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The electrical properties of palladium chromium strain sensitive films with various thicknesses were fabricated onto sapphire substrates by direct current magnetron sputtering are investigated. The results show that the electrical properties of PdCr strain films are strongly dependent on their thickness. The square resistance and the temperature coefficient of resistance of PdCr strain sensitive films are dramatically decreased when the thickness of PdCr films that thinner than 232 nm, then the downward trend of electrical properties tends to be stabilized until 933 nm. The PdCr films with 933 nm thickness show a relative minimum temperature coefficient of resistance and excellent repeatability from room temperature to 800 °C. Furthermore, the stability of PdCr thin film strain gauges are measured at 600 and 800 °C by drift test, which reveals that the average resistance drift rate of PdