijner, P.; Llurba, R.

1984-02-01

This paper deals with the calculations of the noise and the optimization of the energy resolution of a dc SQUID with finite junction capacitance. Up to now noise calculations of dc SQUIDs were performed using a model without parasitic capacitances across the Josephson junctions. As the capacitances limit the performance of the SQUID, for a good optimization one must take them into account. The model consists of two coupled nonlinear second-order differential equations. The equations are very suitable for simulation with an analog circuit. We implemented the model on a hybrid computer. The noise spectrum from the model is calculated with a fast Fourier transform. A calculation of the energy resolution for one set of parameters takes about 6 min of computer time. Detailed results of the optimization are given for products of inductance and temperature of LT=1.2 and 5 nH K. Within a range of β and β c between 1 and 2, which is optimum, the energy resolution is nearly independent of these variables. In this region the energy resolution is near the value calculated without parasitic capacitances. Results of the optimized energy resolution are given as a function of LT between 1.2 and 10 mH K.

High temperature superconducting devices for SQUIDs, HF- and FIR-applications. Subproject: Thin-film heterostructures for devices and loss mechanisms in HTS. Final report

International Nuclear Information System (INIS)

Froehlich, O.

1994-06-01

The successful use of electronic devices fabricated from the High Temperature Superconductors (HTS) in SQUID systems as well as HF- and FIR-applications requires the development of a suitable thin-film and device technology. Within the present research project we successfully established the technological base for the deposition and patterning of epitaxial HTS thin-films (YBaCuO, NdCeCuO) and heterostructures of HTS and insulating materials (e.g. NdGaO 3 ). YBaCuO/NdCeCuO superlattices could be successfully fabricated such that both components of the hterostructure were in a superconducting state. This allows for the fabrication and study of superconducting p-n structures. With respect to the fabrication of single grain boundary Josephson junctions based on the bicrystal technique we could establish an international leadership. The small spread of the junction parameters (∝20%) allowed the controllable fabrication of simple devices such as SQUIDs or flux-flow transistors. By the development of a new measuring technique the homogeneity of the critical current density distribution in grain-boundary junctions could be investigated on a sub-μm-scale. Within this project we also could establish a good understanding of the physical background of the transport phenomena in the mixed state of HTS in the presence of a temperature gradient. (orig./MM) [de

Influence of inductance induced noise in an YBa2Cu3O7 dc-SQUID at high operation temperatures

DEFF Research Database (Denmark)

Nilsson, P. Å.; Claeson, T.; Hansen, J. B.

1994-01-01

The voltage modulation depth of a high T(c) dc-SQUID was measured at temperatures close to T(c) and compared to a model by Enpuku et al. where the flux noise from the SQUID inductance is taken into account. The device was an YBa2Cu3O7 dc-SQUID made on a bicrystal substrate of SrTiO3. The design w...

Investigation of ferromagnetism in oxygen deficient hafnium oxide thin films

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Krockenberger, Yoshiharu; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Suter, Andreas [PSI, Villingen (Switzerland); Wilhelm, Fabrice; Rogalev, Andrei [ESRF, Grenoble (France)

2008-07-01

Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by X-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films.

Effects of Annealing on TiN Thin Film Growth by DC Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Azadeh Jafari

2014-07-01

Full Text Available We have reviewed the deposition of titanium nitride (TiN thin films on stainless steel substrates by a DC magnetron sputtering method and annealing at different annealing temperatures of 500, 600, and 700°C for 120 min in nitrogen/argon atmospheres. Effects of annealing temperatures on the structural and the optical properties of TiN films were investigated using X-ray diffraction (XRD, atomic force microscope (AFM, field emission scanning electron microscopy (FESEM, and UV-VIS spectrophotometer. Our experimental studies reveal that the annealing temperature appreciably affected the structures, crystallite sizes, and reflection of the films. By increasing the annealing temperature to 700°C crystallinity and reflection of the film increase. These results suggest that annealed TiN films can be good candidate for tokamak first wall due to their structural and optical properties.

Low-frequency flux noise in YBCO dc SQUIDs cooled in static magnetic fields

International Nuclear Information System (INIS)

Sager, M.P.; Bindslev Hansen, J.; Petersen, P.R.E.; Holst, T.; Shen, Y.Q.

1999-01-01

The low-frequency flux noise in bicrystal and step-edge YBa 2 Cu 3 O x dc SQUIDs has been investigated. The width, w, of the superconducting strips forming the SQUID frame was varied from 4 to 42 μm. The SQUIDs were cooled in static magnetic fields up to 150 μT. Two types of low-frequency noise dominated, namely 1/f-like noise and random telegraph noise giving a Lorentzian frequency spectrum. The 1/f noise performance of the w = 4, 6 and 7 μm SQUIDs was almost identical, while the SQUIDs with w = 22 and 42 μm showed an order of magnitude higher noise level. Our analysis of the data suggests an exponential increase of the 1/f noise versus the cooling field, exhibiting a characteristic magnetic field around 40 μT. (author)

Gas Sensing Properties of Metal Doped WO3 Thin Film Sensors Prepared by Pulsed Laser Deposition and DC Sputtering Process

Science.gov (United States)

Bhuiyan, Md. Mosharraf Hossain; Ueda, Tsuyoshi; Ikegami, Tomoaki; Ebihara, Kenji

2006-10-01

Tungsten trioxide (WO3) thin films gas sensors were prepared by the KrF excimer pulsed laser deposition (PLD) method. The films were prepared on the quartz glass, silicon and also on the Al2O3 sensor substrates with platinum interdigitated electrodes. The effect of doping of the platinum (Pt), palladium (Pd) or gold (Au) on the WO3 thin film was also investigated. These metals were doped to the WO3 thin film by the DC sputtering process during the PLD. The substrate temperature and the oxygen pressure were 400 °C and 100 mTorr, respectively, during the deposition. The films were characterized by atomic force microscopy (AFM) and X-ray diffraction (XRD). The sensitivity of the prepared sensors to 60 ppm NO gas was examined using the two terminal resistance method in a chamber at atmospheric pressure and operating temperatures of 25-350 °C. The sensitivity of the WO3 thin films doped with Pt, Pd, or Au was found to be higher than that of the undoped WO3 thin film.

The role of target-to-substrate distance on the DC magnetron sputtered zirconia thin films' bioactivity

Energy Technology Data Exchange (ETDEWEB)

Thaveedeetrakul, Arisara [Department of Chemical Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand); Witit-anun, Nirun [Department of Physics, Burapha University, Chon Buri (Thailand); Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok (Thailand); Boonamnuayvitaya, Virote, E-mail: virote.boo@kmutt.ac.th [Department of Chemical Engineering, King Mongkut' s University of Technology Thonburi, Bangkok (Thailand)

2012-01-15

Zirconium dioxide thin films were deposited on 316L-stainless steel type substrates using DC unbalanced magnetron sputtering. The process parameter of this work was the target-to-substrate distance (d{sub t-s}), which was varied from 60 to 120 mm. The crystal structure and surface topography of zirconium dioxide thin films were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results demonstrate that all of the ZrO{sub 2} thin films are composed monoclinic phase. The film sputtered at short d{sub t-s} (60 mm) shows a rather heterogeneous, uneven surface. The grain size, roughness, and thickness of thin films were decreased by increasing d{sub t-s}. The bioactivity was assessed by investigating the formation of hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}) on the thin film surface soaked in simulated body fluids (SBF) for 7 days. XRD and scanning electron microscopy (SEM) were used to verify the formation of apatite layers on the samples. Bone-like apatites were formed on the surface of the ZrO{sub 2} thin film in SBF immersion experiments. A nanocrystalline hydroxyapatite (HA) with a particle size of 2-4 {mu}m was deposited. Higher crystallinity of HA on the surface was observed when the distance d{sub t-s} increased to more than 80 mm. Therefore, it seems that a d{sub t-s} greater than 80 mm is an important sputtering condition for inducing HA on the zirconia film.

Thermodynamics of a closed-cycle gas flow system for cooling a HTc dc-SQUID magnetometer

NARCIS (Netherlands)

van den Bosch, P.J.; van den Bosch, P.J.; ter Brake, Hermanus J.M.; van den Eijkel, G.C.; Boelens, J.P.; Holland, Herman J.; Verberne, J.F.C.; Rogalla, Horst

1994-01-01

A multichannel high-Tc dc-SQUID based heart-magnetometer is currently under development in our laboratory. The system is cooled by a cooler that, due to its magnetic interference, has to be separated from the SQUID unit. In the present prototype system a closed-cycle gas flow was chosen as the

Low noise SQUIDs

Science.gov (United States)

de Waal, V. J.

1983-02-01

The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer.

Low noise SQUIDs

Energy Technology Data Exchange (ETDEWEB)

De Waal, V.J.

1983-01-01

The present investigation deals with the design, fabrication, and limitations of very sensitive SQUID (Superconducting Quantum Interference Device) magnetometers. The SQUID magnetometer is based on a utilization of the Josephson effect. A description of the theoretical background is provided, and high performance DC SQUIDs with submicron niobium Josephson junctions are discussed, taking into account design considerations, fabrication, junction characterization, the performance of the SQUID and input coil, and the gradiometer performance. The simulation and optimization of a DC SQUID with finite capacitance is considered, giving attention to the implementation of a simulation procedure on a hybrid computer. 129 references.

Correlation between mass-spectrometer measurements and thin film characteristics using dcMS and HiPIMS discharges

International Nuclear Information System (INIS)

Ferrec, A.; Keraudy, J.; Jacq, S.; Jouan, P.Y.; Djouadi, M.A.; Schuster, F.

2014-01-01

In this work, chromium thin films were deposited using dcMS and HiPIMS technologies. To compare these technologies, we analyzed the ion flux and the Cr coating microstructure in the same plasma conditions. Ion flux was measured with a mass spectrometer in time-averaged for both discharge and time-resolved for HiPIMS discharge. Time-averaged measurements provided important information. First, the low energetic part of the ion energy distribution function (IEDF) was similar in dcMS and HiPIMS and second the high energetic component was more prominent in the HiPIMS discharge. Time-resolved measurements showed that the high energetic part of the ion flux reached the mass spectrometer faster than the lowest part. It is only after the pulse end that most of the thermalized ions arrived and then cooled the flux. The correlation of these results with microstructure analysis shows that energetic particles induced a higher film density and a smoother surface in HiPIMS compared to dcMS discharge. (authors)

Deposition of Cu-doped PbS thin films with low resistivity using DC sputtering

Science.gov (United States)

Soetedjo, Hariyadi; Siswanto, Bambang; Aziz, Ihwanul; Sudjatmoko

2018-03-01

Investigation of the electrical resistivity of Cu-doped PbS thin films has been carried out. The films were prepared using a DC sputtering technique. The doping was achieved by introducing the Cu dopant plate material directly on the surface of the PbS sputtering target plate. SEM-EDX data shows the Cu concentration in the PbS film to be proportional to the Cu plate diameter. The XRD pattern indicates the film is in crystalline cubic form. The Hall effect measurement shows that Cu doping yields an increase in the carrier concentration to 3.55 × 1019 cm-3 and a significant decrease in electrical resistivity. The lowest resistivity obtained was 0.13 Ωcm for a Cu concentration of 18.5%. Preferential orientation of (1 1 1) and (2 0 0) occurs during deposition.

Characterization of TiO2 Thin Films on Glass Substrate Growth Using DC Sputtering Technique

International Nuclear Information System (INIS)

Agus Santoso; Tjipto Sujitno; Sayono

2002-01-01

It has been fabricated and characterization a TiO 2 thin films deposited on glass substrate using DC sputtering technique. Fabrication of TiO 2 thin films were carried out at electrode voltage 4 kV, sputtering current 5 mA, vacuum pressure 5 x 10 -4 torr, deposition time 150 minutes, and temperature of the substrate were varied from 150 -350 o C, while as a gas sputter was argon. The results was tested their micro structure using SEM, and crystal structure using XRD and found that the crystal structure of TiO 2 powder before deposited on glass substrate was rutile and anatase with orientation (110) and (200) for anatase and (100) and (111) rutile structure. While the crystal structure which deposited at temperature 150 o C and deposition time 2.5 hours was anatase with orientation (001) and (200). (author)

Effect of target power on the physical properties of Ti thin films prepared by DC magnetron sputtering with supported discharge

Directory of Open Access Journals (Sweden)

Kavitha A.

2017-02-01

Full Text Available The present paper describes the effect of target power on the properties of Ti thin films prepared by DC magnetron sputtering with (triode mode and without (diode mode supported discharge. The traditional diode magnetron sputtering with an addition of a hot filament has been used to sustain the discharge at a lower pressure. The effect of target power (60, 80, 100 and 120 W on the physical properties of Ti thin films has been studied in diode and triode modes. XRD studies showed that the Ti thin films prepared at a target power up to 100 W in diode mode were amorphous in nature. The Ti thin films exhibited crystalline structure at much lower target power of 80 W with a preferred orientation along (0 0 2 plane. The grain size of Ti thin films prepared in triode mode increased from 64 nm to 80 nm, whereas in diode mode, the grain size increased from 2 nm to 5 nm. EDAX analysis confirmed that the incorporation of reactive gases was lower in triode mode compared to diode mode. The electrical resistivity of Ti thin films deposited in diode mode was found to be 85 µΩ⋅cm (target power 120 W. The electrical resistivity of Ti thin films in triode mode was found to be deceased to 15.2 µΩ⋅cm (target power 120 W.

Thin Film growth and characterization of Ti doped ZnO by RF/DC magnetron sputtering

KAUST Repository

Baseer Haider, M.

2015-01-01

Thin film Ti doped ZnO (Ti-ZnO) film were grown on sapphire (0001) substrate by RF and DC magnetron sputtering. Films were grown at a substrate temperature of 250 °C with different Ti/Zn concentration. Surface chemical study of the samples was performed by X-ray photoelectron spectroscopy to determine the stoichiometry and Ti/Zn ratio for all samples. Surface morphology of the samples were studied by atomic force microscopy. X-ray diffraction was carried out to determine the crystallinity of the film. No secondary phases of TixOy was observed. We observed a slight increase in the lattice constant with the increase in Ti concentration in ZnO. No ferromagnetic signal was observed for any of the samples. However, some samples showed super-paramagnetic phase. © 2015 Materials Research Society.

Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications

International Nuclear Information System (INIS)

Shin, Beom-Ki; Lee, Tae-Il; Park, Ji-Hyeon; Park, Kang-Il; Ahn, Kyung-Jun; Park, Sung-Kee; Lee, Woong; Myoung, Jae-Min

2011-01-01

Applicability of Ga-doped ZnO (GZO) films for thin film solar cells (TFSCs) was investigated by preparing GZO films via pulsed dc magnetron sputtering (PDMS) with rotating target. The GZO films showed improved crystallinity and increasing degree of Ga doping with increasing thickness to a limit of 1000 nm. The films also fulfilled requirements for the transparent electrodes of TFSCs in terms of electrical and optical properties. Moreover, the films exhibited good texturing potential based on etching studies with diluted HCl, which yielded an improved light trapping capability without significant degradation in electrical propreties. It is therefore suggested that the surface-textured GZO films prepared via PDMS and etching are promising candidates for indium-free transparent electrodes for TFSCs.

Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications

Science.gov (United States)

Shin, Beom-Ki; Lee, Tae-Il; Park, Ji-Hyeon; Park, Kang-Il; Ahn, Kyung-Jun; Park, Sung-Kee; Lee, Woong; Myoung, Jae-Min

2011-11-01

Applicability of Ga-doped ZnO (GZO) films for thin film solar cells (TFSCs) was investigated by preparing GZO films via pulsed dc magnetron sputtering (PDMS) with rotating target. The GZO films showed improved crystallinity and increasing degree of Ga doping with increasing thickness to a limit of 1000 nm. The films also fulfilled requirements for the transparent electrodes of TFSCs in terms of electrical and optical properties. Moreover, the films exhibited good texturing potential based on etching studies with diluted HCl, which yielded an improved light trapping capability without significant degradation in electrical propreties. It is therefore suggested that the surface-textured GZO films prepared via PDMS and etching are promising candidates for indium-free transparent electrodes for TFSCs.

Preparation of CulnS2 Thin Films on the Glass Substrate by DC Sputtering for Solar Cell Component

International Nuclear Information System (INIS)

Bambang Siswanto; Wirjoadi; Darsono

2007-01-01

The CuInS 2 alloys were deposited on glass substrate using plasma DC sputtering technique. A CuInS 2 alloy target was made from Cu, In, Se powder with impurity of 99.998%. The deposition process was done with the following process parameter variations: deposition time and substrate temperature were the range of 15 to 45 min and 150 to 300 ℃, the gas pressure was kept at 1.4x10 -1 Torr. The purpose of the research is to obtain the solar cell component of CuInS 2 thin films. The electrical and optical properties measurement has been done by four-point probe and UV-Vis. Crystal structure was analyzed using X-ray diffraction (XRD). The result shows that minimum resistance of CuInS 2 thin films is 35.7 kΩ and optical transmittance is 14.7 %. The crystal structure of CuInS 2 is oriented at (112) plane and by Touc-plot method was obtained that the band gap energy of thin films is 1.45 eV. It could be concluded that the CuInS 2 thin film can be used as a solar cell component. (author)

Correlation between structural and electrical properties of ZnO thin films

International Nuclear Information System (INIS)

Asadov, A.; Gao, W.; Li, Z.; Lee, J.; Hodgson, M.

2005-01-01

Thin ZnO films were deposited by radio frequency (r.f.) and direct current (d.c.) magnetron sputtering techniques onto glass substrates. Microstructural and electrical properties of ZnO films were studied using X-ray diffractometer (XRD), scanning electron microscope (SEM) and resistivity measurements. It was found that the size of the crystallites in the d.c. deposited films increased with increasing film thickness, while the crystallite size of r.f. deposited films remained unchanged. The d.c. deposited grains also had much stronger orientation related to the substrate than the r.f. films. XRD data indicated that the thin films with d<350 nm for r.f. and <750 nm for d.c. films have a very high degree of ZnO nonstoichiometry. This agreed well with the conductivity measurements and R(T) behaviour of the films with different resistance R. It was also found that the electrical resistivity of the samples increased exponentially with the thickness of films

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

International Nuclear Information System (INIS)

Subrahmanyam, A.; Valleti, Krishna; Joshi, Srikant V.; Sundararajan, G.

2007-01-01

Arcing is a common phenomenon in the sputtering process. Arcs and glow discharges emit electrons which may influence the physical properties of films. This article reports the properties of tantalum (Ta) thin films prepared by continuous dc magnetron sputtering in normal and arc-suppression modes. The substrate temperature was varied in the range of 300-673 K. The tantalum films were ∼1.8 μm thick and have good adherence to 316 stainless steel and single-crystal silicon substrates. The phase of the Ta thin film determines the electrical and tribological properties. The films deposited at 300 K using both methods were crystallized in a tetragonal structure (β phase) with a smooth surface (grain size of ∼10 nm) and exhibited an electrical resistivity of ∼194 μΩ cm and a hardness of ∼20 GPa. When the substrate temperature was 473 K and higher, the arc-suppression mode appears to influence the films to crystallize in the α phase with a grain size of ∼40 nm, whereas the normal power mode gave mixed phases β and α beyond 473 K, the arc-suppression mode yields larger grain sizes in the Ta thin films and the hardness decreases. These changes in the physical properties in arc-suppression mode are attributed to either the change in plasma characteristics or the energetic particle bombardment onto the substrate, or both

High-T_c SQUIDs: Noise and applications

Energy Technology Data Exchange (ETDEWEB)

Cho, Hsiao-Mei [Univ. of Houston, TX (United States)

2001-08-01

A major challenge in the design and operation of high transition temperature (T_c ) Superconducting Quantum Interference Devices (SQUIDs) is their potential to exhibit substantially higher levels of noise at low frequency f when exposed to earth’s magnetic field. To investigate this problem, we studied the noise of high-T_c SQUIDs, directly coupled magnetometers and multilayer magnetometers in both static and changing magnetic fields. The directly coupled magnetometer consists of a dc SQUID connected to a large area pickup loop in parallel. The multilayer magnetometer involves a multiturn flux transformer inductively coupled to a dc SQUID on a separate substrate. All the devices are made of thin films of the high-Tc superconductor YBa₂Cu₃O_7-δ, patterned into 4 μm linewidths. After cooling in a magnetic field, the devices showed no increase in 1/f noise for fields up to threshold values well above the earth’s magnetic field. The devices were also cooled in a magnetic field that was subsequently turned off. The 1/f noise of bare SQUIDs was unchanged for fields up to 12 μT. The addition of the flux transformer containing flux dams increased the sensitivity to magnetic field by a factor of 43 while reducing the threshold field only moderately, to 5 μT. This result implies that the multilayer magnetometer can be rotated in the earth’s magnetic field through an angle of up to 26o without increasing the low frequency noise. The results of these studies were incorporated into a 5-channel high-Tc magnetocardiography system involving two first-derivative SQUID gradiometers and three reference SQUIDs. Each planar gradiometer consists of a directly coupled SQUID magnetometer inductively coupled to the smaller coil of an asymmetric, two-loop flux transformer. The reference SQUIDs are patterned into 4 μm lines. The outputs of the five channels were subtracted in software to form a second-derivative gradiometer. Its

High magnetic field properties of Fe-pnictide thin films

Energy Technology Data Exchange (ETDEWEB)

Kurth, Fritz

2015-11-20

The recent discovery of high-temperature superconductivity in Fe-based materials triggered worldwide efforts to investigate their fundamental properties. Despite a lot of similarities to cuprates and MgB{sub 2}, important differences like near isotropic behaviour in contrast to cuprates and the peculiar pairing symmetry of the order parameter (OP) have been reported. The OP symmetry of Fe-based superconductors (FBS) was theoretically predicted to be of so-called s± state prior to various experimental works. Still, most of the experimental results favour the s± scenario; however, definitive evidence has not yet been reported. Although no clear understanding of the superconducting mechanisms yet exists, potential applications such as high-field magnets and Josephson devices have been explored. Indeed, a lot of reports about FBS tapes, wires, and even SQUIDs have been published to this date. In this thesis, the feasibility of high-field magnet applications of FBS is addressed by studying their transport properties, involving doped BaFe{sub 2}As{sub 2} (Ba-122) and LnFeAs(O,F) [Ln=Sm and Nd]. Particularly, it is important to study physical properties in a sample form (i.e. thin films) that is close to the conditions found in applications. However, the realisation of epitaxial FBS thin films is not an easy undertaking. Recent success in growing epitaxial FBS thin films opens a new avenue to delve into transport critical current measurements. The information obtained through this research will be useful for exploring high-field magnet applications. This thesis consists of 7 chapters: Chapter 1 describes the motivation of this study, the basic background of superconductivity, and a brief summary of the thin film growth of FBS. Chapter 2 describes experimental methods employed in this study. Chapter 3 reports on the fabrication of Co-doped Ba-122 thin films on various substrates. Particular emphasis lies on the discovery of fluoride substrates to be beneficial for

On the modulation of oxygen sensitivity of In{sub 2}O{sub 3} thin films: effects of moisture and dc bias

Energy Technology Data Exchange (ETDEWEB)

Zhu, Yihao; Koley, Goutam [Department of Electrical Engineering, University of South Carolina, Columbia, SC (United States)

2014-11-15

Oxygen sensing characteristics of In{sub 2}O{sub 3} thin film at room temperature have been investigated through conductivity measurements using interdigitated metal finger patterned devices. We observed that the O{sub 2} sensitivity gets affected very significantly in presence of moisture, as well as with applied dc bias. The O{sub 2} sensitivity was found to increase several times in moist ambient compared to dry ambient condition. Higher dc bias also dramatically improved the sensitivity, which varied more than two orders of magnitude as the dc bias was increased from 0.5 to 10 V. We propose that the observed increase in sensitivity in presence of moisture is caused by enhanced surface electron density on In{sub 2}O{sub 3} thin film resulting from the donation of electrons caused by the chemisorbed water molecules. The adsorption of O{sub 2} molecules, which subsequently formed O{sub 2}{sup -} ions, leads to chemical gating of the sensor devices, which under larger dc bias produced a higher fractional change in current leading to higher sensitivity. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

STRUCTURAL, PHOTO-FUNCTIONAL AND SEMICONDUCTOR PROPERTIES OF COPPER OXIDE THIN FILMS PREPARED BY DC REACTIVE METHOD UNDER VARIOUS THICKNESSES Anmar H. Shukur

Directory of Open Access Journals (Sweden)

Anmar H. Shukur

2018-01-01

Full Text Available Cuprous oxide (Cu2O has been formed on glass substrates by dc reactive magnetron sputtering method, whereas pure target of the solid copper was sputtered with a mixture of plasma for argon gas and oxygen gas was used to form these films. Under vacuum chamber pressure of 1.2×10-5 Pa, thin film thickness was changed from 100 nm to 300 nm while other deposition parameters were fixed. The influence of changing the thickness of thin films on the electrical and the optical properties was investigated in this study. X-ray photoelectron spectroscopy (XPS, X-ray Diffractions system XRD, Atomic Force Microscopy (AFM, hall effect measurement system, UV–VIS spectrophotometer were employed to determine the characteristic of the deposited thin films. Thin film of 200 nm has observed low resistivity of 60.63 Ω cm and direct band gap of 2.5eV. This study has demonstrated that the thickness has direct influence on electrical and optical properties.

Structural and electrical characteristics of highly textured oxidation-free Ru thin films by DC magnetron sputtering

International Nuclear Information System (INIS)

Tian, H.-Y.; Wang Yu; Chan, H.-L-W.; Choy, C.-L.; No, K.-S.

2005-01-01

Textured Ru thin films (∼120 nm) were deposited on Si and rolling-assisted biaxially textured Ni substrates by a DC magnetron sputtering technique with a two-step process. The biaxially textured pure Ni substrates with a thickness of 80 μm were fabricated by rolling followed by recrystallization. The alignments and the crystallinity of Ru films were analyzed by pole figures, as well as X-ray diffraction (θ - 2θ) analysis. The highly (0 0 2) oriented Ru films were fabricated on Si substrates, and four-fold symmetric Ru films on Ni(2 0 0) substrates. The resistivities of pure metallic Ru films were 20-80 μΩ cm for Ru on Si and 16-40 μΩ cm on Ni, respectively, which is sufficiently low to be used as a buffer layer in superconductor tapes or electrode materials in capacitor dielectrics

Study of working pressure on the optoelectrical properties of Al–Y codoped ZnO thin-film deposited using DC magnetron sputtering for solar cell applications

International Nuclear Information System (INIS)

Hsu, Feng-Hao; Wang, Na-Fu; Tsai, Yu-Zen; Chuang, Ming-Chieh; Cheng, Yu-Song; Houng, Mau-Phon

2013-01-01

Low cost transparent conductive Al–Y codoped ZnO (AZOY) thin-films were prepared on a glass substrate using a DC magnetron sputtering technique with various working pressures in the range of 5–13 mTorr. The relationship among the structural, electrical, and optical properties of sputtered AZOY films was studied as a function of working pressure. The XRD measurements show that the crystallinity of the films degraded as the working gas pressure increased. The AZOY thin-film deposited at a working pressure of 5 mTorr exhibited the lowest electrical resistivity of 4.3 × 10 −4 Ω cm, carrier mobility of 30 cm 2 /V s, highest carrier concentration of 4.9 × 10 20 cm −3 , and high transmittance in the visible region (400–800 nm) of approximately 90%. Compared with Al doped ZnO (AZO) thin-films deposited using DC or RF magnetron sputtering methods, a high carrier mobility was observed in our AZOY thin-films. This result can be used to effectively decrease the absorption of near infrared-rays in solar cell applications. The mechanisms are attributed to the larger transition energy between Ar atoms and sputtering particles and the size compensation of the dopants. Finally, the optimal quality AZOY thin-film was used as an emitter layer (or window layer) to form AZOY/n-Si heterojunction solar cells, which exhibited a stable conversion efficiency (η) of 9.4% under an AM1.5 illumination condition.

Thin Co films with tunable ferromagnetic resonance frequency

International Nuclear Information System (INIS)

Maklakov, Sergey S.; Maklakov, Sergey A.; Ryzhikov, Ilya A.; Rozanov, Konstantin N.; Osipov, Alexey V.

2012-01-01

The tailored production of thin Co films of 50 nm thick with ferromagnetic resonance frequency in a range from 2.9 to 7.3 GHz using the DC magnetron sputtering is reported. The ferromagnetic resonance frequency, coercivity, effective magnetic field and nanocrystalline structure parameters are shown to be governed by the Co deposition rate. For this investigation, FMR, VSM and TEM techniques were used. - Highlights: ► Thin Co films with FMR frequency in a range from 2.9 to 7.3 GHz are obtained. ► The films' properties are governed by the deposition rate during DC magnetron sputtering. ► FMR, VSM and TEM techniques were used during the study.

Study of working pressure on the optoelectrical properties of Al–Y codoped ZnO thin-film deposited using DC magnetron sputtering for solar cell applications

Energy Technology Data Exchange (ETDEWEB)

Hsu, Feng-Hao [Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, No. 1, Dasyue Road, East District, Tainan City 701, Taiwan (China); Wang, Na-Fu; Tsai, Yu-Zen; Chuang, Ming-Chieh; Cheng, Yu-Song [Department of Electronic Engineering, Cheng Shiu University, 840 Chengcing Road, Niaosong District, Kaohsiung City 833, Taiwan (China); Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw [Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, No. 1, Dasyue Road, East District, Tainan City 701, Taiwan (China)

2013-09-01

Low cost transparent conductive Al–Y codoped ZnO (AZOY) thin-films were prepared on a glass substrate using a DC magnetron sputtering technique with various working pressures in the range of 5–13 mTorr. The relationship among the structural, electrical, and optical properties of sputtered AZOY films was studied as a function of working pressure. The XRD measurements show that the crystallinity of the films degraded as the working gas pressure increased. The AZOY thin-film deposited at a working pressure of 5 mTorr exhibited the lowest electrical resistivity of 4.3 × 10{sup −4} Ω cm, carrier mobility of 30 cm{sup 2}/V s, highest carrier concentration of 4.9 × 10{sup 20} cm{sup −3}, and high transmittance in the visible region (400–800 nm) of approximately 90%. Compared with Al doped ZnO (AZO) thin-films deposited using DC or RF magnetron sputtering methods, a high carrier mobility was observed in our AZOY thin-films. This result can be used to effectively decrease the absorption of near infrared-rays in solar cell applications. The mechanisms are attributed to the larger transition energy between Ar atoms and sputtering particles and the size compensation of the dopants. Finally, the optimal quality AZOY thin-film was used as an emitter layer (or window layer) to form AZOY/n-Si heterojunction solar cells, which exhibited a stable conversion efficiency (η) of 9.4% under an AM1.5 illumination condition.

Structure and magnetization in CoPd thin films and nanocontacts

International Nuclear Information System (INIS)

Morgan, Caitlin; Schmalbuch, Klaus; García-Sánchez, Felipe; Schneider, Claus M.; Meyer, Carola

2013-01-01

We present results showing the structural and magnetic properties of MBE-grown extended films and nanostructured elements of various CoPd alloys. X-ray diffraction studies show that the thin films are polycrystalline, yet exhibit a strong preferential growth orientation along the (111) direction. Magnetic force microscopy and SQUID are used to gain an understanding of the magnetic behavior of the CoPd system with respect to competing anisotropy contributions, based on temperature-dependent SQUID data, collected between 4 and 300 K. The idea and potential implications of using CoPd as a contact material to achieve spin injection in carbon nanotube-based devices is discussed. - Highlights: ► In-plane magnetization of CoPd films increases with added Co content. ► Quasi single-domain nanostructures of Co 50 Pd 50 exhibit almost no OOP component. ► Nanostructures exhibit decrease in coercive field with initial temperature decrease. ► Magnetic behavior is influenced by the anti-FM oxide and magnetoelastic effect.

In Situ and Ex Situ Studies of Molybdenum Thin Films Deposited by rf and dc Magnetron Sputtering as a Back Contact for CIGS Solar Cells

Directory of Open Access Journals (Sweden)

K. Aryal

2012-01-01

Full Text Available Molybdenum thin films were deposited by rf and dc magnetron sputtering and their properties analyzed with regards to their potential application as a back contact for CIGS solar cells. It is shown that both types of films tend to transition from tensile to compressive strain when the deposition pressure increases, while the conductivity and the grain size decreas. The nucleation of the films characterized by in situ and real time spectroscopic ellipsometry shows that both films follow a Volmer-Weber growth, with a higher surface roughness and lower deposition rate for the rf deposited films. The electronic relaxation time was then extracted as a function of bulk layer thickness for rf and dc films by fitting each dielectric function to a Drude free-electron model combined with a broad Lorentz oscillator. The values were fitted to a conical growth mode and demonstrated that the rf-deposited films have already smaller grains than the dc films when the bulk layer thickness is 30 nm.

Effect of Nitrogen Content on Physical and Chemical Properties of TiN Thin Films Prepared by DC Magnetron Sputtering with Supported Discharge

Science.gov (United States)

Kavitha, A.; Kannan, R.; Gunasekhar, K. R.; Rajashabala, S.

2017-10-01

Amorphous titanium nitride (TiN) thin films have been prepared on silicon (Si) and glass substrates by direct-current (DC) reactive magnetron sputtering with a supported discharge (triode). Nitrogen gas (N2) at partial pressure of 0.3 Pa, 0.4 Pa, 0.5 Pa, and 0.6 Pa was used to prepare the TiN thin films, maintaining total pressure of argon and N2 of about 0.7 Pa. The chemical, microstructural, optical, and electrical properties of the TiN thin films were systematically studied. Presence of different phases of Ti with nitrogen (N), oxygen (O2), and carbon (C) elements was revealed by x-ray photoelectron spectroscopy characterization. Increase in the nitrogen pressure from 0.3 Pa to 0.6 Pa reduced the optical bandgap of the TiN thin film from 2.9 eV to 2.7 eV. Photoluminescence study showed that TiN thin film deposited at N2 partial pressure of 0.3 Pa exhibited three shoulder peaks at 330 nm, 335 nm, and 340 nm, which disappeared when the sample was deposited with N2 partial pressure of 0.6 Pa. Increase in the nitrogen content decreased the electrical resistivity of the TiN thin film from 3200 μΩ cm to 1800 μΩ cm. Atomic force microscopy studies of the TiN thin films deposited with N2 partial pressure of 0.6 Pa showed a uniform surface pattern associated with accumulation of fine grains. The results and advantages of this method of preparing TiN thin films are also reported.

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

Energy Technology Data Exchange (ETDEWEB)

Kumar Barik, Ullash; Srinivasan, S; Nagendra, C L; Subrahmanyam, A

2003-04-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson.

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

International Nuclear Information System (INIS)

Kumar Barik, Ullash; Srinivasan, S.; Nagendra, C.L.; Subrahmanyam, A.

2003-01-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson

Evaluation of residual stress in sputtered tantalum thin-film

Energy Technology Data Exchange (ETDEWEB)

Al-masha’al, Asa’ad, E-mail: asaad.al@ed.ac.uk; Bunting, Andrew; Cheung, Rebecca

2016-05-15

Highlights: • Tantalum thin-films have been deposited by DC magnetron sputtering system. • Thin-film stress is observed to be strongly influenced by sputtering pressure. • Transition towards the compressive stress is ascribed to the annealing at 300 °C. • Expose thin-film to air ambient or ion bombardment lead to a noticeable change in the residual stress. - Abstract: The influence of deposition conditions on the residual stress of sputtered tantalum thin-film has been evaluated in the present study. Films have been deposited by DC magnetron sputtering and curvature measurement method has been employed to calculate the residual stress of the films. Transitions of tantalum film stress from compressive to tensile state have been observed as the sputtering pressure increases. Also, the effect of annealing process at temperature range of 90–300 °C in oxygen ambient on the residual stress of the films has been studied. The results demonstrate that the residual stress of the films that have been deposited at lower sputtering pressure has become more compressive when annealed at 300 °C. Furthermore, the impact of exposure to atmospheric ambient on the tantalum film stress has been investigated by monitoring the variation of the residual stress of both annealed and unannealed films over time. The as-deposited films have been exposed to pure Argon energy bombardment and as result, a high compressive stress has been developed in the films.

Anisotropic magnetotransport in epitaxial La2/3Ca1/3MnO3 thin films grown by dc-sputtering

International Nuclear Information System (INIS)

Moran, O.; Saldarriaga, W.; Prieto, P.; Baca, E.

2005-01-01

We have conducted a comprehensive study of the in-plane/out-of-plane magnetic and magnetotransport properties on (001)-oriented La 2/3 Ca 1/3 MnO 3 films epitaxially grown on single crystal (001)-SrTiO 3 substrates by dc-sputtering at high oxygen pressure. The films grew under tensile strain imposed by the lattice mismatch with the substrate. SQUID magnetometry indicated the presence of magnetocrystalline anisotropy at temperatures below the ferromagnetic Curie temperature T C with the easy plane being the film plane. Resistance measurements in magnetic field strengths of up to 6 T, applied both normal and parallel to the film plane, evidenced a distinctive dependence of the resistivity below T C on the angle of the applied field with respect to the plane of the film. During these measurements, transport current and applied magnetic field was all along maintained perpendicular to each other. Neither low-field magnetoresistance (LFMR) nor large magnetoresistance hysteresis were observed on these samples, suggesting that the tensile strain in the first monolayers has been partially released. Additionally, by rotating the sample 360 around an axis parallel to film plane, in magnetic fields ≥2 T, a quadratic sinusoidal dependence of the magnetoresistance (MR) on the polar angle θ was observed. These results can be consistently interpreted in frame of a generalized version of the theory of anisotropic magnetoresistance in transition-metal ferromagnets. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Studies on the electrical properties of reactive DC magnetron-sputtered indium-doped silver oxide thin films: The role of oxygen

Energy Technology Data Exchange (ETDEWEB)

Subrahmanyam, A [Semiconductor Physics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Barik, Ullash Kumar [Semiconductor Physics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India)

2007-03-15

Indium ({approx}10 at.%)-doped silver oxide (AIO) thin films have been prepared on glass substrates at room temperature (300 K) by reactive DC magnetron sputtering technique using an alloy target made of pure (99.99%) silver and indium (90:10 at.%) metals. The oxygen flow rates have been varied in the range 0.00-3.44 sccm during sputtering. The X-ray diffraction data on these indium-doped silver oxide films show polycrystalline nature. With increasing oxygen flow rate, the carrier concentration, the Hall mobility and the electron mean free path decrease. These films show a very low positive temperature coefficient of resistivity {approx}3.40x10{sup -8} ohm-cm/K. The work function values for these films (measured by Kelvin probe technique) are in the range 4.81-5.07 eV. The high electrical resistivity indicate that the films are in the island state (size effects). Calculations of the partial ionic charge (by Sanderson's theory) show that indium doping in silver oxide thin films enhance the ionicity.

Studies on the electrical properties of reactive DC magnetron-sputtered indium-doped silver oxide thin films: The role of oxygen

International Nuclear Information System (INIS)

Subrahmanyam, A.; Barik, Ullash Kumar

2007-01-01

Indium (∼10 at.%)-doped silver oxide (AIO) thin films have been prepared on glass substrates at room temperature (300 K) by reactive DC magnetron sputtering technique using an alloy target made of pure (99.99%) silver and indium (90:10 at.%) metals. The oxygen flow rates have been varied in the range 0.00-3.44 sccm during sputtering. The X-ray diffraction data on these indium-doped silver oxide films show polycrystalline nature. With increasing oxygen flow rate, the carrier concentration, the Hall mobility and the electron mean free path decrease. These films show a very low positive temperature coefficient of resistivity ∼3.40x10 -8 ohm-cm/K. The work function values for these films (measured by Kelvin probe technique) are in the range 4.81-5.07 eV. The high electrical resistivity indicate that the films are in the island state (size effects). Calculations of the partial ionic charge (by Sanderson's theory) show that indium doping in silver oxide thin films enhance the ionicity

Morphology, structure, and electrical properties of YBa2Cu3Ox thin films on tilted NdGaO3 substrates, deposited by DC-sputtering

International Nuclear Information System (INIS)

Mozhaev, Peter B.; Kotelyanskii, Iosif M.; Luzanov, Valery A.; Mozhaeva, Julia E.; Donchev, Todor; Mateev, Emil; Nurgaliev, Timur; Bdikin, Igor K.; Narymbetov, Bakhyt Zh.

2005-01-01

Thin YBa 2 Cu 3 O x (YBCO) films were deposited using DC-sputtering technique on NdGaO 3 substrates, tilted from (1 1 0) orientation by 0-26 deg . The structure and surface quality of the substrates were carefully characterized to obtain reliable results of thin films deposition. Structural, morphological and electrical properties of the YBCO thin films show three different ranges of inclination angle: vicinal, intermediate and high. In the vicinal range the properties of the film are generally the same as of the standard films deposited on (1 1 0) NdGaO 3 substrate. An increase of the inclination angle to the intermediate range results in a significant improvement of morphology and structural quality of the film. Best electrical parameters are measured for the films of the intermediate range also. Probable reason for such behavior is simultaneous and regular seeding of the film in the joints of facets on the substrate surface. Further increase of inclination angle leads to step bunching and oxygen out-diffusion, destroying both structural and electrical perfection of the tilted-axes YBCO film

Multichannel DC SQUID sensor array for biomagnetic applications

International Nuclear Information System (INIS)

Hoenig, H.E.; Daalmans, G.M.; Bar, L.; Bommel, F.; Paulus, A.; Uhl, D.; Weisse, H.J.; Schneider, S.; Seifert, H.; Reichenberger, H.; Abraham-Fuchs, K.

1991-01-01

This paper reports on a biomagnetic multichannel system for medical diagnosis of brain and heart KRENIKON has been developed. 37 axial 2st order gradiometers - manufactured as flexible superconducting printed circuits - are arranged in a circular flat array of 19 cm diameter. Additionally, 3 orthogonal magnetometers are provided. The DC SQUIDs are fabricated in all-Nb technology, ten on a chip. The sensor system is operated in a shielded room with two layers of soft magnetic material and one layer of Al. The every day noise level is 10 fT/Hz 1/2 at frequencies above 10 Hz. Within 2 years of operation in a normal urban surrounding, useful clinical applications have been demonstrated (e.g. for epilepsy and heart arrhythmias)

Nanocrystalline Pd:NiFe2O4 thin films: A selective ethanol gas sensor

Science.gov (United States)

Rao, Pratibha; Godbole, R. V.; Bhagwat, Sunita

2016-10-01

In this work, Pd:NiFe2O4 thin films were investigated for the detection of reducing gases. These films were fabricated using spray pyrolysis technique and characterized using X-ray diffraction (XRD) to confirm the crystal structure. The surface morphology was studied using scanning electron microscopy (SEM). Magnetization measurements were carried out using SQUID VSM, which shows ferrimagnetic behavior of the samples. These thin film sensors were tested against methanol, ethanol, hydrogen sulfide and liquid petroleum gas, where they were found to be more selective to ethanol. The fabricated thin film sensors exhibited linear response signal for all the gases with concentrations up to 5 w/o Pd. Reduction in optimum operating temperature and enhancement in response was also observed. Pd:NiFe2O4 thin films exhibited faster response and recovery characteristic. These sensors have potential for industrial applications because of their long-term stability, low power requirement and low production cost.

Structure and magnetization in CoPd thin films and nanocontacts

Energy Technology Data Exchange (ETDEWEB)

Morgan, Caitlin, E-mail: c.morgan@fz-juelich.de [Peter Gruenberg Institut, Forschungszentrum Juelich (Germany); JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany); Schmalbuch, Klaus [JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany); Physikalisches Institut, RWTH Aachen University, Otto-Blumenthal-Strasse, 52074 Aachen (Germany); Garcia-Sanchez, Felipe [Peter Gruenberg Institut, Forschungszentrum Juelich (Germany); JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany); Schneider, Claus M. [Peter Gruenberg Institut, Forschungszentrum Juelich (Germany); JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany); Fakultaet f. Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universitaet Duisburg-Essen, D-47048 Duisburg (Germany); Meyer, Carola [Peter Gruenberg Institut, Forschungszentrum Juelich (Germany); JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany)

2013-01-15

We present results showing the structural and magnetic properties of MBE-grown extended films and nanostructured elements of various CoPd alloys. X-ray diffraction studies show that the thin films are polycrystalline, yet exhibit a strong preferential growth orientation along the (111) direction. Magnetic force microscopy and SQUID are used to gain an understanding of the magnetic behavior of the CoPd system with respect to competing anisotropy contributions, based on temperature-dependent SQUID data, collected between 4 and 300 K. The idea and potential implications of using CoPd as a contact material to achieve spin injection in carbon nanotube-based devices is discussed. - Highlights: Black-Right-Pointing-Pointer In-plane magnetization of CoPd films increases with added Co content. Black-Right-Pointing-Pointer Quasi single-domain nanostructures of Co{sub 50}Pd{sub 50} exhibit almost no OOP component. Black-Right-Pointing-Pointer Nanostructures exhibit decrease in coercive field with initial temperature decrease. Black-Right-Pointing-Pointer Magnetic behavior is influenced by the anti-FM oxide and magnetoelastic effect.

Low noise SQUIDS

International Nuclear Information System (INIS)

Waal, V.J. de.

1983-01-01

The design, fabrication and limitations of very sensitive SQUID magnetometers are described. The SQUID magnetometer is based on the Josephson effect. A very low-noise niobium SQUID is described. It is fabricated with ultra-small niobium junctions with an overlapping area smaller than 1 μm 2 . The photolithographic technique developed for its fabrication, is described. Also an integrated system with a SQUID and a first-order gradiometer on a single substrate is presented. Calculations of the resolution of a dc SQUID containing ideal Josephson junctions according to the RSJ model are presented including a parasitic capacitance. The usefulness of the fabricated SQUIDS as well as some remarks on their performance is considered. (Auth.)

Ion-conductivity of thin film Li-Borate glasses

International Nuclear Information System (INIS)

Abouzari, M.R.S.

2007-01-01

In this thesis, the specific conductivity of ion-sputtered lithium borate thin films is studied. To this end, lithium borate glasses of the composition yLi 2 O.(1-y)B 2 O 3 with y=0.15, 0.20, 0.25, and 0.35 were produced as sputter targets. Films with thicknesses between 7 nm and 700 nm are deposited on silicon substrate between two AlLi electrodes. Conductivity spectra have been taken over a frequency range of 5 Hz to 2 MHz. The measurements were performed at different temperatures between 40 C and 350 C depending on the thickness and the composition of the films. The following results are derived by studying the conductivities of the films: i) The specific dc conductivity of layers with thicknesses larger than 150 nm is independent of their thicknesses; we call these layers 'thick films' and consider their conductivity as the 'base conductivity'. ii) The specific dc conductivity of layers with thicknesses smaller than 150 nm, called 'thin films', depends on the layer thickness. A nontrivial enhancement of the specific dc conductivity about three orders of magnitude for y=0.15, 0.2, and 0.25 is observed. iii) The base conductivity depends on y and at 120 C it varies between 4 x 10 -10 Ω -1 cm -1 and 2.5 x 10 -6 Ω -1 cm -1 when y varies between 0.15 and 0.35, whereas the maximum value of the specific dc conductivity of extremely thin films (with a thickness of some nanometre) seems to be independent of y and equals to the specific dc conductivity of layers with y= 0.35. Furthermore, we found in this work a physical interpretation of the so-called 'Constant Phase Element' (CPE) which is widely used in equivalent circuits for ionic conductors. This element describes correctly the depressed impedance semicircles observed in impedance spectroscopy. So far, this effect is sometimes attributed to the surface roughness. We have shown not only the invalidity of this approach, but we have also found that the depression arises from the nature of ionic motions. The model

Dynamics of d-wave YBa{sub 2}Cu{sub 3}O{sub 7-x} dc SQUIDs

Energy Technology Data Exchange (ETDEWEB)

Bauch, T [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Cedergren, K [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Johansson, J [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden); Rotoli, G [Dipartimento di Ingeneria Meccanica, Energetica e Gestionale, Universita of L' Aquila, Localita Moneluco, L' Aquila (Italy); Tafuri, F [Dipartimento Ingeneria dell' Informatione, INFM, Seconda Universita di Napoli, Aversa (Italy); Lombardi, F [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Goeteborg (Sweden)

2007-02-15

The predominant d-wave pairing symmetry in high temperature superconductors leads to an unconventional current-phase relation in Josephson junctions. This circumstance may induce new effects in the dynamics of dc SQUIDs. In this contribution we report on the measurements of the dependence of the SQUID Josephson current on the external magnetic field taken at very low temperatures, down to 20 mK. Different grain boundaries have been fabricated by using the biepitaxial and the bicrystal technique. Some of the effects which are induced by a nonsinusoidal current-phase relation can be clearly identified in the dynamics of the SQUIDs. The experimental data are also compared with theoretical simulations taking into account the inductance of the loop. The data show that, in specific conditions, a non-negligible inductance of the loop can induce effects similar to an unconventional current-phase relation, with a pronounced second harmonic sin(2{psi}) term. This fact has to be taken into account when designing d-wave SQUIDs for quantum circuitry.

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

Science.gov (United States)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-10-01

A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 °C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 × 10-4 Ω cm with the carrier concentration of 1.65 × 1021 cm-3 and Hall mobility of 11.3 cm2/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Room temperature growth of nanocrystalline anatase TiO2 thin films by dc magnetron sputtering

International Nuclear Information System (INIS)

Singh, Preetam; Kaur, Davinder

2010-01-01

We report, the structural and optical properties of nanocrystalline anatase TiO 2 thin films grown on glass substrate by dc magnetron sputtering at room temperature. The influence of sputtering power and pressure over crystallinity and surface morphology of the films were investigated. It was observed that increase in sputtering power activates the TiO 2 film growth from relative lower surface free energy to higher surface free energy. XRD pattern revealed the change in preferred orientation from (1 0 1) to (0 0 4) with increase in sputtering power, which is accounted for different surface energy associated with different planes. Microstructure of the films also changes from cauliflower type to columnar type structures with increase in sputtering power. FESEM images of films grown at low pressure and low sputtering power showed typical cauliflower like structure. The optical measurement revealed the systematic variation of the optical constants with deposition parameters. The films are highly transparent with transmission higher than 90% with sharp ultraviolet cut off. The transmittance of these films was found to be influenced by the surface roughness and film thickness. The optical band gap was found to decrease with increase in the sputtering power and pressure. The refractive index of the films was found to vary in the range of 2.50-2.24 with increase in sputtering pressure or sputtering power, resulting in the possibility of producing TiO 2 films for device applications with different refractive index, by changing the deposition parameters.

Magneto-optical and magnetic properties in a Co/Pd multilayered thin film

Energy Technology Data Exchange (ETDEWEB)

Nwokoye, Chidubem A. [Institute for Magnetics Research, Department of Electrical and Computer Engineering, The George Washington University, DC 20052 (United States); Naval Air Systems Command, Avionics, Sensors and E*Warfare Department, Patuxent River, MD 20670 (United States); Bennett, Lawrence H., E-mail: lbennett@gwu.edu [Institute for Magnetics Research, Department of Electrical and Computer Engineering, The George Washington University, DC 20052 (United States); Della Torre, Edward, E-mail: edt@gwu.edu [Institute for Magnetics Research, Department of Electrical and Computer Engineering, The George Washington University, DC 20052 (United States); Ghahremani, Mohammadreza [Institute for Magnetics Research, Department of Electrical and Computer Engineering, The George Washington University, DC 20052 (United States); Narducci, Frank A. [Naval Air Systems Command, Avionics, Sensors and E*Warfare Department, Patuxent River, MD 20670 (United States)

2017-01-01

The paper describes investigation of ferromagnetism at low temperatures. We explored the magneto-optical properties, influenced by photon–magnon interactions, of a ferromagnetic Co/Pd multilayered thin film below and above the magnon Bose–Einstein Condensation (BEC) temperature. Analyses of SQUID and MOKE low temperature experimental results reveal a noticeable phase transition in both magnetic and magneto-optical properties of the material at the BEC temperature. - Highlights: • The results show the effect of a non-zero chemical potential on the magnetization. • The MOKE and SQUID results show a phase transition point at the same temperature. • Magnon BEC is a major influence of the observed phase transition temperature.

Magnetic Property in Large Array Niobium Antidot Thin Films

Science.gov (United States)

Tinghui, Chen; Hsiang-Hsi, Kung; Wei-Li, Lee; Institute of Physics, Academia Sinica, Taipei, Taiwan Team

2014-03-01

In a superconducting ring, the total flux inside the ring is required to be an integer number of the flux quanta. Therefore, a supercurrent current can appear within the ring in order to satisfy this quantization rule, which gives rise to certain magnetic response. By using a special monolayer polymer/nanosphere hybrid we developed previously, we fabricated a series of superconducting niobium antidot thin films with different antidot diameters. The antidots form well-ordered triangular lattice with a lattice spacing about 200 nm and extend over an area larger than 1 cm2, which enables magnetic detections simply by a SQUID magnetometer. We observed magnetization oscillation with external magnetic field due to the supercurrent screening effect, where different features for large and small antidot thin films were found. Detailed size and temperature dependencies of the magnetization in niobium antidot nanostructures will be presented.

The bases for the development of high-temperature integrated SQUID-systems

International Nuclear Information System (INIS)

Polushkin, V.N.

1992-01-01

The current state of high-T c superconducting thin-film Josephson junctions and SQUIDs developing is reviewed. The prospects of application of new devices in supersensitive measurement apparatus are analyzed. It is shown that high T c SQUIDs are able seriously to influence further development of information and measurement engineering as on their base the series of microelectronic elements and devices of new generation can be built. 55 refs.; 7 figs.; 2 tabs

Electrical and optical properties of reactive dc magnetron sputtered silver-doped indium oxide thin films: role of oxygen

International Nuclear Information System (INIS)

Subrahmanyam, A.; Barik, U.K.

2006-01-01

Silver-doped indium oxide thin films have been prepared on glass and quartz substrates at room temperature (300 K) by a reactive dc magnetron sputtering technique using an alloy target of pure indium and silver (80:20 at. %). During sputtering, the oxygen flow rates are varied in the range 0.00-2.86 sccm keeping the magnetron power constant at 40 W. The resistivity of these films is in the range 10 0 -10 -3 Ωcm and they show a negative temperature coefficient of resistivity. The films exhibit p-type conductivity at an oxygen flow rate of 1.71 sccm. The work function of these silver-indium oxide films has been measured by a Kelvin probe technique. The refractive index of the films (at 632.8 nm) varies in the range 1.13-1.20. Silver doping in indium oxide narrows the band gap of indium oxide (3.75 eV). (orig.)

Electrical and optical properties of reactive dc magnetron sputtered silver-doped indium oxide thin films: role of oxygen

Energy Technology Data Exchange (ETDEWEB)

Subrahmanyam, A; Barik, U K [Indian Institute of Technology Madras, Semiconductor Physics Laboratory, Department of Physics, Chennai (India)

2006-07-15

Silver-doped indium oxide thin films have been prepared on glass and quartz substrates at room temperature (300 K) by a reactive dc magnetron sputtering technique using an alloy target of pure indium and silver (80:20 at. %). During sputtering, the oxygen flow rates are varied in the range 0.00-2.86 sccm keeping the magnetron power constant at 40 W. The resistivity of these films is in the range 10{sup 0}-10{sup -3} {omega}cm and they show a negative temperature coefficient of resistivity. The films exhibit p-type conductivity at an oxygen flow rate of 1.71 sccm. The work function of these silver-indium oxide films has been measured by a Kelvin probe technique. The refractive index of the films (at 632.8 nm) varies in the range 1.13-1.20. Silver doping in indium oxide narrows the band gap of indium oxide (3.75 eV). (orig.)

Effect of working pressure on corrosion behavior of nitrogen doped diamond-like carbon thin films deposited by DC magnetron sputtering.

Science.gov (United States)

Khun, N W; Liu, E

2011-06-01

Nitrogen doped diamond-like carbon thin films were deposited on highly conductive p-silicon(100) substrates using a DC magnetron sputtering deposition system by varying working pressure in the deposition chamber. The bonding structure, adhesion strength, surface roughness and corrosion behavior of the films were investigated by using X-ray photoelectron spectroscopy, micro-Raman spectroscopy, micro-scratch test, atomic force microscopy and potentiodynamic polarization test. A 0.6 M NaCl electrolytic solution was used for the corrosion tests. The optimum corrosion resistance of the films was found at a working pressure of 7 mTorr at which a good balance between the kinetics of the sputtered ions and the surface mobility of the adatoms promoted a microstructure of the films with fewer porosities.

Electron beam induced coloration and luminescence in layered structure of WO3 thin films grown by pulsed dc magnetron sputtering

International Nuclear Information System (INIS)

Karuppasamy, A.; Subrahmanyam, A.

2007-01-01

Tungsten oxide thin films have been deposited by pulsed dc magnetron sputtering of tungsten in argon and oxygen atmosphere. The as-deposited WO 3 film is amorphous, highly transparent, and shows a layered structure along the edges. In addition, the optical properties of the as-deposited film show a steplike behavior of extinction coefficient. However, the electron beam irradiation (3.0 keV) of the as-deposited films results in crystallization, coloration (deep blue), and luminescence (intense red emission). The above changes in physical properties are attributed to the extraction of oxygen atoms from the sample and the structural modifications induced by electron bombardment. The present method of coloration and luminescence has a potential for fabricating high-density optical data storage device

Zinc Vacancy-Induced Room-Temperature Ferromagnetism in Undoped ZnO Thin Films

Directory of Open Access Journals (Sweden)

Hongtao Ren

2012-01-01

Full Text Available Undoped ZnO thin films are prepared by polymer-assisted deposition (PAD and treated by postannealing at different temperatures in oxygen or forming gases (95%  Ar+5% H2. All the samples exhibit ferromagnetism at room temperature (RT. SQUID and positron annihilation measurements show that post-annealing treatments greatly enhance the magnetizations in undoped ZnO samples, and there is a positive correlation between the magnetization and zinc vacancies in the ZnO thin films. XPS measurements indicate that annealing also induces oxygen vacancies that have no direct relationship with ferromagnetism. Further analysis of the results suggests that the ferromagnetism in undoped ZnO is induced by Zn vacancies.

Rutile TiO2 thin films grown by reactive high power impulse magnetron sputtering

International Nuclear Information System (INIS)

Agnarsson, B.; Magnus, F.; Tryggvason, T.K.; Ingason, A.S.; Leosson, K.; Olafsson, S.; Gudmundsson, J.T.

2013-01-01

Thin TiO 2 films were grown on Si(001) substrates by reactive dc magnetron sputtering (dcMS) and high power impulse magnetron sputtering (HiPIMS) at temperatures ranging from 300 to 700 °C. Optical and structural properties of films were compared both before and after post-annealing using scanning electron microscopy, low angle X-ray reflection (XRR), grazing incidence X-ray diffractometry and spectroscopic ellipsometry. Both dcMS- and HiPIMS-grown films reveal polycrystalline rutile TiO 2 , even prior to post-annealing. The HiPIMS-grown films exhibit significantly larger grains compared to that of dcMC-grown films, approaching 100% of the film thickness for films grown at 700 °C. In addition, the XRR surface roughness of HiPIMS-grown films was significantly lower than that of dcMS-grown films over the whole temperature range 300–700 °C. Dispersion curves could only be obtained for the HiPIMS-grown films, which were shown to have a refractive index in the range of 2.7–2.85 at 500 nm. The results show that thin, rutile TiO 2 films, with high refractive index, can be obtained by HiPIMS at relatively low growth temperatures, without post-annealing. Furthermore, these films are smoother and show better optical characteristics than their dcMS-grown counterparts. - Highlights: • We demonstrate growth of rutile TiO 2 on Si (111) by high power impulse magnetron sputtering. • The films exhibit significantly larger grains than dc magnetron sputtered films • TiO 2 films with high refractive index are obtained without post-growth annealing

Synthesis of Ag-Cu-Pd alloy thin films by DC-magnetron sputtering: Case study on microstructures and optical properties

Science.gov (United States)

Rezaee, Sahar; Ghobadi, Nader

2018-06-01

The present study aims to investigate optical properties of Ag-Cu-Pd alloy thin films synthesized by DC-magnetron sputtering method. The thin films are deposited on the glass and silicon substrates using Argon gas and Ag-Cu-Pd target. XRD analysis confirms the successful growth of Ag, Cu, and Pd NPs with FCC crystalline structure. Moreover, UV-visible absorption spectroscopy is applied to determine optical properties of the prepared samples which are affected by changes in surface morphology. The existence of single surface plasmon resonance (SPR) peak near 350 nm proves the formation of silver nanoparticles with a slight red shift through increasing deposition time. Ineffective thickness method (ITM) and Derivation of ineffective thickness method (DITM) are applied to extract optical band gap and transition type via absorption spectrum. SEM and AFM analyses show the distribution of near-spherical nanoparticles covering the surface of thin films. Furthermore, thickness variation affects the grain size. In addition, TEM image reveals the uniform size distribution of nanoparticles with an average particle size of about 15 nm. The findings show that increasing grain size and crystallite order along with the decrease of structural defect and disorders decrease optical band gap from 3.86 eV to 2.58 eV.

Thermal activation and macroscopic quantum tunneling in a DC SQUID

International Nuclear Information System (INIS)

Sharifi, F.; Gavilano, J.L.; VanHarlingen, D.J.

1989-01-01

The authors report measurements of the transition rate from metastable minima in the two-dimensional 1 of a dc SQUID as a function of applied flux temperature. The authors observe a crossover from energy-activated escape to macroscopic quantum tunneling at a critical temperature. The macroscopic quantum tunneling rate is substantially reduced by damping, and also broadens the crossover region. Most interestingly, the authors observe thermal rates that are suppressed from those predicted by the two-dimensional thermal activation model. The authors discuss possible explanations for this based on the interaction of the macroscopic degree of freedom in the device and energy level effects

Ion-conductivity of thin film Li-Borate glasses

Energy Technology Data Exchange (ETDEWEB)

Abouzari, M.R.S.

2007-12-17

In this thesis, the specific conductivity of ion-sputtered lithium borate thin films is studied. To this end, lithium borate glasses of the composition yLi{sub 2}O.(1-y)B{sub 2}O{sub 3} with y=0.15, 0.20, 0.25, and 0.35 were produced as sputter targets. Films with thicknesses between 7 nm and 700 nm are deposited on silicon substrate between two AlLi electrodes. Conductivity spectra have been taken over a frequency range of 5 Hz to 2 MHz. The measurements were performed at different temperatures between 40 C and 350 C depending on the thickness and the composition of the films. The following results are derived by studying the conductivities of the films: i) The specific dc conductivity of layers with thicknesses larger than 150 nm is independent of their thicknesses; we call these layers 'thick films' and consider their conductivity as the 'base conductivity'. ii) The specific dc conductivity of layers with thicknesses smaller than 150 nm, called 'thin films', depends on the layer thickness. A nontrivial enhancement of the specific dc conductivity about three orders of magnitude for y=0.15, 0.2, and 0.25 is observed. iii) The base conductivity depends on y and at 120 C it varies between 4 x 10{sup -10} {omega}{sup -1}cm{sup -1} and 2.5 x 10{sup -6} {omega}{sup -1}cm{sup -1} when y varies between 0.15 and 0.35, whereas the maximum value of the specific dc conductivity of extremely thin films (with a thickness of some nanometre) seems to be independent of y and equals to the specific dc conductivity of layers with y= 0.35. Furthermore, we found in this work a physical interpretation of the so-called 'Constant Phase Element' (CPE) which is widely used in equivalent circuits for ionic conductors. This element describes correctly the depressed impedance semicircles observed in impedance spectroscopy. So far, this effect is sometimes attributed to the surface roughness. We have shown not only the invalidity of this approach, but

Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

Science.gov (United States)

Bechstein, S.; Petsche, F.; Scheiner, M.; Drung, D.; Thiel, F.; Schnabel, A.; Schurig, Th

2006-06-01

Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-Tc dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm × 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm × 4 cm × 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

International Nuclear Information System (INIS)

Bechstein, S; Petsche, F; Scheiner, M; Drung, D; Thiel, F; Schnabel, A; Schurig, Th

2006-01-01

Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/√Hz was specially designed for a 304-channel low-T c dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm x 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm x 4 cm x 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented

Digitally controlled high-performance dc SQUID readout electronics for a 304-channel vector magnetometer

Energy Technology Data Exchange (ETDEWEB)

Bechstein, S [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Petsche, F [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Scheiner, M [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Drung, D [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Thiel, F [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Schnabel, A [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Schurig, Th [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)

2006-06-01

Recently, we have developed a family of dc superconducting quantum interference device (SQUID) readout electronics for several applications. These electronics comprise a low-noise preamplifier followed by an integrator, and an analog SQUID bias circuit. A highly-compact low-power version with a flux-locked loop bandwidth of 0.3 MHz and a white noise level of 1 nV/{radical}Hz was specially designed for a 304-channel low-T{sub c} dc SQUID vector magnetometer, intended to operate in the new Berlin Magnetically Shielded Room (BMSR-2). In order to minimize the space needed to mount the electronics on top of the dewar and to minimize the power consumption, we have integrated four electronics channels on one 3 cm x 10 cm sized board. Furthermore we embedded the analog components of these four channels into a digitally controlled system including an in-system programmable microcontroller. Four of these integrated boards were combined to one module with a size of 4 cm x 4 cm x 16 cm. 19 of these modules were implemented, resulting in a total power consumption of about 61 W. To initialize the 304 channels and to service the system we have developed software tools running on a laptop computer. By means of these software tools the microcontrollers are fed with all required data such as the working points, the characteristic parameters of the sensors (noise, voltage swing), or the sensor position inside of the vector magnetometer system. In this paper, the developed electronics including the software tools are described, and first results are presented.

Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

Energy Technology Data Exchange (ETDEWEB)

Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

2016-12-15

Magnetoelectric M-type hexaferrite thin films (SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10{sup −9} s m{sup −1} in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} thin films.

Electrical and optical properties of indium tin oxide thin films deposited on unheated substrates by d.c. reactive sputtering

International Nuclear Information System (INIS)

Karasawa, T.; Miyata, Y.

1993-01-01

Transparent conducting thin films of indium tin oxide (ITO) have been deposited by d.c. reactive planar magnetron sputtering by using metal In-Sn alloy target in an Ar-O 2 gas mixture. The study demonstrates that the deposition on unheated substrates achieved sheet resistance of as low as about 50-60 Ω/□ (or a resistivity of about 7 x 10 -4 Ω cm), and visible transmission of about 90% for a wavelength of 420 nm. The effects of heat treatment at 450 C in air depends on the deposition conditions of the as-deposited ITO films. Although annealing improves the properties of as-deposited ITO films which were deposited with non-optimum conditions, the optimized condition for the formation of the film in the as-deposited state is essential to obtain a high quality transparent conducting coating. (orig.)

Properties of electropolymerised polypyrrole thin film on silver

Science.gov (United States)

Jamadade, Shivaji A.; Puri, Vijaya

2009-07-01

This paper reports the properties of electropolymerised polypyrrole thin film on silver. The transmission, reflection, conductivity and dielectric behavior of polypyrrole coated silver has been studied in the 8-12 GHz frequency range of the electromagnetic spectrum. The polypyrrole thin film makes silver a better conductor for microwaves. The microwave conductivity is larger than the DC conductivity by many orders of magnitude. The real and imaginary part of dielectric constant increases in magnitude with increasing doping level and also it decreases in magnitude with increasing frequency.

Thin Film Microbatteries

International Nuclear Information System (INIS)

Dudney, Nancy J.

2008-01-01

Thin film batteries are built layer by layer by vapor deposition. The resulting battery is formed of parallel plates, much as an ordinary battery construction, just much thinner. The figure (Fig. 1) shows an example of a thin film battery layout where films are deposited symmetrically onto both sides of a supporting substrate. The full stack of films is only 10 to 15 (micro)m thick, but including the support at least doubles the overall battery thickness. When the support is thin, the entire battery can be flexible. At least six companies have commercialized or are very close to commercializing such all-solid-state thin film batteries and market research predicts a growing market and a variety of applications including sensors, RFID tags, and smarter cards. In principle with a large deposition system, a thin film battery might cover a square meter, but in practice, most development is targeting individual cells with active areas less than 25 cm 2 . For very small battery areas, 2 , microfabrication processes have been developed. Typically the assembled batteries have capacities from 0.1 to 5 mAh. The operation of a thin film battery is depicted in the schematic diagram (Fig. 2). Very simply, when the battery is allowed to discharge, a Li + ion migrates from the anode to the cathode film by diffusing through the solid electrolyte. When the anode and cathode reactions are reversible, as for an intercalation compound or alloy, the battery can be recharged by reversing the current. The difference in the electrochemical potential of the lithium determines the cell voltage. Most of the thin films used in current commercial variations of this thin film battery are deposited in vacuum chambers by RF and DC magnetron sputtering and by thermal evaporation onto unheated substrates. In addition, many publications report exploring a variety of other physical and chemical vapor deposition processes, such as pulsed laser deposition, electron cyclotron resonance sputtering, and

The use of (double) relaxation oscillation SQUIDs as a sensor

NARCIS (Netherlands)

van Duuren, M.J.; Brons, G.C.S.; Kattouw, H.; Flokstra, Jakob; Rogalla, Horst

1997-01-01

Relaxation Oscillation SQUIDs (ROSs) and Double Relaxation Oscillation SQUIDs (DROSs) are based on relaxation oscillations that are induced in hysteretic dc SQUIDs by an external L-R shunt. The relaxation frequency of a ROS varies with the applied flux Φ, whereas the output of a DROS is a dc

Direct current magnetron sputter-deposited ZnO thin films

International Nuclear Information System (INIS)

Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong; Knipp, Dietmar

2011-01-01

Zinc oxide (ZnO) is a very promising electronic material for emerging transparent large-area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 150 nm to 750 nm were deposited on glass substrates. The deposition pressure and the substrate temperature were varied from 12 mTorr to 25 mTorr, and from room temperature to 450 deg. C, respectively. The influence of the film thickness, deposition pressure and the substrate temperature on structural and optical properties of the ZnO films was investigated using atomic force microscopy (AFM) and ultraviolet-visible (UV-Vis) spectrometer. The experimental results reveal that the film thickness, deposition pressure and the substrate temperature play significant role in the structural formation and the optical properties of the deposited ZnO thin films.

Optical and electrical properties of chemical bath deposited cobalt sulphide thin films

Energy Technology Data Exchange (ETDEWEB)

Govindasamy, Geetha [R& D Centre, Bharathiar University, Coimbatore (India); Murugasen, Priya, E-mail: priyamurugasen15@gmail.com [Department of Physics, Saveetha Engineering, Chennai, Tamil Nadu (India); Sagadevan, Suresh [Department of Physics, AMET University, Chennai, Tamil Nadu (India)

2017-01-15

Cobalt sulphide (CoS) thin films were synthesized using the Chemical Bath Deposition (CBD) technique. X-ray diffraction (XRD) analysis was used to study the structure and the crystallite size of CoS thin film. Scanning Electron Microscope (SEM) studies reveal the surface morphology of these films. The optical properties of the CoS thin films were determined using UV-Visible absorption spectrum. The optical band gap of the thin films was found to be 1.6 eV. Optical constants such as the refractive index, the extinction coefficient and the electric susceptibility were determined. The dielectric studies were carried out at different frequencies and at different temperatures for the prepared CoS thin films. In addition, the plasma energy of the valence electron, Penn gap or average energy gap, the Fermi energy and electronic polarizability of the thin films were determined. The AC electrical conductivity measurement was also carried out for the thin films. The activation energy was determined by using DC electrical conductivity measurement. (author)

Inhomogeneous strain states in sputter deposited tungsten thin films

International Nuclear Information System (INIS)

Noyan, I.C.; Shaw, T.M.; Goldsmith, C.C.

1997-01-01

The results of an x-ray diffraction study of dc-magnetron sputtered tungsten thin films are reported. It is shown that the phase transformation from the β to α W can cause multilayered single-phase films where the layers have very different stress states even if the films are in the 500 nm thickness range. copyright 1997 American Institute of Physics

Influences of the RF power ratio on the optical and electrical properties of GZO thin films by DC coupled RF magnetron sputtering at room temperature

Energy Technology Data Exchange (ETDEWEB)

Peng, Shou [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China); Yao, Tingting, E-mail: yaott0815@163.com [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China); Yang, Yong; Zhang, Kuanxiang; Jiang, Jiwen; Jin, Kewu; Li, Gang; Cao, Xin; Xu, Genbao; Wang, Yun [State Key Laboratory of Advanced Technology for Float Glass, Bengbu 233018 (China); Bengbu Design & Research Institute for Glass Industry, Bengbu 233018 (China)

2016-12-15

Ga-doped zinc oxide (GZO) thin films were deposited by closed field unbalanced DC coupled RF magnetron sputtering system at room temperature. The RF sputtering power ratio was adjusted from 0% to 100%. The crystal structure, surface morphology, transmittance and electrical resistivity of GZO films mainly influenced by RF sputtering power ratio were investigated by X-ray diffractometer, scanning electronic microscope, ultraviolet-visible spectrophotometer and Hall effect measurement. The research results indicate that the increasing RF power ratio can effectively reduce the discharge voltage of system and increase the ionizing rate of particles. Meanwhile, the higher RF power ratio can increase the carrier mobility in GZO thin film and improve the optical and electrical properties of GZO thin film significantly. Within the optimal discharge voltage window, the film deposits at 80% RF power ratio exhibits the lowest resistivity of 2.6×10{sup −4} Ω cm. We obtain the GZO film with the best average optical transmittance is approximately 84% in the visible wavelength. With the increasing RF power ratio, the densification of GZO film is enhanced. The densification of GZO film is decrease when the RF power ratio is 100%.

Polymer thin film as coating layer to prevent corrosion of metal/metal oxide film

Science.gov (United States)

Sarkar, Suman; Kundu, Sarathi

2018-04-01

Thin film of polymer is used as coating layer and the corrosion of metal/metal oxide layer is studied with the variation of the thickness of the coating layer. The thin layer of polystyrene is fabricated using spin coating method on copper oxide (CuO) film which is deposited on glass substrate using DC magnetron sputtering technique. Thickness of the polystyrene and the CuO layers are determined using X-ray reflectivity (XRR) technique. CuO thin films coated with the polystyrene layer are exposed to acetic acid (2.5 v/v% aqueous CH3COOH solution) environments and are subsequently analyzed using UV-Vis spectroscopy and atomic force microscopy (AFM). Surface morphology of the film before and after interaction with the acidic environment is determined using AFM. Results obtained from the XRR and UV-Vis spectroscopy confirm that the thin film of polystyrene acts as an anticorrosion coating layer and the strength of the coating depends upon the polymer layer thickness at a constant acid concentration.

Photolithographically patterened thin-film multilayer devices of YBa2Cu3O7-x

International Nuclear Information System (INIS)

Kingston, J.J.; Wellstood, F.C.; Quan, D.; Clarke, J.

1990-09-01

We have fabricated thin-film YBa 2 Cu 3 O 7-x -SrTiO 3 -YBa 2 Cu 3 O 7-x multilayer interconnect structures in which each in situ laser-deposited film is independently patterned by photolithography. In particular, we have constructed the two key components necessary for a superconducting multilayer interconnect technology, crossovers and window contacts. As a further demonstration of the technology, we have fabricated a thin-film flux transformer, suitable for use with a Superconducting QUantum Interference Device (SQUID), that includes a ten-turn input coil with 6μm linewidth. Transport measurements showed that the critical temperature was 87K and the critical current was 135 μA at 82K. 7 refs., 6 figs

Nanocrystalline Pd:NiFe2O4 thin films: A selective ethanol gas sensor

International Nuclear Information System (INIS)

Rao, Pratibha; Godbole, R.V.; Bhagwat, Sunita

2016-01-01

In this work, Pd:NiFe 2 O 4 thin films were investigated for the detection of reducing gases. These films were fabricated using spray pyrolysis technique and characterized using X-ray diffraction (XRD) to confirm the crystal structure. The surface morphology was studied using scanning electron microscopy (SEM). Magnetization measurements were carried out using SQUID VSM, which shows ferrimagnetic behavior of the samples. These thin film sensors were tested against methanol, ethanol, hydrogen sulfide and liquid petroleum gas, where they were found to be more selective to ethanol. The fabricated thin film sensors exhibited linear response signal for all the gases with concentrations up to 5 w/o Pd. Reduction in optimum operating temperature and enhancement in response was also observed. Pd:NiFe 2 O 4 thin films exhibited faster response and recovery characteristic. These sensors have potential for industrial applications because of their long-term stability, low power requirement and low production cost. - Highlights: • Ethanol gas sensors based on Pd:NiFe 2 O 4 nanoparticle thin film were fabricated. • Pd incorporation in NiFe 2 O 4 matrix inhibits grain growth. • The sensors were more selective to ethanol gas. • Sensors exhibited fast response and recovery when doped with palladium. • Pd:NiFe 2 O 4 thin film sensor displays excellent long–term stability.

Room temperature H2S gas sensing property of indium oxide thin films obtained by pulsed D.C. magnetron sputtering

International Nuclear Information System (INIS)

Nisha, R.; Madhusoodanan, K.N.; Karthikeyan, Sreejith; Hill, Arthur E.; Pilkington, Richard D.

2013-01-01

Indium oxide thin films were prepared by pulsed dc magnetron sputtering technique with no substrate heating. X-ray diffraction was used to investigate the structural properties and AFM was used to study the surface morphology gas sensing performance were conducted using a static gas sensing system. Room temperature gas sensing performance was conducted in range of 17 to 286 ppm. The sensitivity, response and recovery time of the sensor was also determined. (author)

Josephson effectss in bicrystalline Bi2Sr2CaCu2O8+δ thin films

International Nuclear Information System (INIS)

Amrein, T.

1994-08-01

A pulsed laser deposition process is developed for preparing high quality thin films of Bi 2 Sr 2 CaCu 2 O x on different substrates. Both microstructural and electrical properties of the superconducting films are well characterized, e.g. by SEM, TEM and AFM. The high reproducability of the thin film quality facilitated a detailed study of Josephson effects in bicrystalline grain boundary junctions (GBJs). Thin films are deposited on commercially available (001) SrTiO 3 bicrystalls and patterned by standard photolithography using wet-etching or Ar + -ion milling. The width of the micobridges ranges from 2 to 111 μm. The critical current densities across grain boundaries of thin film bicrystals have been measured as a function of the tilt angle Θ. For Θ=0 to 45 , the ratio of the grain boundary critical current density to the bulk critical current density decreases exponentially with increasing tilt angle. Microstructure investigations show a rough grain boundary of the superconductor (roughness 100 nm-1 μm) which is not determined by the roughness of the substrate grain boundary (1-3 nm) but by the island-plus-layer growth of the twin domains. The electrical properties are well described by the resistively shunted junction (RSJ) model. The I c R n -product reaches values of 2.2 mV at 4.2 K and 60 μV at 77 K. An optimized design for dc SQUIDs (Θ=24 ) is developed relating to the results of single GBJs. The values of the transfer function (∂V/∂Φ) run up to 74 μV/Φ o . The equivalent flux noise which is measured in a flux-locked loop mode amounts 4.5 to 25 μPhi o Hz in the white noise region for Φ≥25-50 Hz and 13 to 150 μΦ o Hz at 1 Hz. In conclusion, microstructural as well as electrical properties of bicrystalline Bi 2 Sr 2 CaCu 2 O x and YBa 2 Cu 3 O y GBJs are more or less equal. (orig.)

Nanosphere lithography applied to magnetic thin films

Science.gov (United States)

Gleason, Russell

Magnetic nanostructures have widespread applications in many areas of physics and engineering, and nanosphere lithography has recently emerged as promising tool for the fabrication of such nanostructures. The goal of this research is to explore the magnetic properties of a thin film of ferromagnetic material deposited onto a hexagonally close-packed monolayer array of polystyrene nanospheres, and how they differ from the magnetic properties of a typical flat thin film. The first portion of this research focuses on determining the optimum conditions for depositing a monolayer of nanospheres onto chemically pretreated silicon substrates (via drop-coating) and the subsequent characterization of the deposited nanosphere layer with scanning electron microscopy. Single layers of permalloy (Ni80Fe20) are then deposited on top of the nanosphere array via DC magnetron sputtering, resulting in a thin film array of magnetic nanocaps. The coercivities of the thin films are measured using a home-built magneto-optical Kerr effect (MOKE) system in longitudinal arrangement. MOKE measurements show that for a single layer of permalloy (Py), the coercivity of a thin film deposited onto an array of nanospheres increases compared to that of a flat thin film. In addition, the coercivity increases as the nanosphere size decreases for the same deposited layer. It is postulated that magnetic exchange decoupling between neighboring nanocaps suppresses the propagation of magnetic domain walls, and this pinning of the domain walls is thought to be the primary source of the increase in coercivity.

Smart chemical sensors using ZnO semiconducting thin films for freshness detection of foods and beverages

Science.gov (United States)

Nanto, Hidehito; Kobayashi, Toshiki; Dougami, Naganori; Habara, Masaaki; Yamamoto, Hajime; Kusano, Eiji; Kinbara, Akira; Douguchi, Yoshiteru

1998-07-01

The sensitivity of the chemical sensor, based on the resistance change of Al2O3-doped and SnO2-doped ZnO (ZnO:Al and ZnO:SnO2) thin film, is studied for exposure to various gases. It is found that the ZnO:Al and ZnO:Sn thin film chemical sensor has a high sensitivity and excellent selectivity for amine (TMA and DMA) gas and ethanol gas, respectively. The ZnO:Al (5.0 wt%) thin film chemical sensor which exhibit a high sensitivity for exposure to odors from rotten sea foods, such as salmon, sea bream, oyster, squid and sardine, responds to the freshness change of these sea foods. The ZnO:SnO2 (78 wt%) thin film chemical sensor which exhibit a high sensitivity for exposure to aroma from alcohols, such as wine, Japanese sake, and whisky, responds to the freshness change of these alcohols.

Effect of helium gas pressure on dc conduction mechanism and EMI shielding properties of nanocrystalline carbon thin films

Energy Technology Data Exchange (ETDEWEB)

Rawal, Ishpal, E-mail: rawalishpal@gmail.com [Department of Physics, Kirori Mal College, University of Delhi, Delhi 110007 (India); Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Singh, Avanish Pratap; Dhawan, S.K. [Polymeric and Soft Materials Group, Physics Engineering of Carbon, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India)

2015-05-05

This paper reports the effect of helium partial pressures ∼1.2 × 10{sup −5} (base pressure), 1.4 × 10{sup −4}, 8.6 × 10{sup −3} and 0.1 mbar on the variable range hopping conduction in nanocrystalline carbon thin films deposited by filtered cathodic jet carbon arc technique. High resolution transmission electron microscopy studies suggest the random distribution of nanocrystallites (∼3–7 nm) in the amorphous matrix. The DC conduction behavior of the deposited nanocrystalline films has been studied in the light of Mott's variable range hopping (VRH) model and found to obey three dimensional VRH conduction. The randomly distributed nanocrystallites in amorphous matrix may lead to change in the distribution of density of states near Fermi level and hence, the conduction behavior. The enhanced electrical conductivity of the deposited films due to the helium environment makes them suitable for electromagnetic interference shielding applications. The sample deposited at a helium partial pressure of 0.1 mbar has a value of shielding effectiveness ∼7.84 dB at 18 GHz frequency. - Highlights: • Nanocrystalline carbon thin films (NCTF) has been deposited by FCJCA technique. • Effect of helium gas pressure has been studied on the properties of NCTF. • Investigation of EMI shielding properties of NCTF has been carried out.

The Effect of Thickness on the Physical Properties of Fe2O3 Thin Films Prepared by DC Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Baha'a A. Al-Hilli

2017-11-01

Full Text Available The objective of this study is to assess the influence of nano-particle Fe2O3 thin film thickness on some physical properties which were prepared by magnetron DC- sputtering on glass substrate at room temperature. The structure was tested with X-Ray diffraction and it was to be amorphous and to become single crystal with recognized peak in (003 after annealing at temperature 500oC. The physical properties as a function of deposition parameters and then film thickness were studied. The optical properties such as absorbance, energy gap and some optical constants are measured and found that of about (3eV energy gap.

Low resistivity of Ni–Al co-doped ZnO thin films deposited by DC magnetron sputtering at low sputtering power

Energy Technology Data Exchange (ETDEWEB)

Lee, JongWoo [Department of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Hui, K.N. [Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Hui, K.S., E-mail: kshui@hanyang.ac.kr [Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Cho, Y.R., E-mail: yescho@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Chun, Ho-Hwan [Global Core Research Center for Ships and Offshore Plants (GCRC-SOP), Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

2014-02-28

Ni–Al co-doped ZnO (NiAl:ZnO) thin films were deposited on glass substrates by DC magnetron sputtering in Ar using a single ceramic, spark-plasma-sintered target with 2 wt% Al and 5 wt% Ni. The effects of the sputtering power and gas pressure on the NiAl:ZnO films were studied. The structural, electrical, and optical properties of the films were characterized by X-ray diffraction, field emission scanning electron microscopy, Hall effect measurements and UV–vis transmission spectroscopy. As the sputtering power and gas pressure increased, the crystallinity, electrical properties and optical band gap of the films were improved. The NiAl:ZnO film deposited at 40 W at 6.0 mTorr had the strongest (0 0 2) XRD peak and the lowest resistivity of approximately 2.19 × 10{sup −3} Ω cm with an optical transmittance of 90%.

Characteristics of an HTS-SQUID gradiometer with ramp-edge Josephson junctions and its application on robot-based 3D-mobile compact SQUID NDE system

Energy Technology Data Exchange (ETDEWEB)

Hatsukade, Y., E-mail: hatukade@ens.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Hayashi, K.; Shinyama, Y.; Kobayashi, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Adachi, S.; Tanabe, K. [International Superconductivity Technology Center/Superconductivity Research Laboratory, 10-13, Shinonome 1-chome, Koto-ku, Tokyo 135-0062 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

2011-11-15

We investigated behavior of HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in ac and dc magnetic fields. In the both fields, the gradiometers show higher durability against entry of flux vortices than SQUIDs with bicrystal JJs. A robot-based SQUID NDE system utilizing the gradiometer was developed in an unshielded environment. Detectability of the system to detect non-through cracks in double-layer structures was demonstrated. A new excitation coil was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer. In this paper, we investigated detailed behavior of novel HTS-dc-SQUID gradiometers with ramp-edge Josephson junctions (JJs) in both an ac magnetic field and a dc magnetic field. In the both fields, the novel gradiometers shows the superior performance to the conventional YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) HTS-dc-SQUID gradiometer and a bare HTS-dc-SQUID ring with bicrystal JJs concerning durability against entry and hopping of flux vortices, probably due to their differential pickup coils without a grain boundary and multilayer structure of the ramp-edge JJs. A robot-based compact HTS-SQUID NDE system utilizing the novel gradiometer was reviewed, and detectability of the system to detect non-through cracks in a carbon fiber reinforced plastic (CFRP)/Al double-layer structure was demonstrated. A new excitation coil in which the supplied currents flowed in the orthogonal directions was applied to detect cracks that oriented vertical and parallel to the baseline of the gradiometer.

Review of SQUID Sensors for Measuring Magnetocardiography

Energy Technology Data Exchange (ETDEWEB)

Lee, Y. H.; Kim, J. M.; Yu, K. K.; Kim, K.; Kwon, H. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2011-08-15

Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

Biocompatibility and Surface Properties of TiO2 Thin Films Deposited by DC Magnetron Sputtering

Science.gov (United States)

López-Huerta, Francisco; Cervantes, Blanca; González, Octavio; Hernández-Torres, Julián; García-González, Leandro; Vega, Rosario; Herrera-May, Agustín L.; Soto, Enrique

2014-01-01

We present the study of the biocompatibility and surface properties of titanium dioxide (TiO2) thin films deposited by direct current magnetron sputtering. These films are deposited on a quartz substrate at room temperature and annealed with different temperatures (100, 300, 500, 800 and 1100 °C). The biocompatibility of the TiO2 thin films is analyzed using primary cultures of dorsal root ganglion (DRG) of Wistar rats, whose neurons are incubated on the TiO2 thin films and on a control substrate during 18 to 24 h. These neurons are activated by electrical stimuli and its ionic currents and action potential activity recorded. Through X-ray diffraction (XRD), the surface of TiO2 thin films showed a good quality, homogeneity and roughness. The XRD results showed the anatase to rutile phase transition in TiO2 thin films at temperatures between 500 and 1100 °C. This phase had a grain size from 15 to 38 nm, which allowed a suitable structural and crystal phase stability of the TiO2 thin films for low and high temperature. The biocompatibility experiments of these films indicated that they were appropriated for culture of living neurons which displayed normal electrical behavior. PMID:28788667

Structure, adhesive strength and electrochemical performance of nitrogen doped diamond-like carbon thin films deposited via DC magnetron sputtering.

Science.gov (United States)

Khun, N W; Liu, E; Krishna, M D

2010-07-01

Nitrogen doped diamond-like carbon (DLC:N) thin films were deposited on p-Si (100) substrates by DC magnetron sputtering with different nitrogen flow rates at a substrate temperature of about 100 degrees C. The chemical bonding structure of the films was characterized by X-ray photoelectron spectroscopy (XPS) and micro-Raman spectroscopy. The adhesive strength and surface morphology of the films were studied using micro-scratch tester and scanning electron microscope (SEM), respectively. The electrochemical performance of the films was evaluated by potentiodynamic polarization testing and linear sweep voltammetry. The electrolytes used for the electrochemical tests were deaerated and unstirred 0.47 M KCl aqueous solution for potentiodynamic polarization testing and 0.2 M KOH and 0.1 M KCl solutions for voltammetric analysis. It was found that the DLC:N films could well passivate the underlying substrates though the corrosion resistance of the films decreased with increased nitrogen content in the films. The DLC:N films showed wide potential windows in the KOH solution, in which the detection ability of the DLC:N films to trace lead of about 1 x 10(-3) M Pb(2+) was also tested.

DC current distribution mapping system of the solar panels using a HTS-SQUID gradiometer

International Nuclear Information System (INIS)

Miyazaki, Shingo; Kasuya, Syohei; Saari, Mohd Mawardi; Sakai, Kenji; Kiwa, Toshihiko; Tsukada, Keiji; Tsukamoto, Akira; Adachi, Seiji; Tanabe, Keiichi

2014-01-01

Solar panels are expected to play a major role as a source of sustainable energy. In order to evaluate solar panels, non-destructive tests, such as defect inspections and response property evaluations, are necessary. We developed a DC current distribution mapping system of the solar panels using a High Critical Temperature Superconductor Superconducting Quantum Interference Device (HTS-SQUID) gradiometer with ramp edge type Josephson junctions. Two independent components of the magnetic fields perpendicular to the panel surface (∂Bz/∂x, ∂Bz/∂y) were detected. The direct current of the solar panel is visualized by calculating the composition of the two signal components, the phase angle, and mapping the DC current vector. The developed system can evaluate the uniformity of DC current distributions precisely and may be applicable for defect detection of solar panels.

Room temperature growth of nanocrystalline anatase TiO{sub 2} thin films by dc magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Singh, Preetam, E-mail: preetamphy@gmail.co [Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Kaur, Davinder [Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

2010-03-01

We report, the structural and optical properties of nanocrystalline anatase TiO{sub 2} thin films grown on glass substrate by dc magnetron sputtering at room temperature. The influence of sputtering power and pressure over crystallinity and surface morphology of the films were investigated. It was observed that increase in sputtering power activates the TiO{sub 2} film growth from relative lower surface free energy to higher surface free energy. XRD pattern revealed the change in preferred orientation from (1 0 1) to (0 0 4) with increase in sputtering power, which is accounted for different surface energy associated with different planes. Microstructure of the films also changes from cauliflower type to columnar type structures with increase in sputtering power. FESEM images of films grown at low pressure and low sputtering power showed typical cauliflower like structure. The optical measurement revealed the systematic variation of the optical constants with deposition parameters. The films are highly transparent with transmission higher than 90% with sharp ultraviolet cut off. The transmittance of these films was found to be influenced by the surface roughness and film thickness. The optical band gap was found to decrease with increase in the sputtering power and pressure. The refractive index of the films was found to vary in the range of 2.50-2.24 with increase in sputtering pressure or sputtering power, resulting in the possibility of producing TiO{sub 2} films for device applications with different refractive index, by changing the deposition parameters.

Recent progress in thin film processing by magnetron sputtering with plasma diagnostics

International Nuclear Information System (INIS)

Han, Jeon G

2009-01-01

The precise control of the structure and related properties becomes crucial for sophisticated applications of thin films deposited by magnetron sputtering in emerging industries including the flat panel display, digital electronics and nano- and bio-industries. The film structure is closely related to the total energy delivered to the substrate surface for nucleation and growth during all kinds of thin film processes, including magnetron sputtering. Therefore, the energy delivered to the surface for nucleation and growth during magnetron sputtering should be measured and analysed by integrated diagnostics of the plasma parameters which are closely associated with the process parameters and other external process conditions. This paper reviews the background of thin film nucleation and growth, the status of magnetron sputtering technology and the progress of plasma diagnostics for plasma processing. The evolution of the microstructure during magnetron sputtering is then discussed with respect to the change in the process variables in terms of the plasma parameters along with empirical data of the integrated plasma diagnostics for various magnetron sputtering conditions with conventional dc, pulsed dc and high power pulsed dc sputtering modes. Among the major energy terms to be discussed are the temperature change in the top surface region and the energies of ions and neutral species. (topical review)

Anomalous DC dark conductivity behaviour in a-Se films

International Nuclear Information System (INIS)

Qamhieh, N; Willekens, J; Brinza, M; Adriaenssens, G J

2003-01-01

Thin films of amorphous selenium have been prepared by thermal evaporation. DC conductivity measurements were carried out on these films in the temperature range between 208 and 322 deg. K. Above room temperature, the dark conductivity is thermally activated with activation energy E σ 1.05 ± 0.08 eV. For temperatures below 285 deg. K, an increase in the dark current is observed, which is interpreted in terms of a shift of the Fermi level that makes more states available for a hopping process. (letter to the editor)

Modified lead titanate thin films for pyroelectric infrared detectors on gold electrodes

Science.gov (United States)

Ahmed, Moinuddin; Butler, Donald P.

2015-07-01

Pyroelectric infrared detectors provide the advantage of both a wide spectral response and dynamic range, which also has enabled systems to be developed with reduced size, weight and power consumption. This paper demonstrates the deposition of lead zirconium titanate (PZT) and lead calcium titanate (PCT) thin films for uncooled pyroelectric detectors with the utilization of gold electrodes. The modified lead titanate thin films were deposited by pulsed laser deposition on gold electrodes. The PZT and PCT thins films deposited and annealed at temperatures of 650 °C and 550 °C respectively demonstrated the best pyroelectric performance in this work. The thin films displayed a pyroelectric effect that increased with temperature. Poling of the thin films was carried out for a fixed time periods and fixed dc bias voltages at elevated temperature in order to increase the pyroelectric coefficient by establishing a spontaneous polarization of the thin films. Poling caused the pyroelectric current to increase one order of magnitude.

X-ray magnetic spectroscopy of MBE-grown Mn-doped Bi2Se3 thin films

Directory of Open Access Journals (Sweden)

L. J. Collins-McIntyre

2014-12-01

Full Text Available We report the growth of Mn-doped Bi2Se3 thin films by molecular beam epitaxy (MBE, investigated by x-ray diffraction (XRD, atomic force microscopy (AFM, SQUID magnetometry and x-ray magnetic circular dichroism (XMCD. Epitaxial films were deposited on c-plane sapphire substrates by co-evaporation. The films exhibit a spiral growth mechanism typical of this material class, as revealed by AFM. The XRD measurements demonstrate a good crystalline structure which is retained upon doping up to ∼7.5 atomic-% Mn, determined by Rutherford backscattering spectrometry (RBS, and show no evidence of the formation of parasitic phases. However an increasing interstitial incorporation of Mn is observed with increasing doping concentration. A magnetic moment of 5.1 μB/Mn is obtained from bulk-sensitive SQUID measurements, and a much lower moment of 1.6 μB/Mn from surface-sensitive XMCD. At ∼2.5 K, XMCD at the Mn L2,3 edge, reveals short-range magnetic order in the films and indicates ferromagnetic order below 1.5 K.

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

International Nuclear Information System (INIS)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju; Son, Myoungwoo; Ham, Moon-Ho; Lee, Woong; Myoung, Jae-Min

2012-01-01

Highlights: ► Surface-textured AZO films were achieved by combining PDMS method with wet etching. ► The AZO film deposited at 230 °C by PDMS exhibited the best performance. ► It is due to the higher plasma density supplied from PDMS system. ► Wet etching of the films produces a crater-like rough surface morphology. - Abstract: A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 °C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 × 10 −4 Ω cm with the carrier concentration of 1.65 × 10 21 cm −3 and Hall mobility of 11.3 cm 2 /V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

The Optimum Fabrication Condition of p-Type Antimony Tin Oxide Thin Films Prepared by DC Magnetron Sputtering

Directory of Open Access Journals (Sweden)

Huu Phuc Dang

2016-01-01

Full Text Available Transparent Sb-doped tin oxide (ATO thin films were fabricated on quartz glass substrates via a mixed (SnO2 + Sb2O3 ceramic target using direct current (DC magnetron sputtering in ambient Ar gas at a working pressure of 2 × 10−3 torr. X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, Hall-effect, and UV-vis spectra measurements were performed to characterize the deposited films. The substrate temperature of the films was investigated in two ways: (1 films were annealed in Ar ambient gas after being deposited at room temperature or (2 they were deposited directly at different temperatures. The first process for fabricating the ATO films was found to be easier than the second process. The deposited films showed p-type electrical properties, a polycrystalline tetragonal rutile structure, and their average transmittance was greater than 80% in the visible light range at the optimum annealing temperature of 500°C. The best electrical properties of the film were obtained on a 10 wt% Sb2O3-doped SnO2 target with a resistivity, hole concentration, and Hall mobility of 0.55 Ω·cm, 1.2 × 1019 cm−3, and 0.54 cm2V−1s−1, respectively.

SBA-15 mesoporous silica free-standing thin films containing copper ions bounded via propyl phosphonate units - preparation and characterization

Energy Technology Data Exchange (ETDEWEB)

Laskowski, Lukasz, E-mail: lukasz.laskowski@kik.pcz.pl [Czestochowa University of Technology, Institute of Computational Intelligence, Unit of Microelectronics and Nanotechnology, Al. Armii Krajowej 36, 42–201 Czestochowa (Poland); Laskowska, Magdalena, E-mail: magdalena.laskowska@onet.pl [H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakow, ul. Radzikowskiego 152 (Poland); Jelonkiewicz, Jerzy, E-mail: jerzy.jelonkiewicz@kik.pcz.pl [Czestochowa University of Technology, Institute of Computational Intelligence, Unit of Microelectronics and Nanotechnology, Al. Armii Krajowej 36, 42–201 Czestochowa (Poland); Dulski, Mateusz, E-mail: mateusz.dulski@us.edu.pl [University of Silesia, Faculty of Computer Science and Materials Science, Institute of Materials Science, Silesian Center for Education and Interdisciplinary Research, ul. 75 Pułku Piechoty 1A, 41–500 Chorzów (Poland); Wojtyniak, Marcin, E-mail: marcin.wojtyniak@us.edu.pl [University of Silesia, Institute of Physics, Silesian Center for Education and Interdisciplinary Research, ul. 75 Pułku Piechoty 1A, 41–500 Chorzów (Poland); Fitta, Magdalena, E-mail: magdalena.fitta@ifj.edu.pl [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, 31–342 Krakow, ul. Radzikowskiego 152 (Poland); Balanda, Maria, E-mail: Maria.Balanda@ifj.edu.pl [H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, 31–342 Krakow, ul. Radzikowskiego 152 (Poland)

2016-09-15

The SBA-15 silica thin films containing copper ions anchored inside channels via propyl phosphonate groups are investigated. Such materials were prepared in the form of thin films, with hexagonally arranged pores, laying rectilinear to the substrate surface. However, in the case of our thin films, their free standing form allowed for additional research possibilities, that are not obtainable for typical thin films on a substrate. The structural properties of the samples were investigated by X-ray reflectometry, atomic force microscopy (AFM) and transmission electron microscopy (TEM). The molecular structure was examined by Raman spectroscopy supported by numerical simulations. Magnetic measurements (SQUID magnetometry and EPR spectroscopy) showed weak antiferromagnetic interactions between active units inside silica channels. Consequently, the pores arrangement was determined and the process of copper ions anchoring by propyl phosphonate groups was verified in unambiguous way. Moreover, the type of interactions between magnetic atoms was determined. - Highlights: • Functionalized free-standing SBA-15 thin films were synthesized for a first time. • Thin films synthesis procedure was described in details. • Structural properties of the films were thoroughly investigated and presented. • Magnetic properties of the novel material was investigated and presented.

Zn{sub x}Zr{sub y}O{sub z} thin films grown by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Sanchez, O. [Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid (Spain); Hernandez-Velez, M. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid (Spain)

2017-10-15

The structural and optical properties of thin films deposited by DC reactive magnetron co-sputtering using Zn and Zr targets in argon and oxygen gas mixtures at room temperature are reported. The power applied to the Zr cathode was kept constant, while that applied to the Zn cathode was varied between 0 and 150 W to produce very different Zn{sub x}Zr{sub y}O{sub z} ternary compounds with Zn/Zr atomic ratios in the range of 0.1-10. The composition, crystalline structure, and optical properties of the samples were determined by EDX, XRD, FTIR, and UV-visible spectroscopies. The grown films are polycrystalline, and the preferred crystallographic orientation depends on the Zn atomic concentration in the film. The optical transmission in the UV-visible range is approximately 80% in all cases, and as the Zn atomic content increases, the absorption edge shifts to longer wavelengths. The optical band gap, E{sub g}, shifted from 5.5 to 3.5 eV when the Zn/Zr atomic ratio was increased. The results indicate the potential use of these materials in optoelectronic applications. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Corrosion of thin, magnetron sputtered Nb_2O_5 films

International Nuclear Information System (INIS)

Pillis, Marina Fuser; Geribola, Guilherme Altomari; Scheidt, Guilherme; Gonçalves de Araújo, Edval; Lopes de Oliveira, Mara Cristina; Antunes, Renato Altobelli

2016-01-01

Highlights: • Niobium oxide based films were obtained by DC magnetron sputtering. • Different deposition times were tested. • The best corrosion resistance was obtained for the Nb_2O_5 film produced at 15′. • Film porosity determines the corrosion resistance. - Abstract: Niobium oxide based thin films were deposited on AISI 316 stainless steel substrates using reactive DC magnetron sputtering. Structure, composition and corrosion resistance of the niobium oxide films were studied. The corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The concentration of niobium and oxygen in the films was obtained by Rutherford backscattering spectroscopy (RBS). The film structure was analyzed by X-ray diffractometry. The corrosion resistance of the substrate was improved by the Nb_2O_5 layers. The best protective performance was achieved for the deposition time of 15 min.

Studies of internal stress in diamond films prepared by DC plasma chemical vapour deposition

International Nuclear Information System (INIS)

Wang Wanlu; Gao Jinying; Liao Kejun; Liu Anmin

1992-01-01

The internal stress in diamond thin films deposited by DC plasma CVD was studied as a function of methane concentration and deposited temperature. Experimental results have shown that total stress in diamond thin films is sensitive to the deposition conditions. The results also indicate that the compressive stress can be explained in terms of amorphous state carbon and hydrogen, and tensile stress is ascribed to the grain boundary relaxation model due to high internal surface area and microstructure with voids

Tc depression and superconductor-insulator transition in molybdenum nitride thin films

Science.gov (United States)

Ichikawa, F.; Makise, K.; Tsuneoka, T.; Maeda, S.; Shinozaki, B.

2018-03-01

We have studied that the Tc depression and the superconductor-insulator transition (SIT) in molybdenum nitride (MoN) thin films. Thin films were fabricated by reactive DC magnetron sputtering method onto (100) MgO substrates in the mixture of Ar and N2 gases. Several dozen MoN thin films were prepared in the range of 3 nm < thickness d < 60 nm. The resistance was measured by a DC four-probe technique. It is found that Tc decreases from 6.6 K for thick films with increase of the normal state sheet resistance {R}{{sq}}{{N}} and experimental data were fitted to the Finkel’stein formula using the bulk superconducting transition temperature Tc 0 = 6.45 K and the elastic scattering time of electron τ = 1.6 × 10‑16 s. From this analysis the critical sheet resistance Rc is found about 2 kΩ, which is smaller than the quantum sheet resistance R Q. This value of Rc is almost the same as those for 2D NbN films. The value of τ for MoN films is also the similar value for NbN films 1.0 × 10‑16 s, while Tc 0 is different from that for NbN films 14.85 K. It is indicated that the mechanism of SIT for MoN films is similar to that of NbN films, while the mean free path ℓ for MoN films is larger than that for NbN films.

Effect of argon addition into oxygen atmosphere on YBCO thin films deposition

International Nuclear Information System (INIS)

Mozhaev, P. B.; Borisenko, I. V.; Ovsyannikov, G. A.; Kuehle, A.; Bindslev-Hansen, J.; Johannes, L.; Skov, J. L.

2002-01-01

Multicomponent nature of the YBa 2 Cu 3 O x (YBCO) high-temperature superconductor makes difficult fabrication of smooth thin films: every local deviation from stoichiometry can result in seeding of a non-superconducting oxide particle. High density of such particles on typical YBCO thin film surface, however, presumes overall non-stoichiometry of the film. Such an effect can result from (i) non-uniform material transport from target to substrate, and (ii) re-evaporation or re-sputtering from the growing film surface. The first reason is more usual for laser ablation deposition technique, the second is typical for long sputtering deposition processes. Substitution of oxygen with argon in the deposition atmosphere improves surface quality of YBCO thin films deposited both by laser ablation and DC-sputtering at high pressure techniques. In the first case, the ablated species are scattered different ways in the oxygen atmosphere. Addition of argon decreases the inelastic scattering of barium; the proper part of Ar in the deposition atmosphere makes scattering and, hence, transport of all atoms uniform. The YBCO films deposited by DC-sputtering at high pressure technique are Ba-deficient also, but the reason is re-sputtering of Ba from the growing film as a result of negative oxygen ions bombardment. Such bombardment can lead also to chemical interaction of the deposited material with the substrate, as in the case of deposition of YBCO thin film on the CeO 2 buffer layer on sapphire. Substitution of oxygen with argon not only suppresses ion bombardment of the film, but also increases discharge stability due to presence of positive Ar + ions. The limiting factor of argon substitution is sufficient oxygenation of the growing oxide film. When oxygen partial pressure is too small, the superconducting quality of the YBCO thin film decreases and such a decrease cannot be overcome by prolonged oxygenation after deposition. (Authors)

Domain Engineered Magnetoelectric Thin Films for High Sensitivity Resonant Magnetic Field Sensors

Science.gov (United States)

2011-12-01

band gap of highly textured PZT thin films. The deposition process variables were - argon and oxygen flows, chamber pressure, RF power (DC Bias...needed another parameter to equate with the number of unknowns in the resultant model equations. From Figure 24, electronic polarizability affects the... Polarizability and Optical dielectric response of a thin.film , ., ,__~--~---\\- 000 01’ "󈧶 Ots Tncnt.re"’°l Effective Polarizability = Reddy

SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

Science.gov (United States)

Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

2016-05-01

The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

A fatigue test method for Pb(Zr,Ti)O3 thin films by using MEMS-based self-sensitive piezoelectric microcantilevers

Science.gov (United States)

Kobayashi, T.; Maeda, R.; Itoh, T.

2008-11-01

In the present study, we propose a new method for the fatigue test of lead zirconate titanate (PZT) thin films for MEMS devices by using self-sensitive piezoelectric microcantilevers developed in our previous study. We have deposited PZT thin films on SOI wafers and fabricated the microcantilevers through the MEMS microfabrication process. In the self-sensitive piezoelectric microcantilevers, the PZT thin films are separated in order to act as an actuator and a sensor. The fatigue characteristic of the PZT thin films can be evaluated by measuring the output voltage of the sensor as a function of time. When a sine wave of 20 Vpp and a dc bias of 10 V were applied to the PZT thin films for an actuator, the output voltage of the sensor fell down after 107 fatigue cycles. We have also investigated the influence of amplitude of the actuation sine wave and dc bias on the fatigue of the PZT thin films by using the proposed fatigue test method.

A fatigue test method for Pb(Zr,Ti)O3 thin films by using MEMS-based self-sensitive piezoelectric microcantilevers

International Nuclear Information System (INIS)

Kobayashi, T; Maeda, R; Itoh, T

2008-01-01

In the present study, we propose a new method for the fatigue test of lead zirconate titanate (PZT) thin films for MEMS devices by using self-sensitive piezoelectric microcantilevers developed in our previous study. We have deposited PZT thin films on SOI wafers and fabricated the microcantilevers through the MEMS microfabrication process. In the self-sensitive piezoelectric microcantilevers, the PZT thin films are separated in order to act as an actuator and a sensor. The fatigue characteristic of the PZT thin films can be evaluated by measuring the output voltage of the sensor as a function of time. When a sine wave of 20 V pp and a dc bias of 10 V were applied to the PZT thin films for an actuator, the output voltage of the sensor fell down after 10 7 fatigue cycles. We have also investigated the influence of amplitude of the actuation sine wave and dc bias on the fatigue of the PZT thin films by using the proposed fatigue test method

Synthesis and characterization of MoB2−x thin films grown by nonreactive DC magnetron sputtering

International Nuclear Information System (INIS)

Malinovskis, Paulius; Lewin, Erik; Jansson, Ulf; Palisaitis, Justinas; Persson, Per O. Å.

2016-01-01

DC magnetron sputtering was used to deposit molybdenum boride thin films for potential low-friction applications. The films exhibit a nanocomposite structure with ∼10 nm large MoB 2−x (x > 0.4) grains surrounded by a boron-rich tissue phase. The preferred formation of the metastable and substoichiometric hP3-MoB 2 structure (AlB 2 -type) is explained with kinetic constraints to form the thermodynamically stable hR18-MoB 2 phase with a very complex crystal structure. Nanoindentation revealed a relatively high hardness of (29 ± 2) GPa, which is higher than bulk samples. The high hardness can be explained by a hardening effect associated with the nanocomposite microstructure where the surrounding tissue phase restricts dislocation movement. A tribological study confirmed a significant formation of a tribofilm consisting of molybdenum oxide and boron oxide, however, without any lubricating effects at room temperature.

Effect of deposition temperature on the properties of Al-doped ZnO films prepared by pulsed DC magnetron sputtering for transparent electrodes in thin-film solar cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Doo-Soo; Park, Ji-Hyeon; Shin, Beom-Ki; Moon, Kyeong-Ju [Information and Electronic Materials Research Laboratory, Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Son, Myoungwoo [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Ham, Moon-Ho [Department of Nanobio Materials and Electronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Lee, Woong [School of Nano and Advanced Materials Engineering, Changwon National University, 9 Sarim-Dong, Changwon, Gyeongnam 641-773 (Korea, Republic of); Myoung, Jae-Min, E-mail: jmmyoung@yonsei.ac.kr [Information and Electronic Materials Research Laboratory, Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2012-10-15

Highlights: Black-Right-Pointing-Pointer Surface-textured AZO films were achieved by combining PDMS method with wet etching. Black-Right-Pointing-Pointer The AZO film deposited at 230 Degree-Sign C by PDMS exhibited the best performance. Black-Right-Pointing-Pointer It is due to the higher plasma density supplied from PDMS system. Black-Right-Pointing-Pointer Wet etching of the films produces a crater-like rough surface morphology. - Abstract: A simple but scalable approach to the production of surface-textured Al-doped ZnO(AZO) films for low-cost transparent electrode applications in thin-film solar cells is introduced in this study by combining pulsed dc magnetron sputtering (PDMS) with wet etching in sequence. First, structural, electrical, and optical properties of the AZO films prepared by a PDMS were investigated as functions of deposition temperature to obtain transparent electrode films that can be used as indium-free alternative to ITO electrodes. Increase in the deposition temperature to 230 Degree-Sign C accompanied the improvement in crystalline quality and doping efficiency, which enabled the lowest electrical resistivity of 4.16 Multiplication-Sign 10{sup -4} {Omega} cm with the carrier concentration of 1.65 Multiplication-Sign 10{sup 21} cm{sup -3} and Hall mobility of 11.3 cm{sup 2}/V s. The wet etching of the films in a diluted HCl solution resulted in surface roughening via the formation of crater-like structures without significant degradation in the electrical properties, which is responsible for the enhanced light scattering capability required for anti-reflective electrodes in thin film solar cells.

Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

Energy Technology Data Exchange (ETDEWEB)

Sharma, Shilpam; Amaladass, E.P. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Sharma, Neha [Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Harimohan, V. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Mani, Awadhesh, E-mail: mani@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2017-06-01

Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples. - Highlights: • Thin films of molybdenum using DC sputtering have been deposited on glass. • Argon background pressure during sputtering was used to tune the crystallite sizes of films. • Correlation in deposition pressure, disorder and particle sizes has been observed. • Disorder tuned superconductor to insulator transition along with an intermediate metallic phase has been observed. • Enhancement of superconducting transition temperature and a dome shaped T{sub C} vs. deposition pressure phase diagram has been observed.

Investigation of the optical property and structure of WO3 thin films with different sputtering depositions

Science.gov (United States)

Chen, Hsi-Chao; Jan, Der-Jun; Chen, Chien-Han; Huang, Kuo-Ting; Lo, Yen-Ming; Chen, Sheng-Hui

2011-09-01

The purpose of this research was to compare the optical properties and structure of tungsten oxide (WO3) thin films that was deposited by different sputtering depositions. WO3 thin films deposited by two different depositions of direct current (DC) magnetron sputtering and pulsed DC sputtering. A 99.95% WO3 target was used as the starting material for these depositions. These WO3 thin films were deposited on the ITO glass, PET and silicon substrate by different ratios of oxygen and argon. A shadow moiré interferometer would be introduced to measure the residual stress for PET substrate. RF magnetron sputtering had the large residual stress than the other's depositions. A Raman spectrum could exhibit the phase of oxidation of WO3 thin film by different depositions. At the ratio of oxygen and argon was about 1:1, and the WO3 thin films had the best oxidation. However, it was important at the change of the transmittance (ΔT = Tbleached - Tcolored) between the coloring and bleaching for the smart window. Therefore, we also found the WO3 thin films had the large variation of transmittance between the coloring and bleaching at the gas ratios of oxygen and argon of 1:1.

Magnetic and structural study of Cu-doped TiO2 thin films

International Nuclear Information System (INIS)

Torres, C.E. Rodriguez; Golmar, F.; Cabrera, A.F.; Errico, L.; Navarro, A.M. Mudarra; Renteria, M.; Sanchez, F.H.; Duhalde, S.

2007-01-01

Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO 2 thin films were grown by pulsed laser deposition technique on LaAlO 3 substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO 2 . The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO 2

Morphology, structure, and electrical properties of YBa{sub 2}Cu{sub 3}O{sub x} thin films on tilted NdGaO{sub 3} substrates, deposited by DC-sputtering

Energy Technology Data Exchange (ETDEWEB)

Mozhaev, Peter B. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation)]. E-mail: pbmozh@nm.ru; Kotelyanskii, Iosif M. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Luzanov, Valery A. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Mozhaeva, Julia E. [Institute of Radio Engineering and Electronics RAS, Moscow 125009 (Russian Federation); Donchev, Todor [Institute of Electronics BAS, Sofia (Bulgaria); Mateev, Emil [Institute of Electronics BAS, Sofia (Bulgaria); Nurgaliev, Timur [Institute of Electronics BAS, Sofia (Bulgaria); Bdikin, Igor K. [Institute of Solid State Physics RAS, Chernogolovka, Moscow 142432 (Russian Federation); Department of Ceramic and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193 (Portugal); Narymbetov, Bakhyt Zh. [Complex Institute of Natural Sciences UzAS, Nukus (Uzbekistan)

2005-02-15

Thin YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) films were deposited using DC-sputtering technique on NdGaO{sub 3} substrates, tilted from (1 1 0) orientation by 0-26 deg . The structure and surface quality of the substrates were carefully characterized to obtain reliable results of thin films deposition. Structural, morphological and electrical properties of the YBCO thin films show three different ranges of inclination angle: vicinal, intermediate and high. In the vicinal range the properties of the film are generally the same as of the standard films deposited on (1 1 0) NdGaO{sub 3} substrate. An increase of the inclination angle to the intermediate range results in a significant improvement of morphology and structural quality of the film. Best electrical parameters are measured for the films of the intermediate range also. Probable reason for such behavior is simultaneous and regular seeding of the film in the joints of facets on the substrate surface. Further increase of inclination angle leads to step bunching and oxygen out-diffusion, destroying both structural and electrical perfection of the tilted-axes YBCO film.

The optical properties of plasma polymerized polyaniline thin films

Energy Technology Data Exchange (ETDEWEB)

Goktas, Hilal, E-mail: hilal_goktas@yahoo.com [Canakkale Onsekiz Mart University, Physics Department, 17020 Canakkale (Turkey); Demircioglu, Zahide; Sel, Kivanc [Canakkale Onsekiz Mart University, Physics Department, 17020 Canakkale (Turkey); Gunes, Taylan [Yalova University, Energy Systems Engineering Department, 77100 Yalova (Turkey); Kaya, Ismet [Canakkale Onsekiz Mart University, Chemistry Department, 17020 Canakkale (Turkey)

2013-12-02

We report herein the characterizations of polyaniline thin films synthesized using double discharge plasma system. Quartz glass substrates were coated at a pressure of 80 Pa, 19.0 kV pulsed and 1.5 kV dc potential. The substrates were located at different regions in the reactor to evaluate the influence of the position on the morphological and molecular structure of the obtained thin films. The molecular structure of the thin films was investigated by Fourier transform infrared (FTIR) and UV–visible photospectrometers (UV–vis), and the morphological studies were carried out by scanning electron microscope. The FTIR and UV–vis data revealed that the molecular structures of the synthesized thin films were in the form of leuocoemeraldine and exhibited similar structures with the films produced via chemical or electrochemical methods. The optical energy band gap values of the as-grown samples ranged from 2.5 to 3.1 eV, which indicated that these materials have potential applications in semiconductor devices. The refractive index in the transparent region (from 650 to 1000 nm) steadily decreased from 1.9 to 1.4 and the extinction coefficient was found to be on order of 10{sup −4}. The synthesized thin films showed various degrees of granular morphologies depending on the location of the substrate in the reactor. - Highlights: • Polyaniline thin films were synthesized for the first time via double discharge plasma system. • The films have similar structure to that of the chemically synthesized films. • The morphology of the films could be tuned by this technique. • These materials would have potential applications at semiconductor devices.

Piezoelectric response of a PZT thin film to magnetic fields from permanent magnet and coil combination

Science.gov (United States)

Guiffard, B.; Seveno, R.

2015-01-01

In this study, we report the magnetically induced electric field E 3 in Pb(Zr0.57Ti0.43)O3 (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude B ac at 45 kHz) and static magnetic induction ( B dc) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to B dc——is achieved for the thin film with largest effective electrode. This magnetoelectric (ME) effect is interpreted in terms of coupling between eddy current-induced Lorentz forces (stress) in the electrodes of PZT and piezoelectricity. Such coupling was evidenced by convenient modelling of experimental variations of electric field magnitude with both B ac and B dc induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E 3 versus B dc could also be modelled. At last, the results show that similar to multilayered piezoelectric-magnetostrictive composite film, a PZT thin film made with a simple manufacturing process can behave as a static or dynamic magnetic field sensor. In this latter case, a large ME voltage coefficient of under B dc = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems.

Nanocrystalline Pd:NiFe{sub 2}O{sub 4} thin films: A selective ethanol gas sensor

Energy Technology Data Exchange (ETDEWEB)

Rao, Pratibha; Godbole, R.V.; Bhagwat, Sunita, E-mail: smb.agc@gmail.com

2016-10-15

In this work, Pd:NiFe{sub 2}O{sub 4} thin films were investigated for the detection of reducing gases. These films were fabricated using spray pyrolysis technique and characterized using X-ray diffraction (XRD) to confirm the crystal structure. The surface morphology was studied using scanning electron microscopy (SEM). Magnetization measurements were carried out using SQUID VSM, which shows ferrimagnetic behavior of the samples. These thin film sensors were tested against methanol, ethanol, hydrogen sulfide and liquid petroleum gas, where they were found to be more selective to ethanol. The fabricated thin film sensors exhibited linear response signal for all the gases with concentrations up to 5 w/o Pd. Reduction in optimum operating temperature and enhancement in response was also observed. Pd:NiFe{sub 2}O{sub 4} thin films exhibited faster response and recovery characteristic. These sensors have potential for industrial applications because of their long-term stability, low power requirement and low production cost. - Highlights: • Ethanol gas sensors based on Pd:NiFe{sub 2}O{sub 4} nanoparticle thin film were fabricated. • Pd incorporation in NiFe{sub 2}O{sub 4} matrix inhibits grain growth. • The sensors were more selective to ethanol gas. • Sensors exhibited fast response and recovery when doped with palladium. • Pd:NiFe{sub 2}O{sub 4} thin film sensor displays excellent long–term stability.

Magnetic hysteresis measurements of thin films under isotropic stress.

Science.gov (United States)

Holland, Patrick; Dubey, Archana; Geerts, Wilhelmus

2000-10-01

Nowadays, ferromagnetic thin films are widely applied in devices for information technology (credit cards, video recorder tapes, floppies, hard disks) and sensors (air bags, anti-breaking systems, navigation systems). Thus, with the increase in the use of magnetic media continued investigation of magnetic properties of materials is necessary to help in determining the useful properties of materials for new or improved applications. We are currently interested in studying the effect of applied external stress on Kerr hysteresis curves of thin magnetic films. The Ni and NiFe films were grown using DC magnetron sputtering with Ar as the sputter gas (pAr=4 mTorr; Tsub=55-190 C). Seed and cap layers of Ti were used on all films for adhesion and oxidation protection, respectively. A brass membrane pressure cell was designed to apply in-plane isotropic stress to thin films. In this pressure cell, gas pressure is used to deform a flexible substrate onto which a thin magnetic film has been sputtered. The curvature of the samples could be controlled by changing the gas pressure to the cell. Magneto-Optical in-plane hysteresis curves at different values of strain were measured. The results obtained show that the stress sensitivity is dependent on the film thickness. For the 500nm NiFe films, the coercivity strongly decreased as a function of the applied stress.

YBCO SQUIDs with unconventional current phase relation

International Nuclear Information System (INIS)

Bauch, T.; Johansson, J.; Cedergren, K.; Lindstroem, T.; Lombardi, F.

2007-01-01

We have studied the dynamics of YBa 2 Cu 3 O 7-δ (YBCO) dc sperconducting quantum interference devices (SQUIDs) characterized by an unconventional Josephson current phase relation (CPR). We have focused on SQUID configurations with Josephson junctions where the lobe of the order parameter in one electrode is facing a node in the other electrode. This order parameter arrangement should enhance the appearance of a sin(2φ) term in the CPR. The response of the critical current of the dc SQUID, under the effect of an external magnetic field, has been measured in temperature, down to 20 mK. Our experimental data have been compared with numerical simulations of the SQUIDs dynamics by considering a CPR of a single junction of the form I(φ) = I I sin(φ) - I II sin(2φ) where I I and I II are, respectively, the first and second harmonic component. In our devices the values of the sin(2φ) term are such that the fundamental state of the SQUID is naturally double degenerate. This is of great relevance for applications of d-wave SQUIDs in quantum information processing

Texture of the nano-crystalline AlN thin films and the growth conditions in DC magnetron sputtering

Directory of Open Access Journals (Sweden)

Shakil Khan

2015-08-01

Full Text Available DC reactive magnetron sputtering technique has been used for the preparation of AlN thin films. The deposition temperature and the flow ratio of N2/Ar were varied and subsequent dependency of the films crystallites orientation/texture has been addressed. In general, deposited films were found hexagonal polycrystalline with a (002 preferred orientation. The X-ray diffraction (XRD data revealed that the film crystallinity improves, with the increase of substrate temperature from 300 °C to 500 °C. The dropped in full width half maximum (FWHM of the XRD rocking curve value further confirmed it. However, increasing substrate temperature above 500 °C or reducing the nitrogen condition (from 60 to 30% in the environment induced the growth of crystallites with (102 and (103 orientations. The rise of rocking curve FWHM for the corresponding conditions depicted that the films texture quality deteriorated. A further confirmation of the variation in film texture/orentation with the growth conditions has been obtained from the variation in FWHM values of a dominant E1 (TO mode in the Fourier transform infrared (FTIR spectra and the E2 (high mode in Raman spectra. We have correlated the columnar structure in AFM surface analyses with the (002 or c-axis orientation as well. Spectroscopic ellipsometry of the samples have shown a higher refractive index at 500 °C growth temperature.

DC-sputtered MoO{sub x} thin-films as hole transport layer in organic photovoltaic

Energy Technology Data Exchange (ETDEWEB)

Cauduro, Andre L.F.; Ahmadpour, Mehrad; Rubahn, Horst-Guenter; Madsen, Morten, E-mail: cauduro@mci.sdu.dk [NanoSYD, University of Southern Denmark (Denmark); Reis, Roberto dos; Chen, Gong; Schmid, Andreas [National Center for Electron Microscopy, The Molecular Foundry, LBNL, Berkeley, CA (United States); Methivier, Christophe [Sorbonne Universites, UPMC Univ Paris 06, CNRS UMR, Laboratoire de Reactivite de Surface (LRS) (France); Witkowski, Nadine [Sorbonne Universites, UPMC Univ Paris 06, UMR CNRS, Institut des Nanosciences de Paris (INSP) (France); Fichtner, Paulo F.P. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre (Brazil)

2016-07-01

Full text: Molybdenum-oxide (MoO{sub x}) thin-films have attracted a lot of attention in the past years due to their unique ability to act as interfacial layers in novel electronics and energy applications. In the work presented here, large tuning possibilities in the electronic and optoelectronic properties of MoO{sub x} thin-films deposited by reactive sputtering using different oxygen partial pressures and annealing conditions are demonstrated along with the implementation of the films in organic photovoltaic. MoO{sub x} thin-films deposited under low oxygen partial pressure present a high conductivity of around 3.22 S.cm{sup -1}, however, as the oxygen partial pressure increases, the conductivity of the resulting films drops by up to around 10 orders of magnitude as the [O]/[Mo] ratio changes from 2.57 to beyond 3.00. Optical absorption measurements also show drastic changes mostly within the 0.60 eV - 2.50 eV spectral region for the same increase in oxygen concentration in [1]. UPS and XPS studies are conducted for accessing information about the work function and surface composition of the thin-films. The XPS spectra registered on the Mo 3d core level reveal how the oxidation state of Mo is affected by the partial pressure of oxygen during film growth. The work function of the films increase with annealing temperature and oxygen content, and span a tuning range of about 2 eV. To extract the spatially resolved work function values from the sputtered films, we use in addition Low Energy Electron Microscopy (LEEM). Finally, the application of the MoO{sub x} thin-films in organic optoelectronic devices is investigated by employing them as hole transport layers in small molecule photovoltaic, here based on DBP and C70. The work thus demonstrates a viable method for tuning the electronic and optoelectronic properties of MoO{sub x} thin-films, which can be applied in combination with a wide range of materials in e.g. organic photovoltaic. [1] A.L. Fernandes Cauduro

Piezoelectric response of a PZT thin film to magnetic fields from permanent magnet and coil combination

Energy Technology Data Exchange (ETDEWEB)

Guiffard, B.; Seveno, R. [Universite de Nantes, Lunam Universite, IETR UMR CNRS 6164, Nantes (France)

2014-07-10

In this study, we report the magnetically induced electric field E{sub 3} in Pb(Zr{sub 0.57}Ti{sub 0.43})O{sub 3} (PZT) thin films, when they are subjected to both dynamic magnetic induction (magnitude B{sub ac} at 45 kHz) and static magnetic induction (B{sub dc}) generated by a coil and a single permanent magnet, respectively. It is found that highest sensitivity to B{sub dc} - Δ vertical stroke E{sub 3} vertical stroke ΔB{sub dc} - is achieved for the thin film with largest effective electrode. This magnetoelectric (ME) effect is interpreted in terms of coupling between eddy current-induced Lorentz forces (stress) in the electrodes of PZT and piezoelectricity. Such coupling was evidenced by convenient modelling of experimental variations of electric field magnitude with both B{sub ac} and B{sub dc} induction magnitudes, providing imperfect open circuit condition was considered. Phase angle of E{sub 3} versus B{sub dc} could also be modelled. At last, the results show that similar to multilayered piezoelectric-magnetostrictive composite film, a PZT thin film made with a simple manufacturing process can behave as a static or dynamic magnetic field sensor. In this latter case, a large ME voltage coefficient of α = vertical stroke E{sub 3} vertical stroke /B{sub ac} = 3.55 V/cm Oe under B{sub dc} = 0.3 T was found. All these results may provide promising low-cost magnetic energy harvesting applications with microsized systems. (orig.)

Magnetic moment oscillation in ammonium perchlorate in a DC SQUID-based magnetic resonance experiment

International Nuclear Information System (INIS)

Montero, V.; Cernicchiaro, G.

2008-01-01

In this work we describe experimental results in which a DC SQUID (superconducting quantum interference device) is used as free induction decay detector. Measurements of a solid ammonium perchlorate (NH 4 ClO 4 ) sample were performed, in zero field, at 4.2 K. Unexpected magnetic moment oscillations were detected at 1.5 kHz. The computation of the magnetic fields suggests that the proton nuclear magnetic resonance may explain the measured resonance, considering reorientation of the ammonium group by quantum tunneling of protons and a magnetic proton dipole-dipole intermolecular interaction model

Effect of Target Density on Microstructural, Electrical, and Optical Properties of Indium Tin Oxide Thin Films

Science.gov (United States)

Zhu, Guisheng; Zhi, Li; Yang, Huijuan; Xu, Huarui; Yu, Aibing

2012-09-01

In this paper, indium tin oxide (ITO) targets with different densities were used to deposit ITO thin films. The thin films were deposited from these targets at room temperature and annealed at 750°C. Microstructural, electrical, and optical properties of the as-prepared films were studied. It was found that the target density had no effect on the properties or deposition rate of radiofrequency (RF)-sputtered ITO thin films, different from the findings for direct current (DC)-sputtered films. Therefore, when using RF sputtering, the target does not require a high density and may be reused.

Synthesis and characterization of MoB{sub 2−x} thin films grown by nonreactive DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Malinovskis, Paulius, E-mail: paulius.malinovskis@kemi.uu.se; Lewin, Erik; Jansson, Ulf [Department of Chemistry–Ångström Laboratory, Uppsala University, SE-751 21 Uppsala (Sweden); Palisaitis, Justinas; Persson, Per O. Å. [Department of Physics, Chemistry, and Biology (IFM), Thin Film Physics Division, Linköping University, SE-581 83 Linköping (Sweden)

2016-05-15

DC magnetron sputtering was used to deposit molybdenum boride thin films for potential low-friction applications. The films exhibit a nanocomposite structure with ∼10 nm large MoB{sub 2−x} (x > 0.4) grains surrounded by a boron-rich tissue phase. The preferred formation of the metastable and substoichiometric hP3-MoB{sub 2} structure (AlB{sub 2}-type) is explained with kinetic constraints to form the thermodynamically stable hR18-MoB{sub 2} phase with a very complex crystal structure. Nanoindentation revealed a relatively high hardness of (29 ± 2) GPa, which is higher than bulk samples. The high hardness can be explained by a hardening effect associated with the nanocomposite microstructure where the surrounding tissue phase restricts dislocation movement. A tribological study confirmed a significant formation of a tribofilm consisting of molybdenum oxide and boron oxide, however, without any lubricating effects at room temperature.

Intrinsic ZnO films fabricated by DC sputtering from oxygen-deficient targets for Cu(In,Ga)Se2 solar cell application

Institute of Scientific and Technical Information of China (English)

Chongyin Yang; DongyunWan; Zhou Wang; Fuqiang Huang

2011-01-01

Intrinsic zinc oxide films, normally deposited by radio frequency (RF) sputtering, are fabricated by direct current (DC) sputtering. The oxygen-deficient targets are prepared via a newly developed double crucible method. The 800-nm-thick film obtaines significantly higher carrier mobility compareing with that of the 800-nm-thick ZnO film. This is achieved by the widely used RF sputtering, which favors the prevention of carrier recombination at the interfaces and reduction of the series resistance of solar cells. The optimal ZnO film is used in a Cu (In, Ga) Se2 (CIGS) solar cell with a high efficiency of 11.57%. This letter demonstrates that the insulating ZnO films can be deposited by DC sputtering from oxygen-deficient ZnO targets to lower the cost of thin film solar cells.%Intrinsic zinc oxide films,normally deposited by radio frequency (RF) sputtering,are fabricated by direct current (DC) sputtering.The oxygen-deficient targets are prepared via a newly developed double crucible method.The 800-nm-thick film obtaines significantly higher carrier mobility compareing with that of the 800-nm-thick ZnO film.This is achieved by the widely used RF sputtering,which favors the prevention of carrier recombination at the interfaces and reduction of the series resistance of solar cells.The optimal ZnO film is used in a Cu (In,Ga) Se2 (C1GS) solar cell with a high efficiency of 11.57％.This letter demonstrates that the insulating ZnO films can be deposited by DC sputtering from oxygen-deficient ZnO targets to lower the cost of thin film solar cells.High resistance transparent intrinsic zinc oxide (i-ZnO)thin film has been widely nsed as the front electrode in transparent electronics and photovoltaic devices because of its low cost and nontoxicity.Owing to its unique characteristics of high transparency and adjustable resistivity in a certain range,the use of i-ZnO thin films as diffusion barrier layers of a-Si/μc-Si,CdTe,and CIGS thin-film solar cells has been advantageous

Low resistivity molybdenum thin film towards the back contact of dye ...

Indian Academy of Sciences (India)

Back contact; molybdenum; DC sputtering; dye-sensitized solar cell. 1. Introduction ... Structure and operation mechanism of a DSSC. Figure 2. Mo layers were .... to a better efficiency. In this work, the Mo thin films obtained by implying different.

Purely hopping conduction in c-axis oriented LiNbO3 thin films

Science.gov (United States)

Shandilya, Swati; Tomar, Monika; Sreenivas, K.; Gupta, Vinay

2009-05-01

Dielectric constant and ac conductivity of highly c-axis oriented LiNbO3 thin film grown by pulsed laser deposition were studied in a metal-insulator-metal configuration over a wide temperature (200 to 450 K) and frequency (100 Hz to 1 MHz) range. The preferred oriented Al (1%) doped ZnO film with electrical conductivity 1.1×103 Ω-1 cm-1 was deposited for dual purpose: (1) to serve as nucleating center for LiNbO3 crystallites along preferred c-axis growth direction, and (2) to act as a suitable bottom electrode for electrical studies. The room temperature dc conductivity (σdc) of LiNbO3 film was about 5.34×10-10 Ω-1 cm-1 with activation energy ˜0.3 eV, indicating extrinsic conduction. The ac conductivity σac was found to be much higher in comparison to σdc in the low temperature region (300 K), σac shows a weak frequency dependence, whereas dielectric constant exhibits a strong frequency dispersion. The dielectric dispersion data has been discussed in the light of theoretical models based on Debye type mixed conduction and purely hopping conduction. The dominant conduction in c-axis oriented LiNbO3 thin film is attributed to the purely hopping where both σdc and σac arise due to same mechanism.

Dry Etching Characteristics of Amorphous Indium-Gallium-Zinc-Oxide Thin Films

International Nuclear Information System (INIS)

Zheng Yanbin; Li Guang; Wang Wenlong; Li Xiuchang; Jiang Zhigang

2012-01-01

Amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) backplane technology is the best candidate for flat panel displays (FPDs). In this paper, a-IGZO TFT structures are described. The effects of etch parameters (rf power, dc-bias voltage and gas pressure) on the etch rate and etch profile are discussed. Three kinds of gas mixtures are compared in the dry etching process of a-IGZO thin films. Lastly, three problems are pointed out that need to be addressed in the dry etching process of a-IGZO TFTs. (plasma technology)

Direct-current substrate bias effects on amorphous silicon sputter-deposited films for thin film transistor fabrication

International Nuclear Information System (INIS)

Jun, Seung-Ik; Rack, Philip D.; McKnight, Timothy E.; Melechko, Anatoli V.; Simpson, Michael L.

2005-01-01

The effect that direct current (dc) substrate bias has on radio frequency-sputter-deposited amorphous silicon (a-Si) films has been investigated. The substrate bias produces a denser a-Si film with fewer defects compared to unbiased films. The reduced number of defects results in a higher resistivity because defect-mediated conduction paths are reduced. Thin film transistors (TFTs) that were completely sputter deposited were fabricated and characterized. The TFT with the biased a-Si film showed lower leakage (off-state) current, higher on/off current ratio, and higher transconductance (field effect mobility) than the TFT with the unbiased a-Si film

Nonlinear optical parameters of nanocrystalline AZO thin film measured at different substrate temperatures

Energy Technology Data Exchange (ETDEWEB)

Jilani, Asim, E-mail: asim.jilane@gmail.com [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-wahab, M.Sh [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni -Suef University, Beni-Suef (Egypt); Al-ghamdi, Attieh A. [Centre of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Dahlan, Ammar sadik [Department of architecture, faculty of environmental design, King Abdulaziz University, Jeddah (Saudi Arabia); Yahia, I.S. [Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Nano-Science & Semiconductor Labs, Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757 Cairo (Egypt)

2016-01-15

The 2.2 wt% of aluminum (Al)-doped zinc oxide (AZO) transparent and preferential c-axis oriented thin films were prepared by using radio frequency (DC/RF) magnetron sputtering at different substrate temperature ranging from room temperature to 200 °C. For structural analysis, X-ray Diffraction (XRD) and Atomic Force Electron Microscope (AFM) was used for morphological studies. The optical parameters such as, optical energy gap, refractive index, extinction coefficient, dielectric loss, tangent loss, first and third order nonlinear optical properties of transparent films were investigated. High transmittance above 90% and highly homogeneous surface were observed in all samples. The substrate temperature plays an important role to get the best transparent conductive oxide thin films. The substrate temperature at 150 °C showed the growth of highly transparent AZO thin film. Energy gap increased with the increased in substrate temperature of Al doped thin films. Dielectric constant and loss were found to be photon energy dependent with substrate temperature. The change in substrate temperature of Al doped thin films also affect the non-liner optical properties of thin films. The value of χ{sup (3)} was found to be changed with the grain size of the thin films that directly affected by the substrate temperature of the pure and Al doped ZnO thin films.

Synthesis of c-axis oriented AlN thin films on different substrates: A review

International Nuclear Information System (INIS)

Iriarte, G.F.; Rodriguez, J.G.; Calle, F.

2010-01-01

Highly c-axis oriented AlN thin films have been deposited by reactive sputtering on different substrates. The crystallographic properties of layered film structures consisting of a piezoelectric layer, aluminum nitride (AlN), synthesized on a variety of substrates, have been examined. Aluminum nitride thin films have been deposited by reactive pulsed-DC magnetron sputtering using an aluminum target in an Ar/N 2 gas mixture. The influence of the most critical deposition parameters on the AlN thin film crystallography has been investigated by means of X-ray diffraction (XRD) analysis of the rocking curve Full-Width at Half Maximum (FWHM) of the AlN-(0 0 0 2) peak. The relationship between the substrate, the synthesis parameters and the crystallographic orientation of the AlN thin films is discussed. A guide is provided showing how to optimize these conditions to obtain highly c-axis oriented AlN thin films on substrates of different nature.

Controlled formation of anatase and rutile TiO2 thin films by reactive magnetron sputtering

NARCIS (Netherlands)

Rafieian Boroujeni, Damon; Ogieglo, Wojciech; Savenije, Tom; Lammertink, Rob G.H.

2015-01-01

We discuss the formation of TiO2 thin films via DC reactive magnetron sputtering. The oxygen concentration during sputtering proved to be a crucial parameter with respect to the final film structure and properties. The initial deposition provided amorphous films that crystallise upon annealing to

Structural phototransformation of WO{sub 3} thin films detected by photoacoustic analysis

Energy Technology Data Exchange (ETDEWEB)

Pacheco, Argelia Perez, E-mail: ekargy@hotmail.com [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico); Montes de Oca, C. Oliva; Castaneda-Guzman, R.; Garcia, A. Esparza [Universidad Nacional Autonoma de Mexico, Laboratorio de Fotofisica y Peliculas Delgadas-CCADET, Ciudad Universitaria, Coyoacan, A.P. 70-186, C.P. 04510, Mexico, D.F. (Mexico)

2012-11-15

Highlights: Black-Right-Pointing-Pointer The phototransformation of WO{sub 3} thin films were studied by photoacoustic technique. Black-Right-Pointing-Pointer The phase transition in WO{sub 3} thin films was induced by laser irradiation fluence. Black-Right-Pointing-Pointer The onset and end of the phototransformation in the thin films was identified. Black-Right-Pointing-Pointer The ablation threshold for each sample was identified. - Abstract: The photoacoustic technique (PA) was used to detect the phase transformation from amorphous to crystalline state of tungsten oxide (WO{sub 3}) thin films induced by UV pulsed laser radiation at low energy (<1.5 mJ). The evolution of photoacoustic signal was studied by a correlation analysis, comparing successive signals at fluences ranging from 0 to 20 mJ/cm{sup 2}. In this interval, it was possible to observe structural changes and the ablation threshold in films due to incident laser fluence effect. Thin films of WO{sub 3} were deposited by DC reactive magnetron sputtering over glass substrates at different deposition times. The results obtained by correlation analysis were compared with Raman spectroscopy data.

Growth and characterization of textured YBaCo2O5+δ thin films grown on (001)-SrTiO3 via DC magnetron sputtering

International Nuclear Information System (INIS)

Galeano, V.; Arnache, O.; Supelano, I.; Vargas, C.A. Parra; Morán, O.

2016-01-01

Thin films of the layered cobaltite YBaCo 2 O 5+δ were successfully grown on (001)-oriented SrTiO 3 single-crystal substrates by means of DC magnetron sputtering. The 112 phase of the compound was stabilized by choosing an adequate Co reactant and through careful thermal treatment of the target. The results demonstrate the strong influence of these variables on the final phase of the compound. A substrate temperature of 1053 K and an oxygen pressure of 300 Pa seemed to be appropriate growing conditions for depositing (00ℓ)-textured YBaCo 2 O 5+δ thin films onto the chosen substrate. In like fashion to the polycrystalline YBaCo 2 O 5+δ , the films showed a clear sequence of antiferromagnetic–ferromagnetic–paramagnetic transitions within a narrow temperature range. Well-defined hysteresis loops were observed at temperatures as high as 270 K, which supports the existence of a FM order in the films. In turn, the dependence of the resistivity on the temperature shows a semiconductor-like behavior, without any distinguishable structure, within the temperature range measured (50–350 K). The analysis of the experimental data showed that the transport mechanism in the films is well described by using the Mott variable range hopping (VRH) conduction model. - Highlights: • YBaCo 2 O 5+δ thin films are grown on SrTiO 3 substrates. • Strong (00ℓ) reflections are observed in the X-ray diffraction pattern. • A clear sequence of magnetic transitions is observed. • Semiconducting-like behavior is verified.

Conductance Thin Film Model of Flexible Organic Thin Film Device using COMSOL Multiphysics

Science.gov (United States)

Carradero-Santiago, Carolyn; Vedrine-Pauléus, Josee

We developed a virtual model to analyze the electrical conductivity of multilayered thin films placed above a graphene conducting and flexible polyethylene terephthalate (PET) substrate. The organic layers of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a hole conducting layer, poly(3-hexylthiophene-2,5-diyl) (P3HT), as a p-type, phenyl-C61-butyric acid methyl ester (PCBM) and as n-type, with aluminum as a top conductor. COMSOL Multiphysics was the software we used to develop the virtual model to analyze potential variations and conductivity through the thin-film layers. COMSOL Multiphysics software allows simulation and modeling of physical phenomena represented by differential equations such as heat transfer, fluid flow, electromagnetism, and structural mechanics. In this work, using the AC/DC, electric currents module we defined the geometry of the model and properties for each of the six layers: PET/graphene/PEDOT:PSS/P3HT/PCBM/aluminum. We analyzed the model with varying thicknesses of graphene and active layers (P3HT/PCBM). This simulation allowed us to analyze the electrical conductivity, and visualize the model with varying voltage potential, or bias across the plates, useful for applications in solar cell devices.

High-frequency properties of superconducting Y-Ba-Cu-oxide thin films

International Nuclear Information System (INIS)

Ramakrishnan, E.S.; Su, M.; Howng, W.

1992-01-01

rf and microwave properties of superconducting YBa 2 Cu 3 O 7-x thin films were measured and analyzed using a coplanar resonator structure. The films were developed by sequential electron-beam evaporation of the metals followed by postanneal processing. dc properties of the films were obtained from resistance-temperature and current-voltage measurements to evaluate the transition temperature and current densities. High-frequency properties were measured from 70 to 10 K and in the frequency range 1--3 GHz to determine the film characteristics as compared to pure copper films on the same substrates

Magnetic studies of Fe-Y compositionally modulated thin films

International Nuclear Information System (INIS)

Badia, F.; Ferrater, C.; Lousa, A.; Martinez, B.; Labarta, A.; Tejada, J.

1990-01-01

Compositionally modulated thin films of Y/Fe have been studied by using SQUID magnetometry. Samples were grown by electron-beam evaporation onto Kapton substrates. In the low applied field regime, the samples show irreversible behavior when they are submitted to ZFC-FC magnetization processes, increasing the irreversibility zone as the thickness of the Fe layers increases. In the high applied magnetic field regime (H≥10 000 Oe), samples show ferromagnetic behavior. The temperature dependence of the saturation magnetization has been studied, and it was found that both spin-wave excitations and Stoner excitations occur at temperatures higher than 40 K, and a marked deviation from the T 3/2 law was noted below 30 K

Controlled formation of anatase and rutile TiO2 thin films by reactive magnetron sputtering

OpenAIRE

Rafieian Boroujeni, Damon; Ogieglo, Wojciech; Savenije, Tom; Lammertink, Rob G.H.

2015-01-01

We discuss the formation of TiO2 thin films via DC reactive magnetron sputtering. The oxygen concentration during sputtering proved to be a crucial parameter with respect to the final film structure and properties. The initial deposition provided amorphous films that crystallise upon annealing to anatase or rutile, depending on the initial sputtering conditions. Substoichiometric films (TiOx

Structural study and fabrication of nano-pattern on ultra thin film of Ag grown by magnetron sputtering

International Nuclear Information System (INIS)

Banerjee, S.; Mukherjee, S.; Kundu, S.

2001-01-01

We present the structural study of ultra thin Ag films using grazing incidence x-ray reflectivity and the modification of these films with the tip of an atomic force microscope. Ag thin films are deposited using dc magnetron sputtering on a Si(001) substrate. Initially, the growth of the film is carpet like and above a certain thickness (∼42 A) the film structure changes to form mounds. This ultra thin film of Ag having carpet-like growth can be modified by the tip of an atomic force microscope, which occurs due to the porous nature of the film. A periodic pattern of nanometer dimensions has been fabricated on this film using the atomic force microscope tip. (author)

Magnetic and structural study of Cu-doped TiO{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Torres, C.E. Rodriguez [Dpto de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina)], E-mail: torres@fisica.unlp.edu.ar; Golmar, F. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Cabrera, A.F.; Errico, L.; Navarro, A.M. Mudarra; Renteria, M.; Sanchez, F.H. [Dpto de Fisica-IFLP, Fac. Cs. Exactas, Universidad Nacional de La Plata-CONICET, CC 67, 1900 La Plata (Argentina); Duhalde, S. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina)

2007-10-31

Transparent pure and Cu-doped (2.5, 5 and 10 at.%) anatase TiO{sub 2} thin films were grown by pulsed laser deposition technique on LaAlO{sub 3} substrates. The samples were structurally characterized by X-ray absorption spectroscopy and X-ray diffraction. The magnetic properties were measured using a SQUID. All films have a FM-like behaviour. In the case of the Cu-doped samples, the magnetic cycles are almost independent of the Cu concentration. Cu atoms are forming CuO and/or substituting Ti in TiO{sub 2}. The thermal treatment in air promotes the CuO segregation. Since CuO is antiferromagnetic, the magnetic signals present in the films could be assigned to Cu substitutionally replacing cations in TiO{sub 2}.

Composition, structure and magnetic properties of sputter deposited Ni-Mn-Ga ferromagnetic shape memory thin films

Energy Technology Data Exchange (ETDEWEB)

Annadurai, A.; Nandakumar, A.K.; Jayakumar, S.; Kannan, M.D. [Thin Film Center, Department of Physics, PSG College of Technology, Coimbatore 641004 (India); Manivel Raja, M.; Bysak, S. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, Andhra Pradesh 500 058 (India); Gopalan, R. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, Andhra Pradesh 500 058 (India)], E-mail: rg_gopy@yahoo.com; Chandrasekaran, V. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, Andhra Pradesh 500 058 (India)

2009-03-15

Polycrystalline Ni-Mn-Ga thin films were deposited by the d.c. magnetron sputtering on well-cleaned substrates of Si(1 0 0) and glass at a constant sputtering power of 36 W. We report the influence of sputtering pressure on the composition, structure and magnetic properties of the sputtered thin films. These films display ferromagnetic behaviour only after annealing at an elevated temperature and a maximum saturation magnetization of 335 emu/cc was obtained for the films investigated. Evolution of martensitic microstructure was observed in the annealed thin films with the increase of sputtering pressure. The thermo-magnetic curves exhibited only magnetic transition in the temperature range of 339-374 K. The thin film deposited at high sputtering pressure of 0.025 mbar was found to be ordered L2{sub 1} austenitic phase.

Structural and biocompatible characterization of TiC/a:C nanocomposite thin films

International Nuclear Information System (INIS)

Balázsi, K.; Vandrovcová, M.; Bačáková, L.; Balázsi, Cs.

2013-01-01

In this work, sputtered TiC/amorphous C thin films have been developed in order to be applied as potential barrier coating for interfering of Ti ions from pure Ti or Ti alloy implants. Our experiments were based on magnetron sputtering method, because the vacuum deposition provides great flexibility for manipulating material chemistry and structure, leading to films and coatings with special properties. The films have been deposited on silicon (001) substrates with 300 nm thick oxidized silicon sublayer at 200 °C deposition temperature as model substrate. Transmission electron microscopy has been used for structural investigations. Thin films consisted of ∼ 20 nm TiC columnar crystals embedded by 5 nm thin amorphous carbon matrix. MG63 osteoblast cells have been applied for in vitro study of TiC nanocomposites. The cell culture tests give strong evidence of thin films biocompatibility. Highlights: ► The main goal of this work is the relatively easy preparation of nanocomposite TiC thin films by dc magnetron sputtering. ► TEM and HREM were applied for structural characterization of columnar TiC nanocrystals and amorphous carbon matrix. ► The biocompatibility of films was showed by MG63 human osteoblast like cells during 1, 3 and 7 days seeding

High-density plasma etching characteristics of indium-gallium-zinc oxide thin films in CF4/Ar plasma

International Nuclear Information System (INIS)

Joo, Young-Hee; Kim, Chang-Il

2015-01-01

We investigated the etching process of indium-gallium-zinc oxide (IGZO) thin films in an inductively coupled plasma system. The dry etching characteristics of the IGZO thin films were studied by varying the CF 4 /Ar gas mixing ratio, RF power, DC-bias voltage, and process pressure. We determined the following optimized process conditions: an RF power of 700 W, a DC-bias voltage of − 150 V, and a process pressure of 2 Pa. A maximum etch rate of 25.63 nm/min for the IGZO thin films was achieved in a plasma with CF 4 /Ar(= 25:75), and the selectivity of IGZO to Al and TiN was found to be 1.3 and 0.7, respectively. We determined the ionic composition of the CF 4 /Ar plasma using optical emission spectroscopy. Analysis of chemical reactions at the IGZO thin film surfaces was performed using X-ray photoelectron spectroscopy. - Highlights: • IGZO thin film was etched by CF 4 /Ar plasma as a function of gas mixing ratio. • IGZO bonds were broken Ar + sputtering and then reacted with the C-F x radicals. • The physical sputtering is dominant in etch control compared with chemical etching

Solid thin film materials for use in thin film charge-coupled devices

International Nuclear Information System (INIS)

Lynch, S.J.

1983-01-01

Solid thin films deposited by vacuum deposition were evaluated to ascertain their effectiveness for use in the manufacturing of charge-coupled devices (CCDs). Optical and electrical characteristics of tellurium and Bi 2 Te 3 solid thin films were obtained in order to design and to simulate successfully the operation of thin film (TF) CCDs. In this article some of the material differences between single-crystal material and the island-structured thin film used in TFCCDs are discussed. The electrical parameters were obtained and tabulated, e.g. the mobility, conductivity, dielectric constants, permittivity, lifetime of holes and electrons in the thin films and drift diffusion constants. The optical parameters were also measured and analyzed. After the design was complete, experimental TFCCDs were manufactured and were successfully operated utilizing the aforementioned solid thin films. (Auth.)

Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

OpenAIRE

Deepak Kumar Kaushik; K. Uday Kumar; A. Subrahmanyam

2017-01-01

Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l ...

Effect of a Ga-doped ZnO thin film with a ZTO buffer layer fabricated by using pulsed DC magnetron sputter for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Song, Sang-Woo; Lee, Kyung-Ju; Roh, Ji-Hyung; Park, On-Jeon; Kim, Hwan-Sun; Moon, Byung-Moo [Korea University, Seoul (Korea, Republic of); Ji, Min-Woo [Yonsei University, Seoul (Korea, Republic of)

2014-08-15

The electrical property of a Ga-doped ZnO(GZO) thin film is well known to be similar that of commercialized fluorine-doped tin oxide(FTO). However GZO is limited for use at high process temperatures for solar cells because of its unstable resistivity at temperatures above 300 .deg. C. A GZO thin film compared to zinc tin oxide(ZTO)-GZO multilayer can be used at high process temperatures. A GZO thin film was deposited on glass by using pulsed DC magnetron sputter. Then, a ZTO buffer layer was deposited on the GZO surface. During the deposition, the working pressure was 5 mTorr (Z-1 glass) and 1 mTorr (Z-2 glass). Dye-sensitized solar cells (DSSCs) were fabricated using Z-1, Z-2 and commercialized FTO glasses. Z-2 showed a conversion efficiency of 4.265%, which was enhanced by 0.399% compared to that of the DSSCs using FTO(3.784%). The conversion efficiency for Z-1 (3.889%) was a little higher than that of FTO. Thus, the ZTO-GZO electrode showed better characteristics than those obtained using the FTO electrode, which can be attributed to the reduced charge recombination and series resistance.

Growth, structure and magnetic properties of magnetron sputtered FePt thin films

Energy Technology Data Exchange (ETDEWEB)

Cantelli, Valentina

2010-07-01

The L1{sub 0} FePt phase belongs to the most promising hard ferromagnetic materials for high density recording media. The main challenges for thin FePt films are: (i) to lower the process temperature for the transition from the soft magnetic A1 to the hard magnetic L1{sub 0} phase, (ii) to realize c-axes preferential oriented layers independently from the substrate nature and (iii) to control layer morphology supporting the formation of FePt-L1{sub 0} selforganized isolated nanoislands towards an increase of the signal-to-noise ratio. In this study, dc magnetron sputtered FePt thin films on amorphous substrates were investigated. The work is focused on the correlation between structural and magnetic properties with respect to the influence of deposition parameters like growth mode (cosputtering vs. layer - by - layer) and the variation of the deposition gas (Ar, Xe) or pressure (0.3-3 Pa). In low-pressure Ar discharges, high energetic particle impacts support vacancies formation during layer growth lowering the phase transition temperature to (320{+-}20) C. By reducing the particle kinetic energy in Xe discharges, highly (001) preferential oriented L1{sub 0}-FePt films were obtained on a-SiO{sub 2} after vacuum annealing. L1{sub 0}-FePt nano-island formation was supported by the introduction of an Ag matrix, or by random ballistic aggregation and atomic self shadowing realized by FePt depositions at very high pressure (3 Pa). The high coercivity (1.5 T) of granular, magnetic isotropic FePt layers, deposited in Ar discharges, was measured with SQUID magnetometer hysteresis loops. For non-granular films with (001) preferential orientation the coercivity decreased (0.6 T) together with an enhancement of the out-of- plane anisotropy. Nanoislands show a coercive field close to the values obtained for granular layers but exhibit an in-plane easy axis due to shape anisotropy effects. An extensive study with different synchrotron X-ray scattering techniques, mainly

Thin-film photovoltaic technology

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, R.N. [National Renewable Energy Laboratory, Golden, CO (United States)

2010-07-01

The high material and processing costs associated with single-crystal and polycrystalline silicon wafers that are commonly used in photovoltaic cells render these modules expensive. This presentation described thin-film solar cell technology as a promising alternative to silicon solar cell technology. Cadmium telluride (CdTe) thin films along with copper, indium, gallium, and selenium (CIGS) thin films have become the leaders in this field. Their large optical absorption coefficient can be attributed to a direct energy gap that allows the use of thin layers (1-2 {mu}m) of active material. The efficiency of thin-film solar cell devices based on CIGS is 20 per cent, compared to 16.7 per cent for thin-film solar cell devices based on CdTe. IBM recently reported an efficiency of 9.7 per cent for a new type of inorganic thin-film solar cell based on a Cu{sub 2}ZnSn(S, Se){sub 4} compound. The efficiency of an organic thin-film solar cell is 7.9 per cent. This presentation included a graph of PV device efficiencies and discussed technological advances in non-vacuum deposited, CIGS-based thin-film solar cells. 1 fig.

Advanced properties of Al-doped ZnO films with a seed layer approach for industrial thin film photovoltaic application

International Nuclear Information System (INIS)

Dewald, Wilma; Sittinger, Volker; Szyszka, Bernd; Säuberlich, Frank; Stannowski, Bernd; Köhl, Dominik; Ries, Patrick; Wuttig, Matthias

2013-01-01

Currently sputtered Al-doped ZnO films are transferred to industry for the application in thin film silicon solar modules. These films are known to easily form light trapping structures upon etching which are necessary for absorbers with low absorbance such as μc-Si. Up to now the best structures for high efficiency thin film silicon solar cells were obtained by low rate radio frequency (r.f.) sputtering of ceramic targets. However, for industrial application a high rate process is essential. Therefore a seed layer approach was developed to increase the deposition rate while keeping the desired etch morphology and electrical properties. Aluminum doped ZnO films were deposited dynamically by direct current (d.c.) magnetron sputtering from a ceramic ZnO:Al 2 O 3 target (1 wt.%) onto an additional seed layer prepared by r.f. sputtering. ZnO:Al films were investigated with respect to their optical and electrical properties as well as the morphology created after etching for a-Si/μc-Si solar cells. Additionally atomic force microscopy, scanning electron microscopy, X-ray diffraction and Hall measurements were performed, comparing purely r.f. or d.c. sputtered films with d.c. sputtered films on seed layers. With the seed layer approach it was possible to deposit ZnO:Al films with a visual transmittance of 83.5%, resistivity of 295 μΩ cm, electron mobility of 48.9 cm 2 /Vs and electron density of 4.3 · 10 20 cm −3 from a ceramic target at 330 °C. Etch morphologies with 1 μm lateral structure size were achieved. - Highlights: ► Seed layer approach for dynamic sputter deposition of enhanced quality ZnO:Al. ► A thin radio frequency sputtered ZnO:Al layer assists film nucleation on glass. ► Electron mobility was increased up to 49 cm 2 /Vs due to quasi-epitaxial film growth. ► Etch morphology exhibits 1 μm wide craters for light trapping in solar cells. ► The concept was transferred to a seed layer sputtered with direct current

Advanced properties of Al-doped ZnO films with a seed layer approach for industrial thin film photovoltaic application

Energy Technology Data Exchange (ETDEWEB)

Dewald, Wilma, E-mail: wilma.dewald@ist.fraunhofer.de [Fraunhofer Institute for Surface Engineering and Thin Films IST, Bienroder Weg 54E, 38108 Braunschweig (Germany); Sittinger, Volker; Szyszka, Bernd [Fraunhofer Institute for Surface Engineering and Thin Films IST, Bienroder Weg 54E, 38108 Braunschweig (Germany); Säuberlich, Frank; Stannowski, Bernd [Sontor GmbH, OT Thalheim, Sonnenallee 7-11, 06766 Bitterfeld-Wolfen (Germany); Köhl, Dominik; Ries, Patrick; Wuttig, Matthias [I. Physikalisches Institut (IA), RWTH Aachen, Sommerfeldstraße 14, 52074 Aachen (Germany)

2013-05-01

Currently sputtered Al-doped ZnO films are transferred to industry for the application in thin film silicon solar modules. These films are known to easily form light trapping structures upon etching which are necessary for absorbers with low absorbance such as μc-Si. Up to now the best structures for high efficiency thin film silicon solar cells were obtained by low rate radio frequency (r.f.) sputtering of ceramic targets. However, for industrial application a high rate process is essential. Therefore a seed layer approach was developed to increase the deposition rate while keeping the desired etch morphology and electrical properties. Aluminum doped ZnO films were deposited dynamically by direct current (d.c.) magnetron sputtering from a ceramic ZnO:Al{sub 2}O{sub 3} target (1 wt.%) onto an additional seed layer prepared by r.f. sputtering. ZnO:Al films were investigated with respect to their optical and electrical properties as well as the morphology created after etching for a-Si/μc-Si solar cells. Additionally atomic force microscopy, scanning electron microscopy, X-ray diffraction and Hall measurements were performed, comparing purely r.f. or d.c. sputtered films with d.c. sputtered films on seed layers. With the seed layer approach it was possible to deposit ZnO:Al films with a visual transmittance of 83.5%, resistivity of 295 μΩ cm, electron mobility of 48.9 cm{sup 2}/Vs and electron density of 4.3 · 10{sup 20} cm{sup −3} from a ceramic target at 330 °C. Etch morphologies with 1 μm lateral structure size were achieved. - Highlights: ► Seed layer approach for dynamic sputter deposition of enhanced quality ZnO:Al. ► A thin radio frequency sputtered ZnO:Al layer assists film nucleation on glass. ► Electron mobility was increased up to 49 cm{sup 2}/Vs due to quasi-epitaxial film growth. ► Etch morphology exhibits 1 μm wide craters for light trapping in solar cells. ► The concept was transferred to a seed layer sputtered with direct current.

Enhanced properties of tungsten thin films deposited with a novel HiPIMS approach

Science.gov (United States)

Velicu, Ioana-Laura; Tiron, Vasile; Porosnicu, Corneliu; Burducea, Ion; Lupu, Nicoleta; Stoian, George; Popa, Gheorghe; Munteanu, Daniel

2017-12-01

Despite the tremendous potential for industrial use of tungsten (W), very few studies have been reported so far on controlling and tailoring the properties of W thin films obtained by physical vapor deposition techniques and, even less, for those deposited by High Power Impulse Magnetron Sputtering (HiPIMS). This study presents results on the deposition process and properties characterization of nanocrystalline W thin films deposited on silicon and molybdenum substrates (100 W average sputtering power) by conventional dc magnetron sputtering (dcMS) and HiPIMS techniques. Topological, structural, mechanical and tribological properties of the deposited thin films were investigated. It was found that in HiPIMS, both deposition process and coatings properties may be optimized by using an appropriate magnetic field configuration and pulsing design. Compared to the other deposited samples, the W films grown in multi-pulse (5 × 3 μs) HiPIMS assisted by an additional magnetic field, created with a toroidal-shaped permanent magnet placed in front of the magnetron cathode, show significantly enhanced properties, such as: smoother surfaces, higher homogeneity and denser microstructure, higher hardness and Young's modulus values, better adhesion to the silicon substrate and lower coefficient of friction. Mechanical behaviour and structural changes are discussed based on plasma diagnostics results.

Annealing dependence of residual stress and optical properties of TiO2 thin film deposited by different deposition methods.

Science.gov (United States)

Chen, Hsi-Chao; Lee, Kuan-Shiang; Lee, Cheng-Chung

2008-05-01

Titanium oxide (TiO(2)) thin films were prepared by different deposition methods. The methods were E-gun evaporation with ion-assisted deposition (IAD), radio-frequency (RF) ion-beam sputtering, and direct current (DC) magnetron sputtering. Residual stress was released after annealing the films deposited by RF ion-beam or DC magnetron sputtering but not evaporation, and the extinction coefficient varied significantly. The surface roughness of the evaporated films exceeded that of both sputtered films. At the annealing temperature of 300 degrees C, anatase crystallization occurred in evaporated film but not in the RF ion-beam or DC magnetron-sputtered films. TiO(2) films deposited by sputtering were generally more stable during annealing than those deposited by evaporation.

Influence of stress on the structural and dielectric properties of rf magnetron sputtered zinc oxide thin film

Science.gov (United States)

Menon, Rashmi; Sreenivas, K.; Gupta, Vinay

2008-05-01

Highly c axis oriented zinc oxide (ZnO) thin films have been prepared on 1737 Corning glass substrate by planar rf magnetron sputtering under varying pressure (10-50mTorr) and different oxygen percentage (40%-100%) in reactive gas mixtures. The as-grown ZnO thin films were found to have stress over a wide range from -6×1010to-9×107dynes/cm2. The presence of stress depends strongly on processing conditions, and films become almost stress free under a unique combination of sputtering pressure and reactive gas composition. The studies show a correlation of stress with structural and electrical properties of the ZnO thin film. The stressed films possess high electrical conductivity and exhibits strong dielectric dispersion over a wide frequency (1kHz-1MHz). The dielectric constant ɛ'(ω) of stress free ZnO film was almost frequency independent and was close to the bulk value. The measured value of dc conductivity, σdc(ω) and ac conductivity σac(ω) of stress free ZnO film was 1.3×10-9 and 6.8×10-5Ω-1cm-1, respectively. The observed variation in the structural and electrical properties of ZnO thin film with stress has been analyzed in the light of growth kinetics.

Thin film processes II

CERN Document Server

Kern, Werner

1991-01-01

This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

An optimized In–CuGa metallic precursors for chalcopyrite thin films

Energy Technology Data Exchange (ETDEWEB)

Han, Jun-feng, E-mail: junfeng.han@cnrs-imn.fr [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Department of Physics, Peking University, Beijing 100871 (China); Liao, Cheng [Department of Physics, Peking University, Beijing 100871 (China); Chengdu Green Energy and Green Manufacturing Technology R and D Center, Chengdu, Sichuan Province 601207 (China); Jiang, Tao; Xie, Hua-mu; Zhao, Kui [Department of Physics, Peking University, Beijing 100871 (China); Besland, M.-P. [Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France)

2013-10-31

We report a study of CuGa–In metallic precursors for chalcopyrite thin film. CuGa and In thin films were prepared by DC sputtering at room temperature. Due to low melting point of indium, the sputtering power on indium target was optimized. Then, CuGa and In multilayers were annealed at low temperature. At 120 °C, the annealing treatment could enhance diffusion and alloying of CuGa and In layers; however, at 160 °C, it caused a cohesion and crystalline of indium from the alloy which consequently formed irregular nodules on the film surface. The precursors were selenized to form copper indium gallium selenide (CIGS) thin films. The morphological and structural properties were investigated by scanning electron microscopy, X-ray diffraction and Raman spectra. The relationships between metallic precursors and CIGS films were discussed in the paper. A smooth precursor layer was the key factor to obtain a homogeneous and compact CIGS film. - Highlights: • An optimized sputtered indium film • An optimized alloying process of metallic precursor • An observation of nodules forming on the indium film and precursor surface • An observation of cauliflower structure in copper indium gallium selenide film • The relationship between precursor and CIGS film surface morphology.

Detection of nuclear magnetic resonance in the microtesla range using a high Tc dc-SQUID

International Nuclear Information System (INIS)

Wang Ning; Jin Yirong; Li Shao; Ren Yufeng; Tian Ye; Chen Yingfei; Li Jie; Chen Genghua; Zheng Dongning

2012-01-01

We have detected the ultra-low field nuclear magnetic resonance signal from water samples using a high-T c dc-SQUID sensor. The measurements were carried out in a homemade magnetically shielded room. Resonance spectra of 1 H from tap water and other substance samples were obtained in the field range from 7-110μT corresponding to resonance frequency 300-4.68kHz. Two kind of experimental systems were built, the first one is a directly coupled system, its signal to noise ratio in a single-shot measurement is around 4 for about 15 ml water. The second one used a Cu coil to transfer the flux to the SQUID sensor. Signal to noise ratio was improved to about 20 in a single-shot measurement for 5ml water, which benefits from the improvement of coupling efficiency. The effect of residual gradient in the magnetically shielded room was also investigated. J-coupling of 2,2,2-Trifluoroethyl alcohol was measured, the peaks are consistent with high field results.

Detection of nuclear magnetic resonance in the microtesla range using a high Tc dc-SQUID

Science.gov (United States)

Wang, Ning; Jin, Yirong; Li, Shao; Ren, Yufeng; Tian, Ye; Chen, Yingfei; Li, Jie; Chen, Genghua; Zheng, Dongning

2012-12-01

We have detected the ultra-low field nuclear magnetic resonance signal from water samples using a high-Tc dc-SQUID sensor. The measurements were carried out in a homemade magnetically shielded room. Resonance spectra of 1H from tap water and other substance samples were obtained in the field range from 7-110μT corresponding to resonance frequency 300-4.68kHz. Two kind of experimental systems were built, the first one is a directly coupled system, its signal to noise ratio in a single-shot measurement is around 4 for about 15 ml water. The second one used a Cu coil to transfer the flux to the SQUID sensor. Signal to noise ratio was improved to about 20 in a single-shot measurement for 5ml water, which benefits from the improvement of coupling efficiency. The effect of residual gradient in the magnetically shielded room was also investigated. J-coupling of 2,2,2-Trifluoroethyl alcohol was measured, the peaks are consistent with high field results.

Investigation of plasma dynamics during the growth of amorphous titanium dioxide thin films

Science.gov (United States)

Kim, Jin-Soo; Jee, Hyeok; Yu, Young-Hun; Seo, Hye-Won

2018-06-01

We have grown amorphous titanium dioxide thin films by reactive DC sputtering method using a different argon/oxygen partial pressure at a room temperature. The plasma dynamics of the process, reactive and sputtered gas particles was investigated via optical emission spectroscopy. We then studied the correlations between the plasma states and the structural/optical properties of the films. The growth rate and morphology of the titanium dioxide thin films turned out to be contingent with the population and the energy profile of Ar, O, and TiO plasma. In particular, the films grown under energetic TiO plasma have shown a direct band-to-band transition with an optical energy band gap up to ∼4.2 eV.

Characterization of Ag-doped vanadium oxide (AgxV2O5) thin film for cathode of thin film battery

International Nuclear Information System (INIS)

Hwang, H.S.; Oh, S.H.; Kim, H.S.; Cho, W.I.; Cho, B.W.; Lee, D.Y.

2004-01-01

The effect of silver co-sputtering on the characteristics of amorphous V 2 O 5 films, grown by dc reactive sputtering, is investigated. The co-sputtering process influences the growth mechanism as well as the characteristics of the V 2 O 5 films. X-ray diffraction (XRD), Inductively coupled plasma-atomic emission spectrometry (ICP-AES), field emission-scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FT-IR) and X-ray photoelectron spectrometry (XPS) results indicate that the microstructure of the V 2 O 5 films is affected by the rf power of the co-sputtered silver. In addition, an all-solid-state thin film battery with full cell structure of Li/LiPON/Ag x V 2 O 5 /Pt has been fabricated. It is found that the silver co-sputtered V 2 O 5 cathode film exhibits better cycle performance than an undoped one

High-density plasma etching characteristics of indium-gallium-zinc oxide thin films in CF{sub 4}/Ar plasma

Energy Technology Data Exchange (ETDEWEB)

Joo, Young-Hee; Kim, Chang-Il

2015-05-29

We investigated the etching process of indium-gallium-zinc oxide (IGZO) thin films in an inductively coupled plasma system. The dry etching characteristics of the IGZO thin films were studied by varying the CF{sub 4}/Ar gas mixing ratio, RF power, DC-bias voltage, and process pressure. We determined the following optimized process conditions: an RF power of 700 W, a DC-bias voltage of − 150 V, and a process pressure of 2 Pa. A maximum etch rate of 25.63 nm/min for the IGZO thin films was achieved in a plasma with CF{sub 4}/Ar(= 25:75), and the selectivity of IGZO to Al and TiN was found to be 1.3 and 0.7, respectively. We determined the ionic composition of the CF{sub 4}/Ar plasma using optical emission spectroscopy. Analysis of chemical reactions at the IGZO thin film surfaces was performed using X-ray photoelectron spectroscopy. - Highlights: • IGZO thin film was etched by CF{sub 4}/Ar plasma as a function of gas mixing ratio. • IGZO bonds were broken Ar{sup +} sputtering and then reacted with the C-F{sub x} radicals. • The physical sputtering is dominant in etch control compared with chemical etching.

Investigation of corrosion behavior of nitrogen doped and platinum/ruthenium doped diamond-like carbon thin films in Hank's solution

International Nuclear Information System (INIS)

Khun, N.W.; Liu, E.

2011-01-01

Undoped (DLC), nitrogen-doped (N-DLC) and platinum/ruthenium doped diamond-like carbon (PtRu-DLC) thin films were deposited on p-Si (100) substrates using a DC magnetron sputtering deposition system. The chemical composition, bonding structure, surface morphology and adhesion strength of the films were characterized using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch test, respectively. The corrosion behavior of the films in a Hank's solution was investigated using potentiodynamic polarization test. The corrosion results revealed that the PtRu-DLC film had the highest corrosion potential among the films used in this study. Highlights: → DLC thin films were deposited on Si substrates via dc magnetron sputtering. → Some DLC films were doped with N and/or Pt/Ru. → The film corrosion behavior was studied in a Hank solution with polarization test. → The PtRu-DLC film showed the highest corrosion potential among the films studied.

Effect of substrate on texture and mechanical properties of Mg-Cu-Zn thin films

Science.gov (United States)

Eshaghi, F.; Zolanvari, A.

2018-04-01

In this work, thin films of Mg-Cu-Zn with 60 nm thicknesses have been deposited on the Si(100), Al, stainless steel, and Cu substrates using DC magnetron sputtering. FESEM images displayed uniformity of Mg-Cu-Zn particles on the different substrates. AFM micrograph revealed the roughness of thin film changes due to the different kinds of the substrates. XRD measurements showed the existence of strong Mg (002) reflections and weak Mg (101) peaks. Residual stress and adhesion force have been measured as the mechanical properties of the Mg-Cu-Zn thin films. The residual stresses of thin films which have been investigated by X-ray diffraction method revealed that the thin films sputtered on the Si and Cu substrates endure minimum and maximum stresses, respectively, during the deposition process. However, the force spectroscopy analysis indicated that the films grew on the Si and Cu experienced maximum and minimum adhesion force. The texture analysis has been done using XRD instrument to make pole figures of Mg (002) and Mg (101) reflections. ODFs have been calculated to evaluate the distribution of the orientations within the thin films. It was found that the texture and stress have an inverse relation, while the texture and the adhesion force of the Mg-Cu-Zn thin films have direct relation. A thin film that sustains the lowest residual stresses and highest adhesive force had the strongest {001} basal fiber texture.

Highly transparent and conductive thin films fabricated with nano-silver/double-walled carbon nanotube composites.

Science.gov (United States)

Lee, Shie-Heng; Teng, Chih-Chun; Ma, Chen-Chi M; Wang, Ikai

2011-12-01

This study develops a technique for enhancing the electrical conductivity and optical transmittance of transparent double-walled carbon nanotube (DWNT) film. Silver nanoparticles were modified with a NH(2)(CH(2))(2)SH self-assembled monolayer terminated by amino groups and subsequent surface condensation that reacted with functionalized DWNTs. Ag nanoparticles were grafted on the surface of the DWNTs. The low sheet resistance of the resulting thin conductive film on a polyethylene terephthalate (PET) substrate was due to the increased contact areas between DWNTs and work function by grafting Ag nanoparticles on the DWNT surfaces. Increasing the contact area between DWNTs and work function improved the conductivity of the DWNT-Ag thin films. The prepared DWNT-Ag thin films had a sheet resistance of 53.4 Ω/sq with 90.5% optical transmittance at a 550 nm wavelength. After treatment with HNO(3) and annealing at 150 °C for 30 min, a lower sheet resistance of 45.8 Ω/sq and a higher transmittance of 90.4% could be attained. The value of the DC conductivity to optical conductivity (σ(DC)/σ(OP)) ratio is 121.3. Copyright © 2011 Elsevier Inc. All rights reserved.

Pyrolyzed thin film carbon

Science.gov (United States)

Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

2010-01-01

A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

Nuclear magnetic resonance with dc SQUID [Super-conducting QUantum Interference Device] preamplifiers

International Nuclear Information System (INIS)

Fan, N.Q.; Heaney, M.B.; Clark, J.; Newitt, D.; Wald, L.; Hahn, E.L.; Bierlecki, A.; Pines, A.

1988-08-01

Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by 35 Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10 16 nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing 35 Cl nuclei was placed in a capacitor and the signal detected electrically using a tuned SQUID amplifier and Q-spoiler. In this way, the electrical polarization induced by the precessing Cl nuclear quadrupole moments was detected: this is the inverse of the Stark effect in NQR. Two experiments involving NMR have been carried out. In the first, the 30 MHz resonance in 119 Sn nuclei is detected with a tuned amplifier and Q-spoiler, and a single pulse resolution of 10 18 nuclear Bohr magnetons in a bandwidth of 25 kHz has been achieved. For the second, a low frequency NMR system has been developed that uses an untuned input circuit coupled to the SQUID. The resonance in 195 Pt nuclei has been observed at 55 kHz in a field of 60 gauss. 23 refs., 11 figs

thin films

Indian Academy of Sciences (India)

microscopy (SEM) studies, respectively. The Fourier transform ... Thin films; chemical synthesis; hydrous tin oxide; FTIR; electrical properties. 1. Introduction ... dehydrogenation of organic compounds (Hattori et al 1987). .... SEM images of (a) bare stainless steel and (b) SnO2:H2O thin film on stainless steel substrate at a ...

TEM investigation of DC sputtered carbon-nitride-nickel thin films

International Nuclear Information System (INIS)

Safran, G.; Geszti, O.; Radnoczi, G.

2002-01-01

Deposition of carbon nitride (C-N) and carbon-nitride-nickel (C-N-Ni) films onto glass, NaCl and Si(001) substrates was carried out in a dc magnetron sputtering system. Carbon was deposited from high-purity (99.99%) pyrolytic graphite target, 50 mm in diameter, positioned at 10 cm from a resistance-heated substrate holder. C-N-Ni films were grown by a small Ni plate mounted on the graphite target. The base pressure of the deposition chamber was ∼7x10 -7 Torr. Films were grown at a substrate temperature of 20-700 grad C, in pure N 2 at partial pressures of 1.9 -2.2 mTorr and the substrates were held at ground potential. The typical film thickness of 15-30 nm was deposited on all the substrates at a magnetron current of 0.2 and 0.3 A, which resulted in a deposition rate of 1.5-2 nm/s. Structural characterizations were performed by high-resolution transmission electron microscopy (HRTEM) using a JEOL 3010 operated at 300 kV and a 200 kV Philips CM 20 electron microscope equipped with a Ge detector Noran EDS system. The N content of the C-N samples prepared at room temperature was 22-24% by EDS measurement and showed a decrease to 6-7% at elevated temperatures up to 700 grad C. The N concentration in the C-N-Ni films was higher: ∼38% at RT and ∼9% at 700 grad C. The Ni concentration of C-N-Ni samples was 5-6% and 0.3-0.4% in samples deposited at RT and 700 grad C respectively. The low Ni content in the latter is attributed to a decrease of the sticking coefficient of the carbon co-deposited Ni at elevated temperatures. (Authors)

Microstructure and opto-electric properties of Cu/ITO thin films

International Nuclear Information System (INIS)

Wang Xian; Li Junlei; Shi Shiwei; Song Xueping; Cui Jingbiao; Sun Zhaoqi

2012-01-01

Highlights: ► We prepared Cu/ITO films with different Cu layer thickness. ► We analyzed the relation between opto-electric properties and roughness of the films. ► The Cu-16.1 nm/ITO film shows excellent optical and electric properties. ► Cu/ITO films have great application prospects in new-type transflective displays. - Abstract: Cu/ITO thin films were deposited on glass and silicon substrates by DC and RF magnetron sputtering at room temperature. X-ray diffraction results showed that the films were amorphous. Both of SEM images and 3D Profilometer images indicated that the surface morphology of the ITO films had been affected by the Cu layer. The optical and electric properties of the Cu/ITO films changed significantly with the variation of Cu layer thickness. Cu-5.4 nm/ITO film exhibited the highest optical transmittance of 62.9% at 550 nm and the lowest sheet resistance of 96 Ω/□, whereas Cu-16.1 nm/ITO film showed the highest average reflectance of 24.0% and the lowest resistance of 27.4 Ω/□. Based on our analysis, it was evaluated that Cu layer had an important effect on the electrical and optical properties of ITO thin films.

Vacuum Pumping Performance Comparison of Non-Evaporable Getter Thin Films Deposited Using Argon and Krypton as Sputtering Gases

CERN Document Server

Liu, Xianghong; He, Yun; Li, Yulin

2005-01-01

Owing to the outstanding vacuum performance and the low secondary electron yield, non-evaporable getter (NEG) thin film deposited onto interior walls has gained widespread acceptance and has been incorporated into many accelerator vacuum system designs. The titanium-zirconium-vanadium (T-Zr-V) NEG thin films were deposited onto the interior wall of stainless steel pipes via DC magnetron sputtering method using either argon or krypton gas as sputtering gas. Vacuum pumping evaluation tests were carried out to compare vacuum pumping performances of the Ti-Zr-V NEG thin films deposited using argon or krypton. The results showed much higher initial pumping speed for the Kr-sputtered NEG film than the Ar-sputtered film, though both films have similar activation behavior. The compositions and textures of both thin films were measured to correlate to the pumping performances.

Mapping of Ambient Magnetic Fields within Liquid Helium Dewar for Testing of a DC SQUID Magnetometer

International Nuclear Information System (INIS)

Newhouse, Randal

2003-01-01

In an effort to explore the cavity lights phenomenon, Experimental Facilities Department at SLAC is testing a DC SQUID magnetometer. Due to the nature of the SQUID magnetometer and the intended tests, the earth's magnetic field must be negated. It is proposed to reduce ambient fields using bucking coils. First, however, an accurate map of the magnetic field inside the liquid helium Dewar where the experiment is going to take place needed to be made. This map was made using a three-axis fluxgate magnetometer mounted on a 3D positioning device made for this purpose. A ten inch tall volume within the Dewar was measured at data points approximately an inch from each other in all three axes. A LabVEIW program took readings from the magnetometer at 2 ms intervals for 1000 readings in such a way as to eliminate any ambient 60 Hz signals that may be present in the data. This data was stored in spreadsheet format and was analyzed to determine how the magnetic field within the Dewar was changing as a function of position

Morphology and oxygen incorporation effect on antimicrobial activity of silver thin films

Energy Technology Data Exchange (ETDEWEB)

Rebelo, Rita, E-mail: ritarebelo@det.uminho.pt [2C2T, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Manninen, N.K. [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal); Fialho, Luísa [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); Henriques, Mariana [CEB, Center for Biological Engineering, LIBRO—Laboratório de Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-335 Braga (Portugal); Carvalho, Sandra [GRF-CFUM, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); SEG-CEMUC, University of Coimbra, 3030-788 Coimbra (Portugal)

2016-05-15

Highlights: • Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering. • Coatings were characterized chemically, physically and structurally. • In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. • Ag{sub x}O coating presented antibacterial behavior. - Abstract: Ag and Ag{sub x}O thin films were deposited by non-reactive and reactive pulsed DC magnetron sputtering, respectively, with the final propose of functionalizing the SS316L substrate with antibacterial properties. The coatings were characterized chemically, physically and structurally. The coatings nanostructure was assessed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), while the coatings morphology was determined by scanning electron microscopy (SEM). The XRD and XPS analyses suggested that Ag thin film is composed by metallic Ag, which crystallizes in fcc-Ag phase, while the Ag{sub x}O thin film showed both metallic Ag and Ag−O bonds, which crystalize in fcc-Ag and silver oxide phases. The SEM results revealed that Ag thin film formed a continuous layer, while Ag{sub x}O layer was composed of islands with hundreds of nanometers surrounded by small nanoparticles with tens of nanometers. The surface wettability and surface tension parameters were determined by contact angle measurements, being found that Ag and Ag{sub x}O surfaces showed very similar behavior, with all the surfaces showing a hydrophobic character. In order to verify the antibacterial behavior of the coatings, halo inhibition zone tests were realized for Staphylococcus epidermidis and Staphylococcus aureus. Ag coatings did not show antibacterial behavior, contrarily to Ag{sub x}O coating, which presented antibacterial properties against the studied bacteria. The presence of silver oxide phase along with the development of different morphology was

The role of demagnetizing factors in the occurrence of vortex avalanches in Nb thin films

International Nuclear Information System (INIS)

Colauto, F; Ortiz, W A; Patino, E J; Aprilli, M

2009-01-01

Under specific circumstances, magnetic flux penetrates into superconducting thin films as dendritic flux jumps. The phenomenon has a thermomagnetic origin, where flux motion generates heat that suppresses flux pining and facilitates further flux motion. We have studied the thickness influence on the flux stability for very thin Nb films, 20, 40, 60, and 80 nm, through dc-magnetometry. The thicker the film; the higher is the threshold field where instabilities first take place. Due to the demagnetizing factor in a perpendicular geometry, the effective magnetic field at the border of the film is largely amplified. For thin specimens, a linear dependence between the threshold field and the thickness is expected and has been actually observed. When normalized by the sample aspect ratio, the effective threshold magnetic field is nearly the same for all specimens studied.

The role of demagnetizing factors in the occurrence of vortex avalanches in Nb thin films

Energy Technology Data Exchange (ETDEWEB)

Colauto, F; Ortiz, W A [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, C P 676, 13565-905, Sao Carlos, SP (Brazil); Patino, E J; Aprilli, M, E-mail: fcolauto@df.ufscar.b [Laboratoire de Physique des Solides, Universite Paris-Sud, C.N.R.S., 91405 Orsay cedex (France)

2009-03-01

Under specific circumstances, magnetic flux penetrates into superconducting thin films as dendritic flux jumps. The phenomenon has a thermomagnetic origin, where flux motion generates heat that suppresses flux pining and facilitates further flux motion. We have studied the thickness influence on the flux stability for very thin Nb films, 20, 40, 60, and 80 nm, through dc-magnetometry. The thicker the film; the higher is the threshold field where instabilities first take place. Due to the demagnetizing factor in a perpendicular geometry, the effective magnetic field at the border of the film is largely amplified. For thin specimens, a linear dependence between the threshold field and the thickness is expected and has been actually observed. When normalized by the sample aspect ratio, the effective threshold magnetic field is nearly the same for all specimens studied.

Microstructure and mechanical behavior of a shape memory Ni-Ti bi-layer thin film

Energy Technology Data Exchange (ETDEWEB)

Mohri, Maryam [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany); Nili-Ahmadabadi, Mahmoud, E-mail: nili@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Ivanisenko, Julia [Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany); Schwaiger, Ruth [Karlsruhe Institute of Technology, Institute for Applied Materials, 76021 Karlsruhe (Germany); Hahn, Horst; Chakravadhanula, Venkata Sai Kiran [Karlsruhe Institute of Technology, Institute of Nanotechnology, 76021 Karlsruhe (Germany)

2015-05-29

Two different single-layers and a bi-layer Ni-Ti thin films with chemical compositions of Ni{sub 45}Ti{sub 50}Cu{sub 5}, Ni{sub 50.8}Ti{sub 49.2} and Ni{sub 50.8}Ti{sub 49.2}/Ni{sub 45}Ti{sub 50}Cu{sub 5} (numbers indicate at.%) determined by energy dispersive X-ray spectroscopy were deposited on Si (111) substrates using DC magnetron sputtering. The structures, surface morphology and transformation temperatures of annealed thin films at 500 °C for 15 min and 1 h were studied using grazing incidence X-ray diffraction, transmission electron microscopy (TEM), atomic force microscopy and differential scanning calorimetry (DSC), respectively. Nanoindentation was used to characterize the mechanical properties. The DSC and X-ray diffraction results indicated the austenitic structure of the Ni{sub 50.8}Ti{sub 49.2} and martensitic structure of the Ni{sub 45}Ti{sub 50}Cu{sub 5} thin films while the bi-layer was composed of austenitic and martensitic thin films. TEM study revealed that copper encourages crystallization in the bi-layer such that crystal structure containing nano-precipitates in the Ni{sub 45}Ti{sub 50}Cu{sub 5} layer was detected after 15 min annealing while the Ni{sub 50.8}Ti{sub 49.2} layer crystallized after 60 min at 500 °C. Furthermore, after annealing at 500 °C for 15 min, a precipitate free zone and thin layer amorphous were observed closely to the interface in the top layer. The bi-layer was completely crystallized at 500 °C for 1 h and the orientation of the Ni-rich precipitates indicated a stress gradient in the bi-layer. The bi-layer thin film showed different transformation temperatures and mechanical behavior from the single-layers. The developed bi-layer has different phase transformation temperatures, the higher temperatures of shape memory effect and lower temperature of pseudo-elastic behavior compared to the single-layers. Also, the bi-layer thin film exhibited a combined pseudo-elastic behavior and shape memory effect with a reduced

Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

Science.gov (United States)

Pandey, B.; Das, D.; Kar, A. K.

2015-05-01

Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current-voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp2 content in DLC matrix. The magnetic moment vs. magnetic field (m-H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

Growth and characterization of a-axis oriented Cr-doped AlN films by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Panda, Padmalochan; Ramaseshan, R., E-mail: seshan@igcar.gov.in; Dash, S. [Materials Science Group, IGCAR, Kalpakkam, 603102 (India); Krishna, Nanda Gopala [Corrosion Science and Technology Group, IGCAR, Kalpakkam, 603102 (India)

2016-05-23

Wurtzite type Cr-doped AlN thin films were grown on Si (100) substrates using DC reactive magnetron sputtering with a function of N{sub 2} concentration (15 to 25%). Evolution of crystal structure of these films was studied by GIXRD where a-axis preferred orientation was observed. The electronic binding energy and concentration of Cr in these films were estimated by X-ray photoemission spectroscopy (XPS). We have observed indentation hardness (H{sub IT}) of around 28.2 GPa for a nitrogen concentration of 25%.

Structural, optical and electrical characterization of Ag doped lead chalcogenide (PbSe) thin films

Energy Technology Data Exchange (ETDEWEB)

Al-Ghamdi, A.A., E-mail: aghamdi90@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Heniti, S. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Khan, Shamshad A. [Department of Physics, St. Andrew' s College, Gorakhpur, UP (India)

2013-03-15

Research and development efforts are currently underway to fabricate a variety of solid state devices. A good deal of information regarding the synthesis, structural, optical and electrical properties of Ag doped lead chalcogenides have been revealed. The bulk polycrystalline (PbSe){sub 100-x}Ag{sub x} ternary chalcogenides are prepared by diffusion technique. The XRD patterns recorded for the (PbSe){sub 100-x}Ag{sub x} thin films prepared by vacuum deposition technique, show that these films are polycrystalline in nature. The optical measurements reveal that the (PbSe){sub 100-x}Ag{sub x} thin films possess direct band gap and the band gap energy decreases with an increase of Ag concentration. The extinction coefficient (k) and refractive index (n) are found to be changing by increasing Ag concentration in PbSe. These results are interpreted in terms of the change in concentration of localized states due to the shift in Fermi level. The dc conductivities of (PbSe){sub 100-x}Ag{sub x} thin films are measured in temperature range 303-403 K. It is observed that the dc conductivity increases at all the temperatures with an increase of Ag content in PbSe system. The experimental data suggests that the conduction is due to thermally assisted tunneling of the charge carriers in the localized states near the band edges. The activation energy and optical band gap are found to decrease with increasing Ag concentration in lead chalcogenide and there are good agreements between these two values. - Highlights: Black-Right-Pointing-Pointer (PbSe){sub 100-x}Ag{sub x} thin films has been investigated. Black-Right-Pointing-Pointer Polycrystalline nature has been verified by X-ray diffraction. Black-Right-Pointing-Pointer Optical absorption data showed the rules of direct transitions predominate. Black-Right-Pointing-Pointer Dc conductivity increases with an increase of Ag content in PbSe system. Black-Right-Pointing-Pointer Increase of Ag concentration causes a decrease in E{sub g

Giant spin Hall angle from topological insulator BixSe(1 - x) thin films

Science.gov (United States)

Dc, Mahendra; Jamali, Mahdi; Chen, Junyang; Hickey, Danielle; Zhang, Delin; Zhao, Zhengyang; Li, Hongshi; Quarterman, Patrick; Lv, Yang; Mkhyon, Andre; Wang, Jian-Ping

Investigation on the spin-orbit torque (SOT) from large spin-orbit coupling materials has been attracting interest because of its low power switching of the magnetization and ultra-fast driving of the domain wall motion that can be used in future spin based memory and logic devices. We investigated SOT from topological insulator BixSe(1 - x) thin film in BixSe(1 - x) /CoFeB heterostructure by using the dc planar Hall method, where BixSe(1 - x) thin films were prepared by a unique industry-compatible deposition process. The angle dependent Hall resistance was measured in the presence of a rotating external in-plane magnetic field at bipolar currents. The spin Hall angle (SHA) from this BixSe(1 - x) thin film was found to be as large as 22.41, which is the largest ever reported at room temperature (RT). The giant SHA and large spin Hall conductivity (SHC) make this BixSe(1 - x) thin film a very strong candidate as an SOT generator in SOT based memory and logic devices.

Reactive magnetron sputtering of N-doped carbon thin films on quartz glass for transmission photocathode applications

Science.gov (United States)

Balalykin, N. I.; Huran, J.; Nozdrin, M. A.; Feshchenko, A. A.; Kobzev, A. P.; Sasinková, V.; Boháček, P.; Arbet, J.

2018-03-01

N-doped carbon thin films were deposited on a silicon substrate and quartz glass by RF reactive magnetron sputtering using a carbon target and an Ar+N2 gas mixture. During the magnetron sputtering, the substrate holder temperatures was kept at 800 °C. The carbon film thickness on the silicon substrate was about 70 nm, while on the quartz glass it was in the range 15 nm – 60 nm. The elemental concentration in the films was determined by RBS and ERD. Raman spectroscopy was used to evaluate the intensity ratios I D/I G of the D and G peaks of the carbon films. The transmission photocathodes prepared were placed in the hollow-cathode assembly of a Pierce-structure DC gun to produce photoelectrons. The quantum efficiency (QE) was calculated from the laser energy and cathode charge measured. The properties of the transmission photocathodes based on semitransparent N-doped carbon thin films on quartz glass and their potential for application in DC gun technology are discussed.

Electrical resistivity of CuAlMo thin films grown at room temperature by dc magnetron sputtering

OpenAIRE

Birkett, Martin; Penlington, Roger

2016-01-01

We report on the thickness dependence of electrical resistivity of CuAlMo films grown by dc magnetron sputtering on glass substrates at room temperature. The electrical resistance of the films was monitored in situ during their growth in the thickness range 10–1000 nm. By theoretically modelling the evolution of resistivity during growth we were able to gain an insight into the dominant electrical conduction mechanisms with increasing film thickness. For thicknesses in the range 10–25 nm the ...

The Electrical Properties of Plasma-Deposited Thin Films Derived from Pelargonium graveolens

Directory of Open Access Journals (Sweden)

Ahmed Al-Jumaili

2017-10-01

Full Text Available Inherently volatile at atmospheric pressure and room temperature, plant-derived precursors present an interesting human-health-friendly precursor for the chemical vapour deposition of thin films. The electrical properties of films derived from Pelargonium graveolens (geranium were investigated in metal–insulator–metal (MIM structures. Thin polymer-like films were deposited using plasma-enhanced synthesis under various plasma input power. The J–V characteristics of thus-fabricated MIM were then studied in order to determine the direct current (DC conduction mechanism of the plasma polymer layers. It was found that the capacitance of the plasma-deposited films decreases at low frequencies (C ≈ 10−11 and remains at a relatively constant value (C ≈ 10−10 at high frequencies. These films also have a low dielectric constant across a wide range of frequencies that decreases as the input RF power increases. The conductivity was determined to be around 10−16–10−17 Ω−1 m−1, which is typical for insulating materials. The Richardson–Schottky mechanism might dominate charge transport in the higher field region for geranium thin films.

Elasticity Constants of a Two-Phase Tungsten Thin Film

Directory of Open Access Journals (Sweden)

Mohamed Fares Slim

2018-05-01

Full Text Available The IET was used to determine the macroscopic elasticity constants of the multiphase coating. In order to determine the macroscopic elasticity constants of the film firstly, a critical assessment of Young’s modulus determination was done by comparing all the models proposed in the literature. The best model was identified and a study was performed to identify and quantify the most influent factors on the global uncertainty. Secondly, an enhanced formulation to determine the shear modulus of coating by IET was developed. The methodology was applied on a tungsten thin film deposited by DC magnetron sputtering.

Etching characteristic and mechanism of BST thin films using inductively coupled Cl2/Ar plasma with additive CF4 gas

International Nuclear Information System (INIS)

Kim, Gwan-Ha; Kim, Kyoung-Tae; Kim, Dong-Pyo; Kim, Chang-Il

2004-01-01

BST thin films were etched with inductively coupled CF 4 /(Cl 2 +Ar) plasmas. The maximum etch rate of the BST thin films was 53.6 nm/min for a 10% CF 4 to the Cl 2 /Ar gas mixture at RF power of 700 W, DC bias of -150 V, and chamber pressure of 2 Pa. Small addition of CF 4 to the Cl 2 /Ar mixture increased chemical effect. Consequently, the increased chemical effect caused the increase in the etch rate of the BST thin films. To clarify the etching mechanism, the surface reaction of the BST thin films was investigated by X-ray photoelectron spectroscopy

Structural and electrical transport properties of La2Mo2O9 thin films prepared by pulsed laser deposition

Science.gov (United States)

Paul, T.; Ghosh, A.

2017-04-01

We have studied the structure and electrical properties of La2Mo2O9 thin films of different thicknesses prepared by the laser deposition technique at different substrate temperatures. The structural properties of the thin films have been investigated using XRD, XPS, AFM, TEM, SEM, and Raman spectroscopy. The electrical transport properties of the thin films have been investigated in wide temperature and frequency ranges. The cubic nature of the thin films has been confirmed from structural analysis. An enhancement of the oxygen ion conductivity of the films up to five orders of magnitude is obtained compared to that of the bulk La2Mo2O9, suggesting usefulness of the thin films as electrolytes in micro-solid oxide fuel cells. The enhanced dc ionic conductivity of the thin films has been interpreted using the rule of the mixture model, while a power law model has been used to investigate the frequency and temperature dependences of the conductivity. The analysis of the results predicts the three-dimensional oxygen ion conduction in the thin films.

RF magnetron sputtered TiNiCu shape memory alloy thin film

International Nuclear Information System (INIS)

Fu Yongqing; Du Hejun

2003-01-01

Shape memory alloys (SMAs) offer a unique combination of novel properties, such as shape memory effect, super-elasticity, biocompatibility and high damping capacity, and thin film SMAs have the potential to become a primary actuating mechanism for micro-actuators. In this study, TiNiCu films were successfully prepared by mix sputtering of a Ti 55 Ni 45 target with a separated Cu target. Crystalline structure, residual stress and phase transformation properties of the TiNiCu films were investigated using X-ray diffraction (XRD), differential scanning calorimeter (DSC), and curvature measurement methods. Effects of the processing parameters on the film composition, phase transformation and shape-memory effects were analyzed. Results showed that films prepared at a high Ar gas pressure exhibited a columnar structure, while films deposited at a low Ar gas pressure showed smooth and featureless structure. Chemical composition of TiNiCu thin films was dependent on the DC power of copper target. DSC, XRD and curvature measurement revealed clearly the martensitic transformation of the deposited TiNiCu films. When the free-standing film was heated and cooled, a 'two-way' shape-memory effect can be clearly observed

Ceramic Composite Thin Films

Science.gov (United States)

Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

2013-01-01

A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

Electronic structure and magnetic properties of Ni-doped SnO2 thin films

Science.gov (United States)

Sharma, Mayuri; Kumar, Shalendra; Alvi, P. A.

2018-05-01

This paper reports the electronic structure and magnetic properties of Ni-doped SnO2 thin film which were grown on Si (100) substrate by PLD (pulse laser deposition) technique under oxygen partial pressure (PO2). For getting electronic structure and magnetic behavior, the films were characterized using near edge X-ray absorption fine structure spectroscopy (NEXAFS) and DC magnetization measurements. The NEXAFS study at Ni L3,2 edge has been done to understand the local environment of Ni and Sn ions within SnO2 lattice. DC magnetization measurement shows that the saturation magnetization increases with the increase in substitution of Ni2+ ions in the system.

Investigation of corrosion behavior of nitrogen doped and platinum/ruthenium doped diamond-like carbon thin films in Hank's solution

Energy Technology Data Exchange (ETDEWEB)

Khun, N.W.; Liu, E., E-mail: MEJLiu@ntu.edu.sg

2011-10-10

Undoped (DLC), nitrogen-doped (N-DLC) and platinum/ruthenium doped diamond-like carbon (PtRu-DLC) thin films were deposited on p-Si (100) substrates using a DC magnetron sputtering deposition system. The chemical composition, bonding structure, surface morphology and adhesion strength of the films were characterized using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM) and micro-scratch test, respectively. The corrosion behavior of the films in a Hank's solution was investigated using potentiodynamic polarization test. The corrosion results revealed that the PtRu-DLC film had the highest corrosion potential among the films used in this study. Highlights: {yields} DLC thin films were deposited on Si substrates via dc magnetron sputtering. {yields} Some DLC films were doped with N and/or Pt/Ru. {yields} The film corrosion behavior was studied in a Hank solution with polarization test. {yields} The PtRu-DLC film showed the highest corrosion potential among the films studied.

Structural and electrical properties of sputter deposited ZnO thin films

Science.gov (United States)

Muhammed Shameem P., V.; Mekala, Laxman; Kumar, M. Senthil

2018-05-01

The growth of zinc oxide thin films having different oxygen content was achieved at ambient temperature by reactive dc magnetron sputtering technique and their structural and electrical properties are studied. The structural studies show that the films are polycrystalline with a preferential orientation of the grains along the c-axis [002], which increases with increase in oxygen partial pressure. The grain size and the surface roughness of the zinc oxide films are found to decrease with increasing oxygen partial pressure. It is observed that the resistivity of the zinc oxide films can be tuned from semiconducting to insulating regime by varying the oxygen content.

Radiofrequency amplifier based on a DC superconducting quantum interference device

International Nuclear Information System (INIS)

Martinis, J.M.; Hilbert, C.; Clarke, J.

1986-01-01

A method is described of amplifying a radiofrequency signal consisting of: disposing a single symmetrically biased dc SQUID and an input coil within a superconducting shield, the dc SQUID having a superconducting ring interrupted by two shunted Josephson junctions, and the input coil being inductively coupled solely to the ring of the single SQUID, establishing a constant magnetic flux threading the SQUID ring, applying the radiofrequency signal to the input coil from outside of the superconducting shield, obtaining an amplified radiofrequency signal solely from across the ring of the single SQUID, transmitting the amplified radiofrequency signal from across the SQUID ring to the outside of the superconducting shield

Mn-doped Ge self-assembled quantum dots via dewetting of thin films

Energy Technology Data Exchange (ETDEWEB)

Aouassa, Mansour, E-mail: mansour.aouassa@yahoo.fr [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Jadli, Imen [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Bandyopadhyay, Anup [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Kim, Sung Kyu [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Karaman, Ibrahim [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Lee, Jeong Yong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of)

2017-03-01

Highlights: • We report the new fabrication approach for producing a self- assembled Mn dpoed Ge quantum dots (QDs) on SiO{sub 2} thin film with a Curie temperature above room temperature. These magnetic QDs are crystalline, monodisperse and have a well-defined shape and a controlled size. The investigation opens new routes for elaboration of self-assembled magnetic nanocrystals - Abstract: In this study, we demonstrate an original elaboration route for producing a Mn-doped Ge self-assembled quantum dots on SiO{sub 2} thin layer for MOS structure. These magnetic quantum dots are elaborated using dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing at high temperature of an amorphous Ge:Mn (Mn: 40%) nanolayer deposed at very low temperature by high-precision Solid Source Molecular Beam Epitaxy on SiO{sub 2} thin film. The size of quantum dots is controlled with nanometer scale precision by varying the nominal thickness of amorphous film initially deposed. The magnetic properties of the quantum-dots layer have been investigated by superconducting quantum interference device (SQUID) magnetometry. Atomic force microscopy (AFM), x-ray energy dispersive spectroscopy (XEDS) and transmission electron microscopy (TEM) were used to examine the nanostructure of these materials. Obtained results indicate that GeMn QDs are crystalline, monodisperse and exhibit a ferromagnetic behavior with a Curie temperature (TC) above room temperature. They could be integrated into spintronic technology.

Electrical and magnetic properties of electrodeposited nickel incorporated diamond-like carbon thin films

Energy Technology Data Exchange (ETDEWEB)

Pandey, B., E-mail: pandey.beauty@yahoo.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Das, D. [UGC-DAE CSR, Sector III/LB-8, Bidhan Nagar, Kolkata 700098 (India); Kar, A.K. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

2015-05-15

Highlights: • Electrical and magnetic properties of DLC and Ni-DLC thin films are studied. • The ohmicity and conductivity of DLC films rise with nickel addition. • The ohmicity of Ni-DLC is enhanced with increase in dilution of electrolyte. • Dielectric loss is high for Ni-DLC and decreases with frequency till 100 kHz. • (m–H) and (m–T) curves of Ni-DLC indicate superparamagnetic behavior. - Abstract: Nanocomposite diamond-like carbon (DLC) thin films have been synthesized by incorporating nickel (Ni) nanoparticles in DLC matrix with varying concentration of nickel. DLC and Ni-DLC thin films have been deposited on ITO coated glass substrates employing low voltage electrodeposition method. Electrical properties of the samples were studied by measuring current–voltage characteristics and dielectric properties. The current approaches toward an ohmic behavior with metal addition. This tendency of increasing ohmicity is enhanced with increase in dilution of the electrolyte. The conductivity increases with Ni addition and interestingly it continues to increase with dilution of Ni concentration in the electrolyte in the range of our study. Magnetic properties for DLC and Ni-DLC thin film samples were examined by electron paramagnetic resonance (EPR) measurements and Super Conducting Quantum Interference Device (SQUID) measurements. g-Value for DLC is 2.074, whereas it decreases to 2.055 with Ni addition in the electrolyte. This decrement arises from the increased sp{sup 2} content in DLC matrix. The magnetic moment vs. magnetic field (m–H) curves of Ni-DLC indicate superparamagnetic behavior which may be due to ferromagnetic contribution from the incorporated nickel nanoparticles in the DLC matrix. The ZFC curve of Ni-DLC after the blocking temperature shows a combined contribution of ferromagnetic, superparamagnetic and paramagnetic nature of the materials persisting up to 300 K.

Studies on nonvolatile resistance memory switching in ZnO thin films

Indian Academy of Sciences (India)

Six decades of research on ZnO has recently sprouted a new branch in the domain of resistive random access memories. Highly resistive and c-axis oriented ZnO thin films were grown by us using d.c. discharge assisted pulsed laser deposition on Pt/Ti/SiO2/Si substrates at room temperature. The resistive switching ...

Optical and electrical properties of transparent conducting B-doped ZnO thin films prepared by various deposition methods

International Nuclear Information System (INIS)

Nomoto, Jun-ichi; Miyata, Toshihiro; Minami, Tadatsugu

2011-01-01

B-doped ZnO (BZO) thin films were prepared with various thicknesses up to about 500 nm on glass substrates at 200 deg. C by dc or rf magnetron sputtering deposition, pulsed laser deposition (PLD), and vacuum arc plasma evaporation (VAPE) methods. Resistivities of 4-6 x 10 -4 Ω cm were obtained in BZO thin films prepared with a B content [B/(B + Zn) atomic ratio] around 1 at. % by PLD and VAPE methods: Hall mobilities above 40 cm 2 /Vs and carrier concentrations on the order of 10 20 cm -3 . All 500-nm-thick-BZO thin films prepared with a resistivity on the order of 10 -3 -10 -4 Ω cm exhibited an averaged transmittance above 80% in the wavelength range of 400-1100 nm. The resistivity in BZO thin films prepared with a thickness below about 500 nm was found to increase over time with exposure to various high humidity environments. In heat-resistance tests, the resistivity stability of BZO thin films was found to be nearly equal to that of Ga-doped ZnO thin films, so these films were judged suitable for use as a transparent electrode for thin-film solar cells.

Host thin films incorporating nanoparticles

Science.gov (United States)

Qureshi, Uzma

The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

Investigating degradation behavior of InGaZnO thin-film transistors induced by charge-trapping effect under DC and AC gate bias stress

International Nuclear Information System (INIS)

Hsieh, Tien-Yu; Chang, Ting-Chang; Chen, Te-Chih; Tsai, Ming-Yen; Chen, Yu-Te

2013-01-01

This paper investigates the degradation mechanism of amorphous InGaZnO thin-film transistors under DC and AC gate bias stress. Comparing the degradation behavior at equal accumulated effective stress time, more pronounced threshold voltage shift under AC positive gate bias stress in comparison with DC stress indicates extra electron-trapping phenomenon that occurs in the duration of rising/falling time in pulse. Contrarily, illuminated AC negative gate bias stress exhibits much less threshold voltage shift than DC stress, suggesting that the photo-generated hole does not have sufficient time to drift to the interface of IGZO/gate insulator and causes hole-trapping under AC operation. Since the evolution of threshold voltage fits the stretched-exponential equation well, the different degradation tendencies under DC/AC stress can be attributed to the different electron- and hole-trapping efficiencies, and this is further verified by varying pulse waveform. - Highlights: ► Static and dynamic gate bias stresses are imposed on InGaZnO TFTs. ► Dynamic positive gate bias induces more pronounced threshold voltage shift. ► Static negative-bias illumination stress induces more severe threshold voltage shift. ► Evolution of threshold voltage fits the stretched-exponential equation well

Corrosion behavior of aluminum doped diamond-like carbon thin films in NaCl aqueous solution.

Science.gov (United States)

Khun, N W; Liu, E

2010-07-01

Aluminum doped diamond-like carbon (DLC:Al) thin films were deposited on n-Si(100) substrates by co-sputtering a graphite target under a fixed DC power (650 W) and an aluminum target under varying DC power (10-90 W) at room temperature. The structure, adhesion strength and surface morphology of the DLC:Al films were characterized by X-ray photoelectron spectroscopy (XPS), micro-scratch testing and atomic force microscopy (AFM), respectively. The corrosion performance of the DLC:Al films was investigated by means of potentiodynamic polarization testing in a 0.6 M NaCl aqueous solution. The results showed that the polarization resistance of the DLC:Al films increased from about 18 to 30.7 k(omega) though the corrosion potentials of the films shifted to more negative values with increased Al content in the films.

Effect of substrate type on the electrical and structural properties of TiO2 thin films deposited by reactive DC sputtering

Science.gov (United States)

Cheng, Xuemei; Gotoh, Kazuhiro; Nakagawa, Yoshihiko; Usami, Noritaka

2018-06-01

Electrical and structural properties of TiO2 thin films deposited at room temperature by reactive DC sputtering have been investigated on three different substrates: high resistivity (>1000 Ω cm) float zone Si(1 1 1), float zone Si(1 0 0) and alkali free glass. As-deposited TiO2 films on glass substrate showed extremely high resistivity of (∼5.5 × 103 Ω cm). In contrast, lower resistivities of ∼2 Ω cm and ∼5 Ω cm were obtained for films on Si(1 1 1) and Si(1 0 0), respectively. The as-deposited films were found to be oxygen-rich amorphous TiO2 for all the substrates as evidenced by X-ray photoemission spectroscopy and X-ray diffraction. Subsequent annealing led to appearance of anatase TiO2 on Si but not on glass. The surface of as-deposited TiO2 on Si was found to be rougher than that on glass. These results suggest that the big difference of electrical resistivity of TiO2 would be related with existence of more anatase nuclei forming on crystalline substrates, which is consistent with the theory of charged clusters that smaller clusters tend to adopt the substrate structure.

Characterization of CuS nanocrystalline thin films synthesized by chemical bath deposition and dip coating techniques

International Nuclear Information System (INIS)

Chaki, Sunil H.; Deshpande, M.P.; Tailor, Jiten P.

2014-01-01

CuS thin films were synthesized by chemical bath deposition and dip coating techniques at ambient temperature. The energy dispersive analysis of X-rays of the thin films confirmed that both the as synthesized thin films are stoichiometric. The X-ray diffraction of the chemical bath deposited and dip coating deposited thin films showed that the films possess hexagonal structure having lattice parameters, a = b = 3.79 A and c = 16.34 A. The crystallite sizes determined from the X-ray diffraction data using Scherrer's formula for the chemical bath deposition and dip coating deposition thin films came out to be nearly 11 nm and 13 nm, respectively. The optical microscopy of the as deposited thin films surfaces showed that the substrates are well covered in both the deposited films. The scanning electron microscopy of the thin films clearly showed that in chemical bath deposited thin films the grain size varies from few μm to nm, while in dip coating deposited films the grain size ranges in nm. The optical bandgap determined from the optical absorbance spectrum analysis showed, chemical bath deposited thin films possess direct bandgap of 2.2 eV and indirect bandgap of 1.8 eV. In the case of dip coating deposited thin films, the direct bandgap is 2.5 eV and indirect bandgap is 1.9 eV. The d.c. electrical resistivity variation with temperature for both the deposited films showed that the resistivity decreases with temperature thus confirming the semiconducting nature. The thermoelectric power variations with temperature and the room temperature Hall Effect study of both the synthesized CuS thin films showed them to be of p-type conductivity. The obtained results are discussed in details. - Highlights: • CuS thin films were synthesized by chemical bath deposition and dip coating techniques. • The films possessed hexagonal structure. • The optical absorption showed that the films had direct and indirect bandgap. • Study of electrical transport properties

Photocatalytic Activity of Nanostructured Titanium Dioxide Thin Films

Directory of Open Access Journals (Sweden)

Zdenek Michalcik

2012-01-01

Full Text Available The aim of this paper is to investigate the properties and photocatalytic activity of nanostructured TiO2 layers. The glancing angle deposition method with DC sputtering at low temperature was applied for deposition of the layers with various columnar structures. The thin-film structure and surface morphology were analyzed by XRD, SEM, and AFM analyses. The photocatalytic activity of the films was determined by the rate constant of the decomposition of the Acid Orange 7. In dependence on the glancing angle deposition parameters, three types of columnar structures were obtained. The films feature anatase/rutile and/or amorphous structures depending on the film architecture and deposition method. All the films give the evidence of the photocatalytic activity, even those without proved anatase or rutile structure presence. The impact of columnar boundary in perspective of the photocatalytic activity of nanostructured TiO2 layers was discussed as the possible factor supporting the photocatalytic activity.

Imaging, manipulation and flux noise of single Abrikosov vortices in YBa2Cu3O7-δ dc SQUIDs

International Nuclear Information System (INIS)

Bailer, Matthias

2013-01-01

The thesis deals with the imaging and investigation of single Abrikosov vortices in grain boundary dc SQUIDs1 from the high-temperature superconductor YBa 2 Cu 3 O 7-δ . The low temperature scanning electron microscopy (LTSEM) was used for the measurements, which makes a local, spatially resolved investigation of the electrical properties of materials at low temperatures possible. The advantage over other flux quantum imaging methods is the facility to determine the low-frequency flux noise in the SQUID in the process. Special SQUID designs were created, which allow a reproducible cooling of single flux quanta. Electrical transport and noise measurements were carried out to precharacterise the SQUIDs. Within the scope of the thesis it was the first time that antivortices were imaged with the LTSEM. The possibilities of a manipulation of flux quanta (with the electron beam) were investigated and illustrated. By the averaged measurement of the waveform of a single vortex, linescans with unprecedented resolution could be obtained. This allowed the outstanding comparison of the measured, virtual vortex displacement with various theoretically determined waveforms. The experiments to flux noise provided new insights into the noise behaviour of single flux quanta, which exhibit the typical single fluctuators random telegraph signal, and enabled the analysis of the associated hopping processes. Thus concrete values of the spectral noise power density S r ∼ 196 nm 2 /root(Hz) - 0,28 μm 2 /root(Hz) radially to the SQUID hole could be determined by different, pinned vortices. An influence of the hopping behaviour and therefore of the flux noise succeeded by varying an applied magnetic field. Through tilting the potential course of a vortex, the course of the pinning potential by different hopping processes could be reconstructed using stochastic analysis of the time trace data. With the thesis could be shown convincingly that the vortex imaging method of the LTSEM in

NMR characterization of thin films

Science.gov (United States)

Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2010-06-15

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

NMR characterization of thin films

Science.gov (United States)

Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2008-11-25

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

Effect of sputtering parameters and substrate composition on the structure of tantalum thin films

Energy Technology Data Exchange (ETDEWEB)

Hallmann, Lubica, E-mail: lubica.hallmann@zzm.uzh.c [Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zürich (Switzerland); Ulmer, Peter [Institute of Geochemistry and Petrology, ETH Zürich (Switzerland)

2013-10-01

The crystallographic properties of tantalum films deposited as a bioactive coating on Co–Cr–Mo and Ti–Al–Nb alloys have been investigated. The desired tough and ductile alpha phase of tantalum has been obtained by DC magnetron sputtering on Co–Cr–Mo and Ti–Al–Nb substrates. The thickness of the tantalum layer was between 20 and 600 nm. The crystallographic structure of tantalum thin film was dependent on the sputtering parameters such as DC power, bias voltage and gas impurities. Oxygen is an important factor for the stabilization of the tantalum alpha phase on Co–Cr–Mo substrate. The crystallographic structure and texture of tantalum thin films was found to be additionally dependent on the substrate composition. For Ti–Al–Nb substrate, oxygen content was not an important factor for the stabilization of the alpha phase. The observed shift of X-ray diffraction peaks to lower 2(θ) is an indication of stress evolving during the sputtering process and was dependent on bias voltage and oxygen content of the carrier gas.

Handbook of thin film technology

CERN Document Server

Frey, Hartmut

2015-01-01

“Handbook of Thin Film Technology” covers all aspects of coatings preparation, characterization and applications. Different deposition techniques based on vacuum and plasma processes are presented. Methods of surface and thin film analysis including coating thickness, structural, optical, electrical, mechanical and magnetic properties of films are detailed described. The several applications of thin coatings and a special chapter focusing on nanoparticle-based films can be found in this handbook. A complete reference for students and professionals interested in the science and technology of thin films.

Construction of sputtering system and preparation of high temperature superconducting thin films

International Nuclear Information System (INIS)

Kaynak, E.

2000-01-01

The preparation of high T c superconducting thin film is important both for the understanding of fundamental behaviours of these materials and for the investigations on the usefulness of technological applications. High quality thin films can be prepared by various kinds of techniques being used today. Among these, sputtering is the most preferred one. The primary aim of this work is the construction of a r. f. and c. magnetron sputtering system. For this goal, a magnetron sputtering system was designed and constructed having powers up to 500W (r.f.) and 1KW (d.c.) that enables to deposit thin films of various kinds of materials: metals, ceramics and magnetic materials. The temperature dependence of the electrical resistance of the films was investigated by using four-point probe method. The zero resistance and the transition with of the films were measured as 80-85 K, and 2-9 K, respectively. The A.C. susceptibility experiments were done by utilising the system that was designed and constructed. The applied field dependence of the real and imaginary components of the susceptibility that were measured between the 77-120 K temperature interval and at a fixed frequency was investigated

Rare Earth Oxide Thin Films

CERN Document Server

Fanciulli, Marco

2007-01-01

Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

Thin-film solar cells

International Nuclear Information System (INIS)

Aberle, Armin G.

2009-01-01

The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

Facing-target sputtering deposition of ZnO films with Pt ultra-thin layers for gas-phase photocatalytic application

International Nuclear Information System (INIS)

Zhang Zhonghai; Hossain, Md. Faruk.; Arakawa, Takuya; Takahashi, Takakazu

2010-01-01

In this paper, various zinc oxide (ZnO) films are deposited by a versatile and effective dc-reactive facing-target sputtering method. The ratios of Ar to O 2 in the mixture gas are varied from 8:2 to 6:4 at a fixed sputtering pressure of 1.0 Pa. X-ray diffraction, spectrophotometer and scanning electron microscope are used to study the crystal structure, optical property and surface morphology of the as-deposited films. The Pt ultra-thin layer, ∼2 nm thick, is deposited on the surface of ZnO film by dc diode sputtering with a mesh mask controlling the coated area. The photocatalytic activity of ZnO films and Pt-ZnO films is evaluated by decomposition of methanol under UV-vis light irradiation. The variation of photocatalytic activity depends on the ratios of Ar to O 2 , which is mainly attributed to the different grain size and carrier mobility. Though the pure ZnO film normally shows a low gas-phase photocatalytic activity, its activity is significantly enhanced by depositing Pt ultra-thin layer.

Process for forming thin film, heat treatment process of thin film sheet, and heat treatment apparatus therefor

International Nuclear Information System (INIS)

Watanabe, S.

1984-01-01

The invention provides a process for forming a magnetic thin film on a base film, a heat treatment process of a thin film sheet consisting of the base film and the magnetic thin film, and an apparatus for performing heat treatment of the thin film sheet. Tension applied to the thin film sheet is substantially equal to that applied to the base film when the magnetic thin film is formed thereon. Then, the thin film sheet is treated with heat. The thin film sheet is heated with a given temperature gradient to a reactive temperature at which heat shrinkage occurs, while the tension is being applied thereto. Thereafter, the thin film sheet to which the tension is still applied is cooled with substantially the same temperature gradient as applied in heating. The heat treatment apparatus has a film driving unit including a supply reel, a take-up reel, a drive source and guide rollers; a heating unit including heating plates, heater blocks and a temperature controller for heating the sheet to the reactive temperature; and a heat insulating unit including a thermostat and another temperature controller for maintaining the sheet at the nonreactive temperature which is slightly lower than the reactive temperature

A Humidity-Dependent Lifetime Derating Factor for DC Film Capacitors

DEFF Research Database (Denmark)

Wang, Huai; Reigosa, Paula Diaz; Blaabjerg, Frede

2015-01-01

accelerated testing of film capacitors under different humidity conditions, enabling a more justified lifetime prediction of film capacitors for DC-link applications under specific climatic environments. The analysis of the testing results and the detailed discussion on the derating factor with different......Film capacitors are widely assumed to have superior reliability performance than Aluminum electrolytic capacitors in DC-link design of power electronic converters. However, the assumption needs to be critically judged especially for applications under high humidity environments. This paper proposes...... a humidity-dependent lifetime derating factor for a type of plastic-boxed metallized DC film capacitors. It overcomes the limitation that the humidity impact is not considered in the state-of-the-art DC film capacitor lifetime models. The lifetime derating factor is obtained based on a total of 8,700 hours...

Application of a substrate bias to control the droplet density on Cu(In,Ga)Se{sub 2} thin films grown by Pulsed Electron Deposition

Energy Technology Data Exchange (ETDEWEB)

Rampino, S. [IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma (Italy); Pattini, F., E-mail: rampino@imem.cnr.it [IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma (Italy); Malagù, C.; Pozzetti, L. [Department of Physics and Earth Sciences, University of Ferrara, Via Saragat, 1-44122 Ferrara (Italy); Stefancich, M. [LENS Laboratory, Masdar Institute of Science and Technology, Masdar City, PO Box 54224, Abu Dhabi (United Arab Emirates); Bronzoni, M. [IMEM-CNR Institute, Parco Area delle Scienze 37/A, 43124 Parma (Italy)

2014-07-01

One of the main shortcomings in the fabrication of thin-film solar cells by pulsed high-energy deposition techniques (i.e. Pulsed Laser Deposition or Pulsed Electron Deposition — PED), is the presence of a significant number of particulates on the film surface. This affects the morphological properties of the cell active layers and, ultimately, the performance of the final device. To reduce the density of these defects, we deposited a Cu(In,Ga)Se{sub 2} (CIGS) thin film by PED and studied the effect on the film morphology when a DC bias was applied between the substrate and the target. Our results show that a negative substrate voltage, comprised between 0 and − 300 V, can not only reduce the droplet density on the CIGS film surface of about one order of magnitude with respect to the standard unbiased case (from 6 × 10{sup 5} to 5 × 10{sup 4} cm{sup −2}), but also lower the maximum particulate size and the surface smoothness. When a positive voltage is applied, we observed that a significant increase in the droplet surface density (up to 10{sup 8} cm{sup −2}) occurs. The abrupt change in the preferred crystal orientation (switching from (112) to (220)/(204) by applying negative and positive biases, respectively) is also a direct consequence of the applied DC voltage. These results confirm that the external DC bias could be used as an additional parameter to control the physical properties of thin films grown by PED. - Highlights: • Cu(In,Ga)Se{sub 2} (CIGS) films were grown by Pulsed Electron Deposition (PED). • Positive and negative DC biases were applied between the target and the substrate. • The droplet density can be reduced by one order of magnitude by DC negative bias. • Chemical composition and grain orientation of CIGS are influenced by the DC bias. • The DC bias can be an additional parameter of PED for controlling the film properties.

Growth and characterization of textured YBaCo{sub 2}O{sub 5+δ} thin films grown on (001)-SrTiO{sub 3} via DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Galeano, V. [Universidad Nacional de Colombia, Campus Medellín, Facultad de Ciencias, Departamento de Física, Laboratorio de Cerámicos y Vítreos, A.A. 568, Medellín (Colombia); Arnache, O. [Grupo de Estado Sólido, Departamento de Física, Universidad de Antioquia, A.A. 1226, Medellín (Colombia); Supelano, I.; Vargas, C.A. Parra [Universidad Pedagógica y Tecnológica de Colombia, Departamento de Física, Avenida Central del Norte 39-115, Tunja (Colombia); Morán, O., E-mail: omoranc@unal.edu.co [Universidad Nacional de Colombia, Campus Medellín, Facultad de Ciencias, Departamento de Física, Laboratorio de Cerámicos y Vítreos, A.A. 568, Medellín (Colombia)

2016-06-30

Thin films of the layered cobaltite YBaCo{sub 2}O{sub 5+δ} were successfully grown on (001)-oriented SrTiO{sub 3} single-crystal substrates by means of DC magnetron sputtering. The 112 phase of the compound was stabilized by choosing an adequate Co reactant and through careful thermal treatment of the target. The results demonstrate the strong influence of these variables on the final phase of the compound. A substrate temperature of 1053 K and an oxygen pressure of 300 Pa seemed to be appropriate growing conditions for depositing (00ℓ)-textured YBaCo{sub 2}O{sub 5+δ} thin films onto the chosen substrate. In like fashion to the polycrystalline YBaCo{sub 2}O{sub 5+δ}, the films showed a clear sequence of antiferromagnetic–ferromagnetic–paramagnetic transitions within a narrow temperature range. Well-defined hysteresis loops were observed at temperatures as high as 270 K, which supports the existence of a FM order in the films. In turn, the dependence of the resistivity on the temperature shows a semiconductor-like behavior, without any distinguishable structure, within the temperature range measured (50–350 K). The analysis of the experimental data showed that the transport mechanism in the films is well described by using the Mott variable range hopping (VRH) conduction model. - Highlights: • YBaCo{sub 2}O{sub 5+δ} thin films are grown on SrTiO{sub 3} substrates. • Strong (00ℓ) reflections are observed in the X-ray diffraction pattern. • A clear sequence of magnetic transitions is observed. • Semiconducting-like behavior is verified.

Properties of high temperature SQUIDS

International Nuclear Information System (INIS)

Falco, C.M.; Wu, C.T.

1978-01-01

A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb 3 Sn is outlined, and comments are made on directions future work should take

Metal-insulator transition in tin doped indium oxide (ITO thin films: Quantum correction to the electrical conductivity

Directory of Open Access Journals (Sweden)

Deepak Kumar Kaushik

2017-01-01

Full Text Available Tin doped indium oxide (ITO thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes in low temperatures (25-300 K. The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l is the electron mean free path and degenerate semiconductors. The transport of charge carriers (electrons in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known ‘metal-insulator transition’ (MIT which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC; this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann’s expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

Science.gov (United States)

Kaushik, Deepak Kumar; Kumar, K. Uday; Subrahmanyam, A.

2017-01-01

Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl˜1; kF is the Fermi wave vector and l is the electron mean free path) and degenerate semiconductors. The transport of charge carriers (electrons) in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known `metal-insulator transition' (MIT) which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC); this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann's expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

International Nuclear Information System (INIS)

Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

1992-01-01

Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

B{sub 4}C thin films for neutron detection

Energy Technology Data Exchange (ETDEWEB)

Hoeglund, Carina [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linkoeping University, SE-581 83 Linkoeping (Sweden); Birch, Jens; Jensen, Jens; Hultman, Lars [Department of Physics, Chemistry and Biology (IFM), Thin Film Physics Division, Linkoeping University, SE-581 83 Linkoeping (Sweden); Andersen, Ken; Hall-Wilton, Richard [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Bigault, Thierry; Buffet, Jean-Claude; Correa, Jonathan; Esch, Patrick van; Guerard, Bruno; Piscitelli, Francesco [Institute Laue Langevin, Rue Jules Horowitz, FR-380 00 Grenoble (France); Khaplanov, Anton [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); Institute Laue Langevin, Rue Jules Horowitz, FR-380 00 Grenoble (France); Vettier, Christian [European Spallation Source ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden); European Synchrotron Radiation Facility, BP 220, FR-380 43 Grenoble Cedex 9 (France); Vollenberg, Wilhelmus [Vacuum, Surfaces and Coatings Group (TE/VSC), CERN, CH-1211 Geneva 23 (Switzerland)

2012-05-15

Due to the very limited availability of {sup 3}He, new kinds of neutron detectors, not based on {sup 3}He, are urgently needed. Here, we present a method to produce thin films of {sup 10}B{sub 4}C, with maximized detection efficiency, intended to be part of a new generation of large area neutron detectors. B{sub 4}C thin films have been deposited onto Al-blade and Si wafer substrates by dc magnetron sputtering from {sup nat}B{sub 4}C and {sup 10}B{sub 4}C targets in an Ar discharge, using an industrial deposition system. The films were characterized with scanning electron microscopy, elastic recoil detection analysis, x-ray reflectivity, and neutron radiography. We show that the film-substrate adhesion and film purity are improved by increased substrate temperature and deposition rate. A deposition rate of 3.8 A/s and substrate temperature of 400 deg. C result in films with a density close to bulk values and good adhesion to film thickness above 3 {mu}m. Boron-10 contents of almost 80 at. % are obtained in 6.3 m{sup 2} of 1 {mu}m thick {sup 10}B{sub 4}C thin films coated on Al-blades. Initial neutron absorption measurements agree with Monte Carlo simulations and show that the layer thickness, number of layers, neutron wavelength, and amount of impurities are determining factors. The study also shows the importance of having uniform layer thicknesses over large areas, which for a full-scale detector could be in total {approx}1000 m{sup 2} of two-side coated Al-blades with {approx}1 {mu}m thick {sup 10}B{sub 4}C films.

Growth and Characteristic of Amorphous Nano-Granular TeO2-V2O5-NiO Thin Films

Science.gov (United States)

Hosseinzadeh, Sh.; Rahmati, A.; Bidadi, H.

2016-12-01

TeO2-V2O5-NiO thin films were deposited using thermal evaporation from 40TeO2-(60-y)V2O5-yNiO (y=0-30mol%) target. Structural analysis of the films was identified by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The amorphous TeO2-V2O5-NiO films have nanosized clear grain structure and sharp grain boundaries. DC conductivity and current-voltage (I-V) characteristic of TeO2-V2O5-NiO thin films were measured in the temperature range of 300-423K. As nickel oxide (NiO) content increases, the DC conductivity decreases up to two orders in value (10-9-10-11Sṡcm-1). Temperature dependence of conductivity is described using the small polaron hopping (SPH) model as well. Poole-Frenkel effect is observed at high external electric field. The optical absorption spectra of the TeO2-V2O5-NiO thin films were recorded in the wavelength range of 380-1100nm. The absorption coefficient revealed bandgap shrinkage (3.01-2.3eV) and band tail widening, due to an increase in NiO content. Energy dispersive X-ray spectroscopy (EDX) was used to determine elemental composition. In TeO2-V2O5-NiO thin films, the NiO content is around fifth of the initial target.

Control of the magnetic properties of LaMnO3 epitaxial thin films grown by Pulsed Laser Deposition

Science.gov (United States)

Martinez, Benjamin; Roqueta, Jaume; Pomar, Alberto; Balcells, Lluis; Frontera, Carlos; Konstantinovic, Zorica; Sandiumenge, Felip; Santiso, Jose; Advanced materials characterization Team; Thin films growth Team

2015-03-01

LaMnO3 (LMO), the parent compound of colossal magnetoresistance based manganites has gained renewed attention as a building block in heterostructures with unexpected properties. In its bulk phase, stoichiometric LMO is an A-type antiferromagnetic (AFM) insulator (TN = 140K) with orthorhombic structure that easily accommodate an oxygen excess by generating cationic (La or Mn) vacancies. As a result, a fraction of Mn 3+ changes to Mn 4+ leading to a double-exchange mediated ferromagnetic (FM) behavior. In thin films the AFM phase has been elusive up to now and thin films with FM ordering are usually reported. In this work, we have systematically studied the growth process of LaMnO3 thin films by pulsed laser deposition on SrTiO3 (001) substrates under different oxygen partial pressures (PO2) . A close correlation between the structure (explored by XRD) and the magnetic properties (SQUID measurements) of the films with PO2 has been identified. At high PO2 FM behavior is observed. In contrast, at very low PO2, the results obtained for unit cell volume (close to stoichiometric bulk values) and magnetic moment (0.2 μB/Mn) strongly indicate antiferromagnetic ordering. We acknowledge financial support from the Spanish MINECO (MAT2012-33207).

Effect of oxygen partial pressure on the structural and optical properties of dc sputtered ITO thin films

International Nuclear Information System (INIS)

Kerkache, L.; Layadi, A.; Mosser, A.

2009-01-01

We present results on the effect of the partial pressure of oxygen (ppo) on the structural and optical properties of tin-doped indium oxide, In 2 O 3 :Sn (ITO), thin films deposited on glass substrates by reactive dc diode sputtering. The deposition rate decreases with increasing ppo. The ppo did not affect the chemical composition of the ITO films as inferred from X-ray photoemission spectroscopy (XPS). From X-ray diffraction, we find out that the samples have crystalline structure in the ppo range 2 x 10 -4 to 6 x 10 -4 mbar and are amorphous outside this range. These samples have a preferred orientation for ppo between 2 x 10 -4 and 4.5 x 10 -4 mbar, but as the ppo increased beyond 4.7 x 10 -4 mbar, the texture dominates. This change occurs for the same substrate temperature (about 130 deg. C). The grain size decreases as the ppo increases. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) have been used to investigate the surface roughness and the morphology of these samples. The optical transmission is greater than 90% in the visible region and does depend on the ppo. The refractive index n values are found to be in the 1.68-1.86 range. The energy gap values are between 3.1 and 3.5 eV.

Characterization of chemically deposited Ag/sub 2/S thin films

International Nuclear Information System (INIS)

Choudhury, M.G.M.; Rahman, M.M; Shahjahan, M.; Hossain, M.S.; Muhibbullah, M.; Uddin, M.A.; Banu, D.A.

2001-01-01

Silver Sulphide (Ag/sub 2/S) thin films were prepared by the chemical deposition method on glass substrates. Films of different thickness were deposited at room temperature. The films obtained were found to the uniform, pin-hole free and strongly adherent to the substrates. Films were characterized by X-$D, Hall effect, dc conductivity, thermoelectric power and optical measurements. X-RD revealed that as deposited films are amorphous with some microcrystalline structure. Hall effect measurement shows that the material deposited is n-type semiconductor with carrier concentration of the order of 10/sup 14/ cm/sup -3/. The dc dark conductivity shows two distinct conduction regions. The conductivity increases quite sharply above a transition temperature. Tt and below Tt the conductivity is weakly activated process with hopping via localized states. Above Tt the activation energy is quite high and the conduction may be due to impurity states to extended states. From the nature of variation of thermoelectric power with temperature it was found that in this material the position of Fermi level lie above the conduction band for thicker films and below the conduction band for relatively thinner films. The optical band gap of the films has been calculated from the transmittance spectra. The evaluated optical band gap E/sup opt/ was found to be about 1.1 eV and the value do not change much with film thickness. The refractive index, extinction coefficient and dielectric constants have also been evaluated from the transmission measurements. (author)

Optical and electrical properties of transparent conducting B-doped ZnO thin films prepared by various deposition methods

Energy Technology Data Exchange (ETDEWEB)

Nomoto, Jun-ichi; Miyata, Toshihiro; Minami, Tadatsugu [Optoelectronic Device System R and D Center, Kanazawa Institute of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921-8501 (Japan)

2011-07-15

B-doped ZnO (BZO) thin films were prepared with various thicknesses up to about 500 nm on glass substrates at 200 deg. C by dc or rf magnetron sputtering deposition, pulsed laser deposition (PLD), and vacuum arc plasma evaporation (VAPE) methods. Resistivities of 4-6 x 10{sup -4}{Omega} cm were obtained in BZO thin films prepared with a B content [B/(B + Zn) atomic ratio] around 1 at. % by PLD and VAPE methods: Hall mobilities above 40 cm{sup 2}/Vs and carrier concentrations on the order of 10{sup 20} cm{sup -3}. All 500-nm-thick-BZO thin films prepared with a resistivity on the order of 10{sup -3}-10{sup -4}{Omega} cm exhibited an averaged transmittance above 80% in the wavelength range of 400-1100 nm. The resistivity in BZO thin films prepared with a thickness below about 500 nm was found to increase over time with exposure to various high humidity environments. In heat-resistance tests, the resistivity stability of BZO thin films was found to be nearly equal to that of Ga-doped ZnO thin films, so these films were judged suitable for use as a transparent electrode for thin-film solar cells.

Effect of thickness on electrical properties of SILAR deposited SnS thin films

Science.gov (United States)

Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba

2016-03-01

Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.

Development of non-destructive evaluation system using an HTS-SQUID gradiometer for magnetized materials

Science.gov (United States)

Kawano, J.; Tsukamoto, A.; Adachi, S.; Oshikubo, Y.; Hato, T.; Tanabe, K.; Okamura, T.

We have developed a new eddy-current non-destructive evaluation (NDE) system using an HTS SQUID gradiometer with the aim of applying it to practical materials with magnetization. The new NDE system employs a LN2-cooled external Cu pickup coil and an HTS SQUID chip placed in a magnetic shield made of HTS material. The HTS SQUID chip consists of an HTS planar gradiometer manufactured by using a ramp-edge junction technology and a multi-turn HTS thin film input coil coupled with the flip-chip configuration. The first-order coaxial gradiometric Cu pickup coil with a diameter of 16 mm and the baseline of 5.6 mm was used in the present NDE experiments. By using this NDE system, we could observe defect-induced magnetic signals without an appreciable influence of magnetization up to 10 mT. We also examined the ability of detecting deep-lying defects and compared with the results obtained using our previous NDE system.

Characterization of phase change Ga{sub 15}Se{sub 77}Ag{sub 8} chalcogenide thin films by laser-irradiation

Energy Technology Data Exchange (ETDEWEB)

Alvi, M.A., E-mail: alveema@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Zulfequar, M. [Department of Physics, Jamia Millia Islamia, New Delhi 110025 (India); Al-Ghamdi, A.A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2013-02-15

Highlights: Black-Right-Pointing-Pointer Effect of laser-irradiation on structure and optical band gap has been investigated. Black-Right-Pointing-Pointer The amorphous nature has been verified by X-ray diffraction and DSC measurements. Black-Right-Pointing-Pointer Laser-irradiation causes a decrease in optical band gap in Ga{sub 15}Se{sub 77}Ag{sub 8} thin films. Black-Right-Pointing-Pointer The decrease in optical band gap can be interpreted on the basis of amorphous-crystalline phase transformation. Black-Right-Pointing-Pointer Optical absorption data showed that the rules of the non-direct transitions predominate. - Abstract: Phase change Ga{sub 15}Se{sub 77}Ag{sub 8} chalcogenide thin films were prepared by thermal evaporation technique. Thin films were then irradiated by Transverse Electrical Excitation at Atmospheric Pressure (TEA) nitrogen laser for different time intervals. The X-ray structural characterization revealed the amorphous nature of as-prepared films while the laser irradiated films show the polycrystalline nature. Field Emission Scanning Electron Microscope (FESEM) has been used to study the structural changes. The results are discussed in terms of the structural aspects and amorphous to crystalline phase change in Ga{sub 15}Se{sub 77}Ag{sub 8} chalcogenide thin films. The observed changes are associated with the interaction of the incident photon and the lone-pairs electrons which affects the band gap of the Ga{sub 15}Se{sub 77}Ag{sub 8} chalcogenide thin films. The optical constants of these thin films are measured by using the absorption spectra measurements as a function of photon energy in the wavelength region 400-1100 nm. It is found that the optical band gap decreases while the absorption coefficient and extinction coefficient increases with increasing the laser-irradiation time. The decrease in the optical band gap has been explained on the basis of change in nature of films, from amorphous to polycrystalline state. The dc

Ultrahigh vacuum dc magnetron sputter-deposition of epitaxial Pd(111)/Al2O3(0001) thin films.

Science.gov (United States)

Aleman, Angel; Li, Chao; Zaid, Hicham; Kindlund, Hanna; Fankhauser, Joshua; Prikhodko, Sergey V; Goorsky, Mark S; Kodambaka, Suneel

2018-05-01

Pd(111) thin films, ∼245 nm thick, are deposited on Al 2 O 3 (0001) substrates at ≈0.5 T m , where T m is the Pd melting point, by ultrahigh vacuum dc magnetron sputtering of Pd target in pure Ar discharges. Auger electron spectra and low-energy electron diffraction patterns acquired in situ from the as-deposited samples reveal that the surfaces are compositionally pure 111-oriented Pd. Double-axis x-ray diffraction (XRD) ω-2θ scans show only the set of Pd 111 peaks from the film. In triple-axis high-resolution XRD, the full width at half maximum intensity Γ ω of the Pd 111 ω-rocking curve is 630 arc sec. XRD 111 pole figure obtained from the sample revealed six peaks 60°-apart at a tilt angles corresponding to Pd 111 reflections. XRD ϕ scans show six 60°-rotated 111 peaks of Pd at the same ϕ angles for 11[Formula: see text]3 of Al 2 O 3 based on which the epitaxial crystallographic relationships between the film and the substrate are determined as [Formula: see text]ǁ[Formula: see text] with two in-plane orientations of [Formula: see text]ǁ[Formula: see text] and [Formula: see text]ǁ[Formula: see text]. Using triple axis symmetric and asymmetric reciprocal space maps, interplanar spacings of out-of-plane (111) and in-plane (11[Formula: see text]) are found to be 0.2242 ± 0.0003 and 0.1591 ± 0.0003 nm, respectively. These values are 0.18% lower than 0.2246 nm for (111) and the same, within the measurement uncertainties, as 0.1588 nm for (11[Formula: see text]) calculated from the bulk Pd lattice parameter, suggesting a small out-of-plane compressive strain and an in-plane tensile strain related to the thermal strain upon cooling the sample from the deposition temperature to room temperature. High-resolution cross-sectional transmission electron microscopy coupled with energy dispersive x-ray spectra obtained from the Pd(111)/Al 2 O 3 (0001) samples indicate that the Pd-Al 2 O 3 interfaces are essentially atomically abrupt and

Controlled formation of anatase and rutile TiO₂ thin films by reactive magnetron sputtering

OpenAIRE

Rafieian, Damon; Ogieglo, Wojciech; Savenije, T.J.; Lammertink, Rob G H

2015-01-01

We discuss the formation of TiO2 thin films via DC reactive magnetron sputtering. The oxygen concentration during sputtering proved to be a crucial parameter with respect to the final film structure and properties. The initial deposition provided amorphous films that crystallise upon annealing to anatase or rutile, depending on the initial sputtering conditions. Substoichiometric films (TiOx), obtained by sputtering at relatively low oxygen concentration, formed rutile upon annealing in air, ...

Optoelectronic properties of R-F magnetron sputtered Cadmium Tin Oxide (Cd2SnO4) thin films for CdS/CdTe thin film solar cell applications

International Nuclear Information System (INIS)

Jeyadheepan, K.; Thamilselvan, M.; Kim, Kyunghae; Yi, Junsin; Sanjeeviraja, C.

2015-01-01

Highlights: • Characterization of “as-prepared” Cd 2 SnO 4 thin films ideal for thin film solar cells. • Lowest value of resistivity with high mobility attained for the as-prepared Cd 2 SnO 4 films. • Maximum transmittance of 93% in the visible range for the as-prepared films. • Effect of substrate temperature on the scattering mechanism of TCO. - Abstract: The influence of substrate temperature on the microstructural behavior, optical, electrical properties and on the scattering mechanism of charge carriers were studied for the as-prepared radio-frequency (R-F) magnetron sputtered Cadmium Tin Oxide (Cd 2 SnO 4 ) thin films. Films prepared at the substrate temperature of 300 °C were found to be polycrystalline in nature with preferential orientation along (3 1 1) plane. Well pronounced Moss–Burstein shift, in the transmittance spectra with dispersions in the optical band gap from 3.07 to 3.30 eV, was observed at substrate temperatures between 25 and 300 °C. Optical property of high visible transmittance was retained by the films. Analysis of the electrical properties on the prepared crystalline Cd 2 SnO 4 films showed a calculated resistivity of 10 −3 –10 −4 Ω cm, with n-type carrier density in the range of 10 19 –10 20 cm −3 and the charge carrier mobility in the range of 63–30 cm 2 /V s. The effects of structural, compositional and optical properties on the scattering mechanism of charge carrier are elaborated and reported to be an experimental evidence for the theoretical predictions. The results revealed the essential DC electrical conduction behavior, which is ideal for the fabrication of Cd 2 SnO 4 -based CdS/CdTe thin film solar cells

Thin film metal-oxides

CERN Document Server

Ramanathan, Shriram

2009-01-01

Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

Thin films and nanomaterials

International Nuclear Information System (INIS)

Jayakumar, S.; Kannan, M.D.; Prasanna, S.

2012-01-01

The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

Superconducting thin films of YBa2Cu3O7-x

International Nuclear Information System (INIS)

Hudner, J.

1993-01-01

Thin films of the high temperature superconductor YBa 2 Cu 3 O 7-x (YBCO) are of significance in fundamental studies of oxide superconductors and for prospected electronic applications based on superconductors operating at liquid nitrogen temperatures (T= 77 K). Synthesis of YBCO thin films is complex and a large part of this thesis has been devoted to the elaboration of various techniques in forming YBCO thin films. A general observation was that synthesis of YBCO films exhibiting high zero-resistivity temperatures temperatures (T c ) ≥ 88 K and elevated critical current densities (J c ) ≥ 10 6 A/cm 2 at 77 K was possible under widely different conditions of film growth. For the BaF 2 -based method, various substrate materials were investigated. Among perovskite related substrates with low losses in the high frequency regime, LaA10 3 was found to yield YBCO films exhibiting the highest quality electrical properties. A study of YBCO film interaction with sapphire substrates was performed. It was suggested that the YBCO film on sapphire consists of weakly coupled superconducting grains. Compositional effects of Y, BA and Cu for MOCVD-YBCO films were examined with respect to morphology, structure, resistivity, as susceptibility and J c (T). High T c :s and J c :s were observed for an anomalous large compositional range of Cu in off-compositional YBCO films. This was shown to be related to the formation of Cu-rich precipitates embedded within a c-Axis oriented stoichiometric YBCO film matrix. Thermal critical current behavior at zero field in thin films of YBCO fabricated by various methods has been studied by three techniques: transport measurements on patterned microbridges, dc magnetization hysteresis loops using the Bean model and non-linear ac susceptibility analysis. Absolute critical current values obtained form the two former techniques when measured on the same YBCO film were observed to differ about a factor of two. The feasibility of non-linear ac

A FED Prototype Using Patterned DLC Thin Films as the Cathode

Science.gov (United States)

Li, W.; Feng, T.; Mao, D. S.; Wang, X.; Liu, X. H.; Zou, S. C.; Zhu, Y. K.; Li, Q.; Xu, J. F.; Jin, S.; Zheng, J. S.

In our study, diamond-like-carbon (DLC) thin films were prepared by filtered arc deposition (FAD), which provided a way to deposit DLC thin films on large areas at room temperature. Glass slides coated 100nm chromium or titanium thin films were used as cathode substrates. Millions of rectangular holes with sizes of 5 × 5μm were made on the DLC films using a routine patterning process. Here a special reactive ion beam etching method was applied to etch the DLC films. The anodes of the devices were made by electrophoretic deposition. ZnO:Zn phosphor (P15) was employed, which has a broad band bluish green (centered at 490nm). Before electrophoretic deposition, the anode substrates (ITO glass slides) had been patterned into 50 anode electrodes. In order to improve the adherence of phosphor layers, the as-deposited screens were treated in Na2SiO3 solution for 24h to add additional binder. A kind of matrix-addressed diode FED prototype was designed and packaged. 50-100μm-thick glass slides were used as spacers and getters were applied to maintain the vacuum after the exhaustion. The applied DC voltage was ranged in 0-3000V and much higher current density was measured in the cathode-patterned prototypes than the unpatterned ones during the test. As a result, characters could be well displayed.

Nb nanoSQUIDs for detection of small spin systems

Energy Technology Data Exchange (ETDEWEB)

Woelbing, R.; Nagel, J.; Kemmler, M.; Kleiner, R.; Koelle, D. [Physikalisches Institut, Universitaet Tuebingen (Germany); Kieler, O.; Weimann, T.; Kohlmann, J.; Zorin, A. [Fachbereich 2.4 ' ' Quantenelektronik' ' , PTB Braunschweig (Germany); Buchter, A.; Xue, F.; Poggio, M. [Department of Physics, University of Basel (Switzerland); Rueffer, D.; Russo-Averchi, E.; Fontcuberta i Morral, A. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Huber, R.; Berberich, P. [Physik-Department E10, Technische Universitaet Muenchen (Germany); Grundler, D. [Laboratoire des Materiaux Semiconducteurs, EPF Lausanne (Switzerland); Physik-Department E10, Technische Universitaet Muenchen (Germany)

2013-07-01

We report on the realization of highly sensitive dc nanoSQUIDs for the investigation of small spin systems in moderate magnetic fields. The Nb SQUIDs are based on normal metal Josephson junctions made of HfTi and patterned by e-beam lithography. We demonstrate stable operation up to B = ± 50 mT without degradation of rms flux noise (S{sub Φ}{sup 1/2} ≤ 280 nΦ{sub 0}/√(Hz)). We also present a multifunctional system combining a Nb nanoSQUID and a low-temperature magnetic force microscope (LTMFM) with a Ni nanotube as a scanning tip. This system allows for magnetization measurements of the Ni tube by using both, LTMFM and SQUID readout. Furthermore, the measurement of magnetic flux Φ vs. position of the particle provides an experimental determination of the coupling factor φ{sub μ} = Φ/μ between SQUID and Ni tube with magnetic moment μ. The results confirm our predictions from numerical simulations, taking into account the SQUID geometry.

X-ray photoelectron spectroscopy study and thermoelectric properties of Al-doped ZnO thin films

International Nuclear Information System (INIS)

Li Li; Fang Liang; Zhou Xianju; Liu Ziyi; Zhao Liang; Jiang Sha

2009-01-01

In this paper, high quality Al-doped ZnO (AZO) thin films were prepared by direct current (DC) reactive magnetron sputtering using a Zn target (99.99%) containing Al of 1.5 wt.%. The films obtained were characterized by X-ray photoelectron spectroscopy (XPS) and thermoelectric measurements. The XPS results reveal that Zn and Al exist only in oxidized state, while there are dominant crystal lattice and rare adsorbed oxygen for O in the annealed AZO thin films. The studies of thermoelectric property show a striking thermoelectric effect in the AZO thin films. On the one hand, the thermoelectromotive and magnetothermoelectromotive forces increase linearly with increasing temperature difference (ΔT). On the other hand, the thermoelectric power (TEP) decreases with the electrical resistance of the sample. But the TEP increases with the increase of temperature below 300 K, and it nearly does not change around room temperature. The experimental results also demonstrate that the annealing treatment increases TEP, while the external magnetic field degrades TEP.

Multiferroicity in oxide thin films and heterostructures

International Nuclear Information System (INIS)

Glavic, Artur

2012-01-01

In this work a variety of different systems of transition metal oxides ABO 3 (perovskite materials, where B stands for a transition metal and A for a rare earth element) were produced as thin films and heterostructures and analyzed for the structural, magnetic and ferroelectric properties. For the epitaxial film preparation mostly pulse laser deposition (PLD) was applied. For one series high pressure oxide sputter deposition was used as well. The bulk multiferroics TbMnO 3 and DyMnO 3 , which develop their electric polarization due to a cycloidal magnetic order, have been prepared as single layers with thicknesses between 2 and 200 nm on YAlO 3 substrates using PLD and sputter deposition. The structural characterization of the surfaces and crystal structure where performed using X-ray reflectometry and diffraction, respectively. These yielded low surface roughness and good epitaxial growth. The magnetic behavior was macroscopically measured with SQUID magnetometry and microscopically with polarized neutron diffraction and resonant magnetic X-ray scattering. While all investigated samples showed antiferromagnetic order, comparable with the collinear magnetic phase of their bulk materials, only the sputter deposited samples exhibited the multiferroic low temperature cycloidal order. The investigation of the optical second harmonic generation in a TbMnO 3 sample could proof the presence of a ferroelectric order in the low temperature phase. The respective transition temperatures of the thin films have been very similar to those of the bulk materials. In contrast an increase in the rare earth ordering temperature has been observed, which reduces the Mn order slightly, an effect not known from bulk TbMnO 3 crystals. The coupling of the antiferromagnetic order in TbMnO 3 to ferromagnetic layers of LaCoO 3 was investigated in super-lattices containing 20 bilayers produced with PLD on the same substrates. The SQUID magnetometry yielded a strong influence of the

Nb3Al thin film deposition for low-noise terahertz electronics

International Nuclear Information System (INIS)

Dochev, D; Pavolotsky, A B; Belitsky, V; Olofsson, H

2008-01-01

Higher energy gap superconducting materials were always interesting for low-noise mixer applications such as superconductor-insulator-superconductor tunnel junctions (SIS) and hot-electron bolometer (HEB) used in sub-millimeter and terahertz parts of electro-magnetic spectrum. Here, we report a novel approach for producing Nb 3 Al thin film by co-sputtering from two confocally arranged Nb and Al dc-magnetrons onto substrate heated up to 830 deg. C. Characterization of the deposited films revealed presence of the A15 phase and measured critical temperature was up to 15.7 K with the transition width 0.2-0.3 K for a 300 nm thick film. We measured the film critical magnetic field and studied influence of annealing on the film properties. We have investigated compositional depth profile of the deposited films by spectroscopy of reflected electrons

Wet-Chemical Surface Texturing of Sputter-Deposited ZnO:Al Films as Front Electrode for Thin-Film Silicon Solar Cells

Directory of Open Access Journals (Sweden)

Xia Yan

2015-01-01

Full Text Available Transparent conductive oxides (TCOs play a major role as the front electrodes of thin-film silicon (Si solar cells, as they can provide optical scattering and hence improved photon absorption inside the devices. In this paper we report on the surface texturing of aluminium-doped zinc oxide (ZnO:Al or AZO films for improved light trapping in thin-film Si solar cells. The AZO films are deposited onto soda-lime glass sheets via pulsed DC magnetron sputtering. Several promising AZO texturing methods are investigated using diluted hydrochloric (HCl and hydrofluoric acid (HF, through a two-step etching process. The developed texturing procedure combines the advantages of the HCl-induced craters and the smaller and jagged—but laterally more uniform—features created by HF etching. In the two-step process, the second etching step further enhances the optical haze, while simultaneously improving the uniformity of the texture features created by the HCl etch. The resulting AZO films show large haze values of above 40%, good scattering into large angles, and a surface angle distribution that is centred at around 30°, which is known from the literature to provide efficient light trapping for thin-film Si solar cells.

SQUIDs for the readout of metallic magnetic calorimeters

Energy Technology Data Exchange (ETDEWEB)

Ferring, Anna; Wegner, Mathias; Fleischmann, Andreas; Gastaldo, Loredana; Kempf, Sebastian; Enss, Christian [Kirchhoff-Institute for Physics, Heidelberg University (Germany)

2015-07-01

Superconducting quantum interference devices (SQUIDs) are the devices of choice to read out metallic magnetic calorimeters (MMCs). Here, the temperature change of the detector upon the absorption of an energetic particle is measured as a magnetization change of a paramagnetic temperature sensor that is situated in a weak magnetic field. Driven by the need for devices that allow for the readout of large-scale detector arrays with hundreds or even thousands of individual detectors as well as of single channel detectors with sub-eV energy resolution, we have recently started the development of low-T{sub c} current-sensing SQUIDs. In particular, we are developing cryogenic frequency-domain multiplexers based on non-hysteretic rf-SQUIDs for detector array readout as well as dc-SQUIDs for single channel detector readout. We discuss our SQUID designs and the performance of prototype SQUIDs. We particularly focus on the frequency and temperature dependence of the SQUID noise as well as the reliability of our SQUID fabrication process for Nb/Al-AlO{sub x}/Nb Josephson junctions. Additionally, we demonstrate experimentally that state-of-the-art MMCs can successfully be read out with our current devices. Finally, we discuss different strategies to improve the SQUID and detector performance aiming to reach sub-eV energy resolution for individual detectors as well as for detector arrays.

Preparation of p-type transparent conducting tin-antimony oxide thin films by DC reactive magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Ji, Zhenguo [College of Electronic Information, Hangzhou Dianzi University, Hangzhou (China); State Key Laboratory for Silicon Materials, Zhejiang University, Hangzhou (China); Xi, Junhua; Huo, Lijuan; Zhao, Yi [State Key Laboratory for Silicon Materials, Zhejiang University, Hangzhou (China)

2008-07-01

P-type transparent conducting tin-antimony oxide (TAO) films were successfully prepared by DC reactive magnetron sputtering followed by post annealing in the air. Structural, optical and electrical properties of the TAO films were investigated. X-ray diffraction studies showed that the films are polycrystalline with orthorhombic structure of Sb{sub 2}O{sub 4}. UV-Visible absorption and transmittance spectra showed that the optical band-gap of the TAO films is about 3.90 eV, and the overall transmittance is higher than 85% in the visible region. Hall effect measurement indicated that the Sn/Sb ratio is a critical parameter to get p-type conducting TAO films. It was found that 0.19films could be obtained. Hole concentration as high as 4.03 x 10{sup 19} cm{sup -3} and electrical resistivity as low as 0.155 {omega}cm were achieved, showing potential applications of TAO films as p-type transparent conducting films. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Optical and electrical properties of TiOPc doped Alq{sub 3} thin films

Energy Technology Data Exchange (ETDEWEB)

Ramar, M.; Suman, C. K., E-mail: sumanck@nplindia.org; Tyagi, Priyanka; Srivastava, R. [CSIR-Network of Institutes for Solar Energy CSIR - National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi -110012 (India)

2015-06-24

The Titanyl phthalocyanine (TiOPc) was doped in Tris (8-hydroxyquinolinato) aluminum (Alq3) with different concentration. The thin film of optimized doping concentration was studied extensively for optical and electrical properties. The optical properties, studied using ellipsometry, absorption and photoluminescence. The absorption peak of Alq{sub 3} and TiOPc was observed at 387 nm and 707 nm and the photo-luminescence intensity (PL) peak of doped thin film was observed at 517 nm. The DC and AC electrical properties of the thin film were studied by current density-voltage (J-V) characteristics and impedance over a frequency range of 100 Hz - 1 MHz. The electron mobility calculated from trap-free space-charge limited region (SCLC) is 0.17×10{sup −5} cm{sup 2}/Vs. The Cole-Cole plots shows that the TiOPc doped Alq{sub 3} thin film can be represented by a single parallel resistance R{sub P} and capacitance C{sub P} network with a series resistance R{sub S} (10 Ω). The value of R{sub P} and C{sub P} at zero bias was 1587 Ω and 2.568 nF respectively. The resistance R{sub P} decreases with applied bias whereas the capacitance C{sub P} remains almost constant.

Thin film device applications

CERN Document Server

Kaur, Inderjeet

1983-01-01

Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

Preparation and characterization of photocatalytic performance of hierarchical heterogeneous nanostructured ZnO/TiO2 films made by DC magnetron sputtering

International Nuclear Information System (INIS)

Le Phuc Quy; Vu Thi Hanh Thu

2013-01-01

With the aim to enhance photocatalytic properties and anti-Ecoli bacteria abilities of TiO 2 thin films; hierarchical heterogeneous nanostructured ZnO/TiO 2 (HN s ) films were deposited by DC magnetron sputtering. The obtained results showed that both the photocatalytic performance and anti-Ecoli bacteria ability of HN s films exhibited enhancement in comparison with standard TiO 2 films. This enhancement was explained due to the reduction of the electron - hole recombination and the red shift of absorption edge of the HNs films. (author)

Effect of Oxygen Partial Pressure on the Electrical and Optical Properties of DC Magnetron Sputtered Amorphous TiO2 Films

OpenAIRE

Chandra Sekhar, M.; Kondaiah, P.; Radha Krishna, B.; Uthanna, S.

2013-01-01

Titanium dioxide (TiO2) thin films were deposited on p-Si (100) and Corning glass substrates held at room temperature by DC magnetron sputtering at different oxygen partial pressures in the range 9 × 10−3–9 × 10−2 Pa. The influence of oxygen partial pressure on the structural, electrical, and optical properties of the deposited films was systematically studied. XPS studies confirmed that the film formed at an oxygen partial pressure of 6×10−2 Pa was nearly stoichiometric. TiO2 films formed at...

Biomimetic thin film synthesis

Energy Technology Data Exchange (ETDEWEB)

Graff, G.L.; Campbell, A.A.; Gordon, N.R.

1995-05-01

The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

A SQUID gradiometer module with wire-wound pickup antenna and integrated voltage feedback circuit

Energy Technology Data Exchange (ETDEWEB)

Zhang Guofeng [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Yi, E-mail: y.zhang@fz-juelich.de [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Zhang Shulin [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS), Shanghai 200050 (China); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); Krause, Hans-Joachim [Peter Gruenberg Institute (PGI-8), Forschungszentrum Juelich (FZJ), D-52425 Juelich (Germany); Joint Research Laboratory on Superconductivity and Bioelectronics, Collaboration between CAS-Shanghai and FZJ, Shanghai 200050 (China); and others

2012-10-15

The performance of the direct readout schemes for dc SQUID, Additional Positive Feedback (APF), noise cancellation (NC) and SQUID bootstrap circuit (SBC), have been studied in conjunction with planar SQUID magnetometers. In this paper, we examine the NC technique applied to a niobium SQUID gradiometer module with an Nb wire-wound antenna connecting to a dual-loop SQUID chip with an integrated voltage feedback circuit for suppression of the preamplifier noise contribution. The sensitivity of the SQUID gradiometer module is measured to be about 1 fT/(cm {radical}Hz) in the white noise range in a magnetically shielded room. Using such gradiometer, both MCG and MEG signals are recorded.

Effects of DC gate and drain bias stresses on the degradation of excimer laser crystallized polysilicon thin film transistors

International Nuclear Information System (INIS)

Kouvatsos, D N; Michalas, L; Voutsas, A T; Papaioannou, G J

2005-01-01

The effects of gate and drain bias stresses on thin film transistors fabricated in polysilicon films crystallized using the advanced sequential lateral solidification excimer laser annealing (SLS ELA) process, which yields very elongated polysilicon grains and allows the fabrication of TFTs without grain boundary barriers to current flow, are investigated as a function of the active layer thickness and of the TFT orientation relative to the grains. The application of hot carrier stress, with a condition of V GS = V DS /2, was determined to induce threshold voltage, subthreshold swing and transconductance degradation for TFTs in thicker polysilicon films and the associated stress-induced increase in the active layer trap density was evaluated. However, this device degradation was drastically reduced for TFTs fabricated in ultra-thin films. Furthermore, the application of the same stress condition to TFTs oriented vertically to the elongated grains resulted in similar threshold voltage shift but in substantially decreased subthreshold swing and transconductance degradation. The immunity of ultra-thin active layer devices to degradation under hot carrier stress clearly suggests the implementation of ultra thin SLS ELA polysilicon films for the fabrication of TFTs exhibiting not only high performance but, especially, the high reliability needed for integrated systems on panel

Deposition of PZT thin film onto copper-coated polymer films by mean of pulsed-DC and RF-reactive sputtering

Czech Academy of Sciences Publication Activity Database

Suchaneck, G.; Labitzke, R.; Adolphi, B.; Jastrabík, Lubomír; Adámek, Petr; Drahokoupil, Jan; Hubička, Zdeněk; Kiselev, D.A.; Kholkin, A. L.; Gerlach, G.; Dejneka, Alexandr

2011-01-01

Roč. 205, č. 2 (2011), S241-S244 ISSN 0257-8972 R&D Projects: GA ČR GC202/09/J017; GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : pulsed DC reactive sputtering * RF reactive sputtering * complex oxide film deposition * polymer substrate Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.867, year: 2011

Thin Film Photovoltaic Partnership Project | Photovoltaic Research | NREL

Science.gov (United States)

Thin Film Photovoltaic Partnership Project Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the United States from 1994 to 2009. The project made many advances in thin-film PV technologies that allowed

Thin Film & Deposition Systems (Windows)

Data.gov (United States)

Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

Low-temperature deposition of ZnO thin films on PET and glass substrates by DC-sputtering technique

International Nuclear Information System (INIS)

Banerjee, A.N.; Ghosh, C.K.; Chattopadhyay, K.K.; Minoura, Hideki; Sarkar, Ajay K.; Akiba, Atsuya; Kamiya, Atsushi; Endo, Tamio

2006-01-01

The structural, optical and electrical properties of ZnO thin films (260 - 490 nm thick) deposited by direct-current sputtering technique, at a relatively low-substrate temperature (363 K), onto polyethylene terephthalate and glass substrates have been investigated. X-ray diffraction patterns confirm the proper phase formation of the material. Optical transmittance data show high transparency (80% to more than 98%) of the films in the visible portion of solar radiation. Slight variation in the transparency of the films is observed with a variation in the deposition time. Electrical characterizations show the room-temperature conductivity of the films deposited onto polyethylene terephthalate substrates for 4 and 5 h around 0.05 and 0.25 S cm -1 , respectively. On the other hand, for the films deposited on glass substrates, these values are 8.5 and 9.6 S cm -1 for similar variation in the deposition time. Room-temperature conductivity of the ZnO films deposited on glass substrates is at least two orders of magnitude higher than that of ZnO films deposited onto polyethylene terephthalate substrates under identical conditions. Hall-measurements show the maximum carrier concentration of the films on PET and glass substrate around 2.8 x 10 16 and 3.1 x 10 2 cm -3 , respectively. This report will provide newer applications of ZnO thin films in flexible display technology

High speed non-latching squid binary ripple counter

International Nuclear Information System (INIS)

Silver, A.H.; Phillips, R.R.; Sandell, R.D.

1985-01-01

High speed, single flux quantum (SFQ) binary scalers are important components in superconducting analog-to-digital converters (ADC). This paper reviews the concept for a SQUID ADC and the design of an SFQ binary ripple counter, and reports the simulation of key components, and fabrication and performance of non-latching SQUID scalers and SFQ binary ripple counters. The SQUIDs were fabricated with Nb/Nb 2 O 5 /PbIn junctions and interconnected by monolithic superconducting transmission lines and isolation resistors. Each SQUID functioned as a bistable flip-flop with the input connected to the center of the device and the output across one junction. All junctions were critically damped to optimize the pulse response. Operation was verified by observing the dc I-V curves of successive SQUIDs driven by a cw pulse train generated on the same chip. Each SQUID exhibited constant-voltage current steps at 1/2 the voltage of the preceding device as expected from the Josephson voltage-to-frequency relation. Steps were observed only for the same voltage polarity of successive devices and for proper phase bias of the SQUID. Binary frequency division was recorded up to 40GHz for devices designed to operate to 28GHz

Characterization of organic thin films

CERN Document Server

Ulman, Abraham; Evans, Charles A

2009-01-01

Thin films based upon organic materials are at the heart of much of the revolution in modern technology, from advanced electronics, to optics to sensors to biomedical engineering. This volume in the Materials Characterization series introduces the major common types of analysis used in characterizing of thin films and the various appropriate characterization technologies for each. Materials such as Langmuir-Blodgett films and self-assembled monolayers are first introduced, followed by analysis of surface properties and the various characterization technologies used for such. Readers will find detailed information on: -Various spectroscopic approaches to characterization of organic thin films, including infrared spectroscopy and Raman spectroscopy -X-Ray diffraction techniques, High Resolution EELS studies, and X-Ray Photoelectron Spectroscopy -Concise Summaries of major characterization technologies for organic thin films, including Auger Electron Spectroscopy, Dynamic Secondary Ion Mass Spectrometry, and Tra...

Structure and magnetization of Co4N thin film

Science.gov (United States)

Pandey, Nidhi; Gupta, Mukul; Gupta, Rachana; Rajput, Parasmani; Stahn, Jochen

2018-02-01

In this work, we studied the local structure and the magnetization of Co4N thin films deposited by a reactive dc magnetron sputtering process. The interstitial incorporation of N atoms in a fcc Co lattice is expected to expand the structure. This expansion yields interesting magnetic properties e.g. a larger magnetic moment (than Co) and a very high value of spin polarization ratio in Co4N . By optimizing the growth conditions, we prepared Co4N film having lattice parameter close to its theoretically predicted value. The N concentration was measured using secondary ion mass spectroscopy. Detailed magnetization measurements using bulk magnetization method and polarized neutron reflectivity confirm that the magnetic moment of Co in Co4N is higher than that of Co.

Electrochromism in surface modified crystalline WO3 thin films grown by reactive DC magnetron sputtering

Science.gov (United States)

Karuppasamy, A.

2013-10-01

In the present work, tungsten oxide thin films were deposited at various oxygen chamber pressures (1.0-5.0 × 10-3 mbar) by maintaining the sputtering power density and argon pressure constant at 3.0 W/cm2 and 1.2 × 10-2 mbar, respectively. The role of surface morphology and porosity on the electrochromic properties of crystalline tungsten oxide thin films has been investigated. XRD and Raman studies reveal that all the samples post annealed at 450 ̊C in air for 3.0 h settle in monoclinic crystal system of tungsten oxide (W18O49). Though the phase of material is indifferent to oxygen pressure variations (PO2), morphology and film density shows a striking dependence on PO2. A systematic study on plasma (OES), morphology, optical and electrochromic properties of crystalline tungsten oxide reveal that the films deposited at PO2 of 2.0 × 10-3 mbar exhibit better coloration efficiency (58 cm2/C), electron/ion capacity (Qc: -25 mC/cm2), and reversibility (92%). This is attributed to the enhanced surface properties like high density of pores and fine particulates (100 nm) and to lesser bulk density of the film (ρ/ρo = 0.84) which facilitates the process of intercalation/de-intercalation of protons and electrons. These results show good promise toward stable and efficient crystalline tungsten oxide based electrochromic device applications.

Josephson soliton oscillators in a superconducting thin film resonator

DEFF Research Database (Denmark)

Holm, J.; Mygind, Jesper; Pedersen, Niels Falsig

1993-01-01

Josephson soliton oscillators integrated in a resonator consisting of two closely spaced coplanar superconducting microstrips have been investigated experimentally. Pairs of long 1-D Josephson junctions with a current density of about 1000 A/cm2 were made using the Nb-AlOx-Nb trilayer technique....... Different modes of half-wave resonances in the thin-film structure impose different magnetic field configurations at the boundaries of the junctions. The DC I-V characteristic shows zero-field steps with a number of resonator-induced steps. These structures are compared to RF-induced steps generated...

Nb{sub 3}Al thin film deposition for low-noise terahertz electronics

Energy Technology Data Exchange (ETDEWEB)

Dochev, D; Pavolotsky, A B; Belitsky, V; Olofsson, H [Group for Advanced Receiver Development and Onsala Space Observatory, Department of Radio- and Space Science, Chalmers University of Technology, SE 412 96 Gothenburg (Sweden)], E-mail: dimitar.dochev@chalmers.se

2008-02-01

Higher energy gap superconducting materials were always interesting for low-noise mixer applications such as superconductor-insulator-superconductor tunnel junctions (SIS) and hot-electron bolometer (HEB) used in sub-millimeter and terahertz parts of electro-magnetic spectrum. Here, we report a novel approach for producing Nb{sub 3}Al thin film by co-sputtering from two confocally arranged Nb and Al dc-magnetrons onto substrate heated up to 830 deg. C. Characterization of the deposited films revealed presence of the A15 phase and measured critical temperature was up to 15.7 K with the transition width 0.2-0.3 K for a 300 nm thick film. We measured the film critical magnetic field and studied influence of annealing on the film properties. We have investigated compositional depth profile of the deposited films by spectroscopy of reflected electrons.

Controlling thin film structure for the dewetting of catalyst nanoparticle arrays for subsequent carbon nanofiber growth

International Nuclear Information System (INIS)

Randolph, S J; Fowlkes, J D; Melechko, A V; Klein, K L; III, H M Meyer; Simpson, M L; Rack, P D

2007-01-01

Vertically aligned carbon nanofiber (CNF) growth is a catalytic chemical vapor deposition process in which structure and functionality is controlled by the plasma conditions and the properties of the catalyst nanoparticles that template the fiber growth. We have found that the resultant catalyst nanoparticle network that forms by the dewetting of a continuous catalyst thin film is dependent on the initial properties of the thin film. Here we report the ability to tailor the crystallographic texture and composition of the nickel catalyst film and subsequently the nanoparticle template by varying the rf magnetron sputter deposition conditions. After sputtering the Ni catalyst thin films, the films are heated and exposed to an ammonia dc plasma, to chemically reduce the native oxide on the films and induce dewetting of the film to form nanoparticles. Subsequent nanoparticle treatment in an acetylene plasma at high substrate temperature results in CNF growth. Evidence is presented that the texture and composition of the nickel thin film has a significant impact on the structure and composition of the formed nanoparticle, as well as the resultant CNF morphology. Nickel films with a preferred (111) or (100) texture were produced and conditions favoring interfacial silicidation reactions were identified and investigated. Both compositional and structural analysis of the films and nanoparticles indicate that the properties of the as-deposited Ni catalyst film influences the subsequent nanoparticle formation and ultimately the catalytic growth of the carbon nanofibers

Pure and Nb2O5-doped TiO2 amorphous thin films grown by dc magnetron sputtering at room temperature: Surface and photo-induced hydrophilic conversion studies

International Nuclear Information System (INIS)

Suchea, M.; Christoulakis, S.; Tudose, I.V.; Vernardou, D.; Lygeraki, M.I.; Anastasiadis, S.H.; Kitsopoulos, T.; Kiriakidis, G.

2007-01-01

Photo-induced hydrophilicity of titanium dioxide makes this material one of the most suitable for various coating applications in antifogging mirrors and self-cleaning glasses. The field of functional titanium dioxide coatings is expanding rapidly not only in applications for glass but also in applications for polymer, metal and ceramic materials. The high hydrophilic surface of TiO 2 is interesting for understanding also the basic photon-related surface science of titanium dioxide. In doing so, it is inevitably necessary to understand the relationship between the photoreaction and the surface properties. In this work, photo-induced hydrophilic conversion was evaluated on amorphous pure and niobium oxide-doped titanium dioxide thin films on Corning 1737F glass grown by dc magnetron sputtering technique at room temperature. This study is focused on the influence of the Ar:O ratio during sputtering plasma deposition on thin film surface morphology and subsequent photo-induced hydrophilic conversion results. Structural characterization carried out by X-ray diffraction and atomic force microscopy (AFM) has shown that our films are amorphous and extremely smooth with a surface roughness bellow 1 nm. Contact angle measurements were performed on as-deposited and during/after 10 min UV exposure. We present evidence that the photo-induced hydrophilic conversion of film surface is directly correlated with surface morphology and can be controlled by growth conditions

OPTICAL PROPERTIES OF Al:ZnO THIN FILM DEPOSITED BY DIFFERENT SOL-GEL TECHNIQUES: ULTRASONIC SPRAY PYROLYSIS AND DIP-COATING

Directory of Open Access Journals (Sweden)

Ebru Gungor

2016-08-01

Full Text Available Undoped and Al-doped ZnO polycrystalline thin films have been fabricated on glass substrates by using a computer-controlled dip coating (DC and ultrasonic spray pyrolysis (USP systems. The film deposition parameters of DC process were optimized for the samples. In this technique, the substrate was exposed to temperature gradient using a tube furnace. In the study, the other solvent-based technique was conventional USP. The zinc salt and Al salt concentrations in the solution were kept constant as 0.1 M and 2% of Zn salt’s molarity, respectively. The optical properties were compared for the films deposited two different techniques. The optical transmission of Al:ZnO/Glass/Al:ZnO sample dip coated and  the optical transmission of Al:ZnO/Glass sample ultrasonically sprayed were determined higher than 80% in the visible and near infrared region. Experimental optical transmittance spectra of the films in the forms of FilmA/Glass/FilmA and FilmA/glass were used to determine the optical constants. It was observed that the optical band gaps of Al doped ZnO films onto glass substrate were increases with increase of Al content and the absorption edge shifted to the shorter wavelength (blue shift compared with the undoped ZnO thin film.

Self-Limited Growth in Pentacene Thin Films.

Science.gov (United States)

Pachmajer, Stefan; Jones, Andrew O F; Truger, Magdalena; Röthel, Christian; Salzmann, Ingo; Werzer, Oliver; Resel, Roland

2017-04-05

Pentacene is one of the most studied organic semiconducting materials. While many aspects of the film formation have already been identified in very thin films, this study provides new insight into the transition from the metastable thin-film phase to bulk phase polymorphs. This study focuses on the growth behavior of pentacene within thin films as a function of film thickness ranging from 20 to 300 nm. By employing various X-ray diffraction methods, combined with supporting atomic force microscopy investigations, one crystalline orientation for the thin-film phase is observed, while three differently tilted bulk phase orientations are found. First, bulk phase crystallites grow with their 00L planes parallel to the substrate surface; second, however, crystallites tilted by 0.75° with respect to the substrate are found, which clearly dominate the former in ratio; third, a different bulk phase polymorph with crystallites tilted by 21° is found. The transition from the thin-film phase to the bulk phase is rationalized by the nucleation of the latter at crystal facets of the thin-film-phase crystallites. This leads to a self-limiting growth of the thin-film phase and explains the thickness-dependent phase behavior observed in pentacene thin films, showing that a large amount of material is present in the bulk phase much earlier during the film growth than previously thought.

Fine control of the amount of preferential <001> orientation in DC magnetron sputtered nanocrystalline TiO2 films

International Nuclear Information System (INIS)

Stefanov, B; Granqvist, C G; Österlund, L

2014-01-01

Different crystal facets of anatase TiO 2 are known to have different chemical reactivity; in particular the {001} facets which truncates the bi-tetrahedral anatase morphology are reported to be more reactive than the usually dominant {101} facets. Anatase TiO 2 thin films were deposited by reactive DC magnetron sputtering in Ar/O 2 atmosphere and were characterized using Rietveld refined grazing incidence X-ray diffraction, atomic force microscopy and UV/Vis spectroscopy. By varying the partial O2 pressure in the deposition chamber, the degree of orientation of the grains in the film could be systematically varied with preferred <001> orientation changing from random upto 39% as determined by March-Dollase method. The orientation of the films is shown to correlate with their reactivity, as measured by photo-degradation of methylene blue in water solutions. The results have implications for fabrication of purposefully chemically reactive thin TiO 2 films prepared by sputtering methods

Me-Si-C (Me= Nb, Ti or Zr) : Nanocomposite and Amorphous Thin Films

OpenAIRE

Tengstrand, Olof

2012-01-01

This thesis investigates thin films of the transition metal carbide systems Ti-Si-C, Nb-Si-C, and Zr-Si-C, deposited at a low substrate temperature (350 °C) with dc magnetron sputtering in an Ar discharge. Both the electrical and mechanical properties of these systems are highly affected by their structure. For Nb-Si-C, both the ternary Nb-Si-C and the binary Nb-C are studied. I show pure NbC films to consist of crystalline NbC grains embedded in a matrix of amorphous carbon. The best combina...

Effect of thickness on surface morphology, optical and humidity sensing properties of RF magnetron sputtered CCTO thin films

Energy Technology Data Exchange (ETDEWEB)

Ahmadipour, Mohsen [Structural Materials Niche Area, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Ain, Mohd Fadzil [School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Ahmad, Zainal Arifin, E-mail: srzainal@usm.my [Structural Materials Niche Area, School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

2016-11-01

Highlights: • CCTO thin film was synthesized by RF magnetron sputtering successfully. • Increase in thickness lead to increase in grain size and decrease in band gap. • Short response times and recovery times of lead CCTO humidity sensor. • Sensor could detect humidity range (30–90%). - Abstract: In this study, calcium copper titanate (CCTO) thin films were deposited on ITO substrates successfully by radio frequency (RF) magnetron sputtering method in argon atmosphere. The CCTO thin films present a polycrystalline, uniform and porous structure. The surface morphology, optical and humidity sensing properties of the synthesized CCTO thin films have been studied by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), UV–vis spectrophotometer and current-voltage (I–V) analysis. XRD and AFM confirmed that the intensity of peaks and pore size of CCTO thin films were enhanced by increasing the thin films. Tauc plot method was adopted to estimate the optical band gaps. The surface structure and energy band gaps of the deposited films were affected by film thickness. Energy band gap of the layers were 3.76 eV, 3.68 eV and 3.5 eV for 200 nm, 400 nm, and 600 nm CCTO thin films layer, respectively. The humidity sensing properties were measured by using direct current (DC) analysis method. The response times were 12 s, 22 s, and 35 s while the recovery times were 500 s, 600 s, and 650 s for 200 nm, 400 nm, and 600 nm CCTO thin films, respectively at humidity range of 30–90% relative humidity (RH).

High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

Energy Technology Data Exchange (ETDEWEB)

Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2015-02-14

We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

Plan for SQUID microscope at ASRC: Vision, purposes and the present status

International Nuclear Information System (INIS)

Kadowaki, K.; Kakeya, I.; Suzuki, J.; Hata, Y.; Hojyo, K

2001-01-01

A new research plan to develop SQUID microscope and apply it to advanced science and technology research was started in the year of 2000 at the Advanced Science Research Center (ASRC) of JAERI (Japan Atomic Energy Research Institute). This plan was made to develop 'research of ultrafine magnetic structures with magnetic microscope' and is scheduled to continue five years. Principle of SQUID magnetic microscope is to observe changes of magnetic field in microscopic space using SQUID element as the magnetic probe. At present this type of instrument is fabricated by Seiko Instruments Inc. in Japan and is commercially available. Therefore, this plan is being promoted in collaboration with Seiko Instruments Inc. One of the main issues of the present plan is to raise the spatial resolution to the extremity. As of magnetic microscopes, 'magnetic force microscope' and 'scanning Hall probe microscope' also exist. They have different characteristics of their own. The present plan needs challenging technical developments in various fields. Supposed the spatial resolution be made very high, for example, by making very fine SQUID loop with ultrafine processing, critical technologies like sensitivity, electronics, quantum size effect and so on are to be solved at the same time. Characteristics of the existing instrument are being examined from various aspects. At present, the following three issues are taken up and being studied. (1) High resolution and related technical developments. (2) High sensitivity. (3) High performance of cooling system. Among them, the high resolution is the most serious problem. Completely new design of the SQUID system may be needed. By using the existing instrument, magnetic fluxes trapped on YBCO films are observed and the image quality is being examined. Some of the issues which are considered to be taken up now are listed as follows. (1) Magnetic domain structures on thin film magnetic materials. (2) Observation of structures of Josephson magnetic

Effect of Composition on Electrical and Optical Properties of Thin Films of Amorphous GaxSe100−x Nanorods

Directory of Open Access Journals (Sweden)

Abdallah El-Hamidy SM

2010-01-01

Full Text Available Abstract We report the electrical and optical studies of thin films of a-GaxSe100−x nanorods (x = 3, 6, 9 and 12. Thin films of a-GaxSe100−x nanorods have been synthesized thermal evaporation technique. DC electrical conductivity of deposited thin films of a-GaxSe100−x nanorods is measured as a function of temperature range from 298 to 383 K. An exponential increase in the dc conductivity is observed with the increase in temperature, suggesting thereby a semiconducting behavior. The estimated value of activation energy decreases on incorporation of dopant (Ga content in the Se system. The calculated value of pre-exponential factor (σ0 is of the order of 101 Ω−1 cm−1, which suggests that the conduction takes place in the band tails of localized states. It is suggested that the conduction is due to thermally assisted tunneling of the carriers in the localized states near the band edges. On the basis of the optical absorption measurements, an indirect optical band gap is observed in this system, and the value of optical band gap decreases on increasing Ga concentration.

Chemical bath deposition of Hg doped CdSe thin films and their characterization

International Nuclear Information System (INIS)

Bhuse, V.M.

2005-01-01

The deliberate addition of Hg in CdSe thin film have been carried out using a simple, modified, chemical bath deposition technique with the objective to study the effect of Hg doping on properties of CdSe thin films. Synthesis was initiated at 278 K temperature using complexed cadmium sulphate, mercuric nitrate and sodium selenosulphate in an aqueous ammonical medium at pH 10. Films were characterized by XRD, SEM, optical absorption, electrical and thermoelectric techniques. The 'as deposited' films were uniform, well adherent, nearly stoichiometric and polycrystalline in a single cubic phase (zinc blende). Crystallite size determined from XRD and SEM was found to increase slightly with addition of Hg. The optical band gap of CdSe remains constant upto 0.05 mol% Hg doping, while it decreases monotonically with further increase in mercury content. Dark dc electrical resistivity and conduction activation energy of CdSe were found to decrease initially upto 0.05 mol% of Hg, thereafter increased for higher values of Hg but remains less than those of CdSe. All the films showed n-type of conductivity. A CdSe film containing 0.05 mol% of Hg showed higher absorption coefficient, and conductivity

Mechanical and electrochemical characterization of vanadium nitride (VN) thin films

Energy Technology Data Exchange (ETDEWEB)

Caicedo, J.C., E-mail: Jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Departamento de Fisica, Universidad del Valle, Cali (Colombia); Zambrano, G. [Grupo de Peliculas Delgadas, Departamento de Fisica, Universidad del Valle, Cali (Colombia); Aperador, W. [Ingenieria Mecatronica, Universidad Militar Nueva Granada, Bogota (Colombia); Escobar-Alarcon, L.; Camps, E. [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico, DF 11801 (Mexico)

2011-10-15

Vanadium nitride (V-N) thin films were grown using a reactive d.c. magnetron sputtering process, from a vanadium target (99.999%) in an Ar/N{sub 2} gas mixture at different deposition bias voltage. Films were deposited onto silicon (1 0 0) and RUS-3 steel substrates at 400 deg. C. Structural, compositional, mechanical and electrochemical characterizations were performed by X-ray diffraction (XRD), elastic forward analysis (EFA), nanoindentation, electrochemical impedance spectroscopy (EIS), and Tafel polarization curves, respectively. X-ray diffraction patterns show the presence of (1 1 1) and (2 0 0) crystallographic orientations associated to the V-N cubic phase. Nanoindentation measurements revealed that when the bias voltage increases from 0 V to -150 V the hardness and elastic modulus are increased from 11 GPa to 20 GPa and from 187 GPa to 221 GPa, respectively. EIS and Tafel curves showed that the corrosion rate of steel, coated with V-N single layer films deposited without bias voltage, diminishes 90% compared to the steel without this coating. On the other hand, when the V-N coating was deposited at the highest d.c. bias voltage (-150 V), the corrosion rate was greater than in the steel coated with zero-voltage (0 V) V-N films. This last result could be attributed to the formation of porosities produced by the ion bombardment during the deposition process.

Mechanical and electrochemical characterization of vanadium nitride (VN) thin films

International Nuclear Information System (INIS)

Caicedo, J.C.; Zambrano, G.; Aperador, W.; Escobar-Alarcon, L.; Camps, E.

2011-01-01

Vanadium nitride (V-N) thin films were grown using a reactive d.c. magnetron sputtering process, from a vanadium target (99.999%) in an Ar/N 2 gas mixture at different deposition bias voltage. Films were deposited onto silicon (1 0 0) and RUS-3 steel substrates at 400 deg. C. Structural, compositional, mechanical and electrochemical characterizations were performed by X-ray diffraction (XRD), elastic forward analysis (EFA), nanoindentation, electrochemical impedance spectroscopy (EIS), and Tafel polarization curves, respectively. X-ray diffraction patterns show the presence of (1 1 1) and (2 0 0) crystallographic orientations associated to the V-N cubic phase. Nanoindentation measurements revealed that when the bias voltage increases from 0 V to -150 V the hardness and elastic modulus are increased from 11 GPa to 20 GPa and from 187 GPa to 221 GPa, respectively. EIS and Tafel curves showed that the corrosion rate of steel, coated with V-N single layer films deposited without bias voltage, diminishes 90% compared to the steel without this coating. On the other hand, when the V-N coating was deposited at the highest d.c. bias voltage (-150 V), the corrosion rate was greater than in the steel coated with zero-voltage (0 V) V-N films. This last result could be attributed to the formation of porosities produced by the ion bombardment during the deposition process.

Thin films for precision optics

International Nuclear Information System (INIS)

Araujo, J.F.; Maurici, N.; Castro, J.C. de

1983-01-01

The technology of producing dielectric and/or metallic thin films for high precision optical components is discussed. Computer programs were developed in order to calculate and register, graphically, reflectance and transmittance spectra of multi-layer films. The technology of vacuum evaporation of several materials was implemented in our thin-films laboratory; various films for optics were then developed. The possibility of first calculate film characteristics and then produce the film is of great advantage since it reduces the time required to produce a new type of film and also reduces the cost of the project. (C.L.B.) [pt

A three-axis SQUID-based absolute vector magnetometer

Energy Technology Data Exchange (ETDEWEB)

Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G. [Department of Quantum Detection, Leibniz Institute of Photonic Technology, Jena 07745 (Germany); Zakosarenko, V.; Meyer, M. [Supracon AG, An der Lehmgrube 11, Jena 07751 (Germany)

2015-10-15

We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

Investigation of the structural, optical and electrical transport properties of n-doped CdSe thin films

Science.gov (United States)

Ali, H. M.; Abd El-Ghanny, H. A.

2008-04-01

Thin films of (CdSe)90(In2O3)10, (CdSe)90(SnO2)10 and (CdSe)90(ZnO)10 have been grown on glass substrates by the electron beam evaporation technique. It has been found that undoped and Sn or In doped CdSe films have two direct transitions corresponding to the energy gaps Eg and Eg+Δ due to spin-orbit splitting of the valence band. The electrical resistivity for n-doped CdSe thin films as a function of light exposure time has been studied. The influence of doping on the structural, optical and electrical characteristics of In doped CdSe films has been investigated in detail. The lattice parameters, grain size and dislocation were determined from x-ray diffraction patterns. The optical transmittance and band gap of these films were determined using a double beam spectrophotometer. The DC conductivity of the films was measured in vacuum using a two-probe technique.

Investigation of Electrical, Optical and GaS Sensing properties Sol-Gel Derived WO3 Thin Films

International Nuclear Information System (INIS)

Dumludag, F.

2008-01-01

Tungsten oxide (WO 3 ) is a wide band gap n-type semiconductor. Thin films of WO 3 are considerable interest because of their potential applications in electrochromic devices, and gas sensors. In this work, WO 3 thin films were deposited on IDT (Interdigital electrodes) by a sol-gel dipping process. Precursor solution was prepared by dissolving of tungstic acid in ammonia. We investigated d.c. and a.c. (40 Hz-100 KHz) electrical properties of the films in the temperature range of 293K and 473K in vacuum ambient (10 - 2 mbar). We observed frequency dependent conductivity behavior at high frequencies. Absorption spectra of the film showed that a maximum absorption occurred at 330 nm. We also investigated the response of the films to vapors of the volatile organic compounds (acetone, chloroform, toluene, ethanol, ammonia) and water vapor. The films showed no sensitivity to the test gases at room temperature. Concentration of the vapors were controlled by mass flowmeters. All the measurement system was computerized

Thickness dependent structural, optical and electrical properties of Se85In12Bi3 nanochalcogenide thin films

Science.gov (United States)

Tripathi, Ravi P.; Zulfequar, M.; Khan, Shamshad A.

2018-04-01

Our aim is to study the thickness dependent effects on structure, electrical and optical properties of Se85In12Bi3 nanochalcogenide thin films. Bulk alloy of Se85In12Bi3 was synthesized by melt-quenching technique. The amorphous as well as glassy nature of Se85In12Bi3 chalcogenide was confirmed by non-isothermal Differential Scanning Calorimetry (DSC) measurements. The nanochalcogenide thin films of thickness 30, 60 and 90 nm were prepared on glass/Si wafer substrate using Physical Vapour Condensation Technique (PVCT). From XRD studies it was found that thin films have amorphous texture. The surface morphology and particle size of films were studied by Field Emission Scanning Electron Microscope (FESEM). From optical studies, different optical parameters were estimated for Se85In12Bi3 thin films at different thickness. It was found that the absorption coefficient (α) and extinction coefficient (k) increases with photon energy and decreases with film thickness. The optical absorption process followed the rule of indirect transitions and optical band gap were found to be increase with film thickness. The value of Urbach energy (Et) and steepness parameter (σ) were also calculated for different film thickness. For electrical studies, dc-conductivity measurement was done at different temperature and activation energy (ΔEc) were determined and found to be increase with film thickness.

Analysis of Hard Thin Film Coating

Science.gov (United States)

Shen, Dashen

1998-01-01

MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

Thin-film solar cell

NARCIS (Netherlands)

Metselaar, J.W.; Kuznetsov, V.I.

1998-01-01

The invention relates to a thin-film solar cell provided with at least one p-i-n junction comprising at least one p-i junction which is at an angle alpha with that surface of the thin-film solar cell which collects light during operation and at least one i-n junction which is at an angle beta with

Critical behavior of ferromagnetic La0.7Sr0.3CoO3 thin films

International Nuclear Information System (INIS)

Schwarz, T.

2007-07-01

The present thesis concentrates on the critical behavior of ferromagnetic La 0.7 Sr 0.3 CoO 3 thin films (LSCO) close to the magnetic phase transition. The LSCO thin films were prepared by pulsed laser deposition and optimized with respect to their structural and magnetic properties. For the characterization of the structural and magnetic characteristics various methods were used. By means of X-ray diffraction and electron microscopy the crystallinity and microstructure of the epitaxial films were examined, respectively. The analysis of the chemical composition was accomplished by Rutherford backscattering and energy dispersive X-ray diffraction (EDX). Parallel to the investigations of the LSCO films a low-temperature measuring system for electrical measurements in magnetic fields up to 8 T in a temperature range from 1.5 K to 300 K was developed and built up including the necessary control and measuring software. The central point of this work was dedicated to the characterization of the magnetic characteristics of the LSCO films. In comparison, single crystals and polycrystalline bulk samples were also available. At these samples temperature-dependent and isothermal magnetization measurements were accomplished by a SQUID magnetometer. To determine the critical behavior of the samples the critical exponents of the susceptibility and the spontaneous magnetization in the proximity of the ferromagnetic phase transition were determined. For the exact determination of the critical exponents from the experimental data an evaluation routine in Matlab on basis of the Arrott representation method was used. In addition to the investigations of the critical behavior, electrical transportation measurements and neutron reflection measurements with spin-polarized neutrons were performed. The investigations of this work show that, in contrast to the critical behavior of single-crystal LSCO volume samples where a three-dimensional Heisenberg behavior could be observed, the

Thin-Film Material Science and Processing | Materials Science | NREL

Science.gov (United States)

Thin-Film Material Science and Processing Thin-Film Material Science and Processing Photo of a , a prime example of this research is thin-film photovoltaics (PV). Thin films are important because cadmium telluride thin film, showing from top to bottom: glass, transparent conducting oxide (thin layer

Nanocrystal thin film fabrication methods and apparatus

Science.gov (United States)

Kagan, Cherie R.; Kim, David K.; Choi, Ji-Hyuk; Lai, Yuming

2018-01-09

Nanocrystal thin film devices and methods for fabricating nanocrystal thin film devices are disclosed. The nanocrystal thin films are diffused with a dopant such as Indium, Potassium, Tin, etc. to reduce surface states. The thin film devices may be exposed to air during a portion of the fabrication. This enables fabrication of nanocrystal-based devices using a wider range of techniques such as photolithography and photolithographic patterning in an air environment.

Measurement of full-field deformation induced by a dc electrical field in organic insulator films

Directory of Open Access Journals (Sweden)

Boudou L.

2010-06-01

Full Text Available Digital image correlation method (DIC using the correlation coefficient curve-fitting for full-field surface deformation measurements of organic insulator films is investigated in this work. First the validation of the technique was undertaken. The computer-generated speckle images and the measurement of coefficient of thermal expansion (CTE of aluminium are used to evaluate the measurement accuracy of the technique. In a second part the technique is applied to measure the mechanical deformation induced by electrical field application to organic insulators. For that Poly(ethylene naphthalene 2,6-dicarboxylate (PEN thin films were subjected to DC voltage stress and DIC provides the full-field induced deformations of the test films. The obtained results show that the DIC is a practical and robust tool for better comprehension of mechanical behaviour of the organic insulator films under electrical stress.

Pulsed Laser-Induced Effects in the Material Properties of Tungsten Thin Films

Energy Technology Data Exchange (ETDEWEB)

Evans, R [Centro de Investigacion CientIfica y de Educacion Superior de Ensenada, Km. 107 Carretera Tijuana-Ensenada, BC, 22860 (Mexico); Camacho-Lopez, S [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Km. 107 Carretera Tijuana-Ensenada, BC, 22860 (Mexico); Camacho-Lopez, M A [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon y Tollocan, Toluca Edo. de Mexico, 50110 (Mexico); Sanchez-Perez, C [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, UNAM, Apdo. Postal 70-186, Mexico DF 04510 (Mexico); Esparza-GarcIa, A [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, UNAM, Apdo. Postal 70-186, Mexico DF 04510 (Mexico)

2007-04-15

In this work we present evidence of photo-induced effects on crystalline Tungsten (W) films. A frequency doubled Nd:YAG (5ns) laser was used in our experiments. The W thin films were deposited on silicon substrates by the DC-sputtering technique using W (Lesker, 99.95% purity) targets in an argon atmosphere. The crystalline phase of the deposited W films was determined by X-ray diffraction. Our experimental results show clear evidence that several events take place as a consequence of exposure of the W films to the laser nanosecond pulses. One of those events has a chemical effect that results in a significant degree of oxidation of the film; a second event affects the structural nature of the initial W material, resulting into a material phase change; and a third event changes the initially homogeneous morphology of the film into an unexpected porous material film. As it has been confirmed by the experiments, all of these effects are laser fluence dependent. A full post exposure analysis of the W thin films included Energy Dispersive Spectrometry to determine the degree of oxidation of the W film; a micro-Raman system was used to explore and to study the transition of the crystalline W to the amorphous-crystalline WO{sub 3} phase; further analysis with Scanning Electron Microscopy showed a definite laser-induced porosity which changes the initial homogeneous film into a highly porous film with small features in the range from 100 to 300 nm.

Pulsed Laser-Induced Effects in the Material Properties of Tungsten Thin Films

International Nuclear Information System (INIS)

Evans, R; Camacho-Lopez, S; Camacho-Lopez, M A; Sanchez-Perez, C; Esparza-GarcIa, A

2007-01-01

In this work we present evidence of photo-induced effects on crystalline Tungsten (W) films. A frequency doubled Nd:YAG (5ns) laser was used in our experiments. The W thin films were deposited on silicon substrates by the DC-sputtering technique using W (Lesker, 99.95% purity) targets in an argon atmosphere. The crystalline phase of the deposited W films was determined by X-ray diffraction. Our experimental results show clear evidence that several events take place as a consequence of exposure of the W films to the laser nanosecond pulses. One of those events has a chemical effect that results in a significant degree of oxidation of the film; a second event affects the structural nature of the initial W material, resulting into a material phase change; and a third event changes the initially homogeneous morphology of the film into an unexpected porous material film. As it has been confirmed by the experiments, all of these effects are laser fluence dependent. A full post exposure analysis of the W thin films included Energy Dispersive Spectrometry to determine the degree of oxidation of the W film; a micro-Raman system was used to explore and to study the transition of the crystalline W to the amorphous-crystalline WO 3 phase; further analysis with Scanning Electron Microscopy showed a definite laser-induced porosity which changes the initial homogeneous film into a highly porous film with small features in the range from 100 to 300 nm

Robotic 3D SQUID imaging system for practical nondestructive evaluation applications

International Nuclear Information System (INIS)

Isawa, K.; Nakayama, S.; Ikeda, M.; Takagi, S.; Tosaka, S.; Kasai, N.

2005-01-01

A robotic three-dimensional (3D) scanning superconducting quantum interference device (SQUID) imaging system was developed for practical nondestructive evaluation (NDE) applications. The major feature of this SQUID-NDE system is that the SQUID sensor itself scans in 3D by traveling over the surface of an object during testing without the need for magnetic shielding. This imaging system consists of (i) DC-SQUID gradiometer for effective movement of the sensor, (ii) SQUID sensor manipulator utilizing an articulated-type robot used in industry, (iii) laser charge-coupled-device (CCD) displacement sensor to measure the 3D coordinates of points on the surface of the object, and (iv) computer-aided numerical interpolation scheme for 3D surface reconstruction of the object. The applicability of this system for NDE was demonstrated by successfully detecting artificial damage of cylindrical-shaped steel tubes

Development of natively textured surface hydrogenated Ga-doped ZnO-TCO thin films for solar cells via magnetron sputtering

International Nuclear Information System (INIS)

Wang, Fei; Chen, Xin-liang; Geng, Xin-hua; Zhang, De-kun; Wei, Chang-chun; Huang, Qian; Zhang, Xiao-dan; Zhao, Ying

2012-01-01

Highlights: ► Natively textured surface hydrogenated gallium-doped zinc oxide (HGZO) thin films have been deposited via magnetron sputtering on glass substrates. ► The directly deposited HGZO thin films present rough crater-type surface morphology. ► Typical HGZO thin film exhibits a high electron mobility of 41.3 cm 2 /V s and a relative low sheet resistance of ∼7.0 Ω. ► These HGZO thin films have high optical transmittances in the visible and near infrared region (∼380–1100 nm). ► A gradient H 2 growth method for fabricating HGZO thin films has been proposed in magnetron sputtering process. - Abstract: The main purposes are to obtain high quality transparent conductive oxide (TCO) based on zinc oxide (ZnO) thin films with high optical transparency in the visible and near infrared spectral range, high electrical conductivity and good light-scattering capability to enhance the path of the light inside the Si-based thin film solar cells. Natively textured surface hydrogenated gallium-doped ZnO (HGZO) thin films have been deposited via pulsed direct current (DC) magnetron sputtering on glass substrates at a substrate temperature of 553 K. These natively textured HGZO thin films exhibit high optical transmittance (over 80%) in the visible and near infrared region (λ = 380–1100 nm) and excellent electrical properties. The optimized HGZO thin film with crater-type textured surface obtained at the hydrogen flow rate of ∼2.0 sccm exhibits a high electron mobility of 41.3 cm 2 /V s and a relatively low sheet resistance of ∼7.0 Ω. The influences of hydrogen flow rates on the surface morphology, electrical and optical properties of HGZO thin films were investigated in detail. In addition, we put forward a method of gradient H 2 growth technique for fabricating HGZO thin films so as to obtain rough surface structure with good light-scattering capability and high electrical conductivity. “Crater-like” surface feature size and optical transmittance

Characteristics of tungsten oxide thin films prepared on the flexible substrates using pulsed laser deposition

International Nuclear Information System (INIS)

Suda, Yoshiaki; Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyuu, Yoshihito

2008-01-01

Tungsten trioxide (WO 3 ) thin films have been prepared on the flexible indium tin oxide (ITO) substrates by pulsed laser deposition (PLD) using WO 3 targets in oxygen gas. Color of the WO 3 film on the flexible ITO substrates depends on the oxygen gas mixture. The plasma plume produced by PLD using a Nd:YAG laser and WO 3 target is investigated by temporal and spatial-resolved optical emission spectroscopy. WO 3 films prepared on the flexible ITO substrates show electrochromic properties, even when the substrates are bent. The film color changes from blue to transparent within 10-20 s after the applied DC voltage is turned off

Analogy for the maximum obtainable colouration between electrochromic, gasochromic, and electrocolouration in DC-sputtered thin WO3-y films

International Nuclear Information System (INIS)

Stolze, M.; Gogova, D.; Thomas, L.-K.

2005-01-01

Tungsten oxide films with varied substoichiometry were deposited by reactive DC-sputtering from a W target at different oxygen partial pressures. The inherent maximum achievable electrochemical colouration and electrocolouration were found to be dependent on the oxygen content and consequently on the film substoichiometry. These results were related to those obtained in a previous study by colouration with hydrogen spillover from a catalyst (gasochromic colouration) of films fabricated in the same way. A clear analogy among the colouration by the three different techniques appeared

Bacterial adhesion studies on titanium, titanium nitride and modified hydroxyapatite thin films

Energy Technology Data Exchange (ETDEWEB)

Jeyachandran, Y L [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Venkatachalam, S [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Karunagaran, B [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Narayandass, Sa K [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Mangalaraj, D [Department of Physics, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Bao, C Y [West China College of Stomatology, Sichuan University, Chengdu 610041 (China); Zhang, C L [West China College of Stomatology, Sichuan University, Chengdu 610041 (China)

2007-01-15

A qualitative study on adhesion of the oral bacteria Porphyromonas gingivalis on titanium (Ti), titanium nitride (TiN), fluorine modified hydroxyapatite (FHA) and zinc modified FHA (Zn-FHA) thin films is investigated. Ti and TiN thin films were deposited by DC magnetron sputtering and hydroxyapatite-based films were prepared by solgel method. The crystalline structure, optical characteristics, chemical composition and surface topography of the films were studied by XRD, optical transmission, XPS, EDAX and AFM measurements. The predominant crystallite orientation in the Ti and TiN films was along (002) and (111) of hcp and cubic structures, respectively. The Ti : O : N composition ratio in the surface of the Ti and TiN films was found to be 7 : 21 : 1 and 3 : 8 : 2, respectively. The atomic concentration ratio (Zn + Ca) / P in Zn-FHA film was found to be 1.74 whereby the Zn replaced 3.2% of Ca. The rough surface feature in modified HA films was clearly observed in the SEM images and the surface roughness (rms) of Ti and TiN films was 2.49 and 3.5 nm, respectively, as observed using AFM. The film samples were sterilized, treated in the bacteria culture medium, processed and analyzed using SEM. Surface roughness of the films was found to have least influence on the bacterial adhesion. More bacteria were observed on the TiN film with oxide nitride surface layer and less number of adhered bacteria was noticed on the Ti film with native surface oxide layer and on Zn-FHA film.

Bacterial adhesion studies on titanium, titanium nitride and modified hydroxyapatite thin films

International Nuclear Information System (INIS)

Jeyachandran, Y.L.; Venkatachalam, S.; Karunagaran, B.; Narayandass, Sa.K.; Mangalaraj, D.; Bao, C.Y.; Zhang, C.L.

2007-01-01

A qualitative study on adhesion of the oral bacteria Porphyromonas gingivalis on titanium (Ti), titanium nitride (TiN), fluorine modified hydroxyapatite (FHA) and zinc modified FHA (Zn-FHA) thin films is investigated. Ti and TiN thin films were deposited by DC magnetron sputtering and hydroxyapatite-based films were prepared by solgel method. The crystalline structure, optical characteristics, chemical composition and surface topography of the films were studied by XRD, optical transmission, XPS, EDAX and AFM measurements. The predominant crystallite orientation in the Ti and TiN films was along (002) and (111) of hcp and cubic structures, respectively. The Ti : O : N composition ratio in the surface of the Ti and TiN films was found to be 7 : 21 : 1 and 3 : 8 : 2, respectively. The atomic concentration ratio (Zn + Ca) / P in Zn-FHA film was found to be 1.74 whereby the Zn replaced 3.2% of Ca. The rough surface feature in modified HA films was clearly observed in the SEM images and the surface roughness (rms) of Ti and TiN films was 2.49 and 3.5 nm, respectively, as observed using AFM. The film samples were sterilized, treated in the bacteria culture medium, processed and analyzed using SEM. Surface roughness of the films was found to have least influence on the bacterial adhesion. More bacteria were observed on the TiN film with oxide nitride surface layer and less number of adhered bacteria was noticed on the Ti film with native surface oxide layer and on Zn-FHA film

Characterizations of photoconductivity of graphene oxide thin films

Directory of Open Access Journals (Sweden)

Shiang-Kuo Chang-Jian

2012-06-01

Full Text Available Characterizations of photoresponse of a graphene oxide (GO thin film to a near infrared laser light were studied. Results showed the photocurrent in the GO thin film was cathodic, always flowing in an opposite direction to the initial current generated by the preset bias voltage that shows a fundamental discrepancy from the photocurrent in the reduced graphene oxide thin film. Light illumination on the GO thin film thus results in more free electrons that offset the initial current. By examining GO thin films reduced at different temperatures, the critical temperature for reversing the photocurrent from cathodic to anodic was found around 187°C. The dynamic photoresponse for the GO thin film was further characterized through the response time constants within the laser on and off durations, denoted as τon and τoff, respectively. τon for the GO thin film was comparable to the other carbon-based thin films such as carbon nanotubes and graphenes. τoff was, however, much larger than that of the other's. This discrepancy was attributable to the retardation of exciton recombination rate thanks to the existing oxygen functional groups and defects in the GO thin films.

Physical characterization of sputter-deposited amorphous tungsten oxynitride thin films

Energy Technology Data Exchange (ETDEWEB)

Nunez, O.R.; Moreno Tarango, A.J. [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Murphy, N.R. [Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base (WPAFB), Dayton, OH 45433 (United States); Phinney, L.C.; Hossain, K. [Amethyst Research Inc., 123 Case Circle, Ardmore, OK 73401 (United States); Ramana, C.V., E-mail: rvchintalapalle@utep.edu [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States)

2015-12-01

Tungsten oxynitride (W–O–N) thin films were deposited onto silicon (100) and quartz substrates using direct current (DC) sputtering. Composition variations in the W–O–N films were obtained by varying the nitrogen gas flow rate from 0 to 20 sccm, while keeping the total gas flow constant at 40 sccm using 20 sccm of argon with the balance comprised of oxygen. The resulting crystallinity, optical properties, and chemical composition of the DC sputtered W–O–N films were evaluated. All the W–O–N films measured were shown to be amorphous using X-ray diffraction. Spectrophotometry results indicate that the optical parameters, namely, the transmission magnitude and band gap (E{sub g}), are highly dependent on the nitrogen content in the reactive gas mixture. Within the W–O–N system, E{sub g} was able to be precisely tailored between 2.9 eV and 1.9 eV, corresponding to fully stoichiometric WO{sub 3} and highly nitrided W–O–N, respectively. Rutherford backscattering spectrometry (RBS) coupled with X-ray photoelectron spectroscopy (XPS) measurements indicate that the composition of the films varies from WO{sub 3} to W–O–N composite oxynitride films. - Highlights: • W–O–N films of ~ 100 nm thick were sputter-deposited by varying nitrogen gas flow rate. • Nitrogen incorporation into W-oxide is effective at or after 9 sccm flow rate of nitrogen. • The band gap significantly decreases from ~ 3.0 eV to ~ 2.1 eV with progressive increase in nitrogen content. • A composite oxide-semiconductor of W–O–N is proposed to explain the optical properties.

Observation and manipulation of magnetic domains in sol gel derived thin films of spinel ferrites

Science.gov (United States)

Datar, Ashwini A.; Mathe, Vikas L.

2017-12-01

Thin films of spinel ferrites, namely zinc substituted nickel, cobalt ferrite, and manganese substituted cobalt ferrite, were synthesized using sol-gel derived spin-coating techniques. The films were characterized using x-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscopy techniques for the analysis of structural, morphological and vibrational band transition properties, which confirm the spinel phase formation of the films. The magnetic force microscopy (MFM) technique was used to observe the magnetic domain structure present in the synthesized films. Further, the films were subjected to an external DC magnetic field of 2 kG to orient the magnetic domains and analyzed using an ex situ MFM technique.

Development of neutron diffuse scattering analysis code by thin film and multilayer film

International Nuclear Information System (INIS)

Soyama, Kazuhiko

2004-01-01

To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering

Fabrication and non-covalent modification of highly oriented thin films of a zeolite-like metal-organic framework (ZMOF) with rho topology

KAUST Repository

Shekhah, Osama

2015-01-01

Here we report the fabrication of the first thin film of a zeolite-like metal-organic framework (ZMOF) with rho topology (rho-ZMOF-1, ([In48(HImDC)96]48-)n) in a highly oriented fashion on a gold-functionalized substrate. The oriented rho-ZMOF-1 film was functionalized by non-covalent modification via post-synthetic exchange of different probe molecules, such as acridine yellow, methylene blue, and Nile red. In addition, encapsulation of a porphyrin moiety was achieved via in situ synthesis and construction of the rho-ZMOF. Adsorption kinetics of volatile organic compounds on rho-ZMOF-1 thin films was also investigated. This study suggests that rho-ZMOF-1 thin films can be regarded as a promising platform for various applications such as sensing and catalysis. This journal is

X-ray absorption fine structure (XAFS) studies of cobalt silicide thin films

International Nuclear Information System (INIS)

Naftel, S.J.; Coulthard, I.; Hu, Y.; Sham, T.K.; Zinke-Allmang, M.

1998-01-01

Cobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L 2,3 - and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi 2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi 2 . Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed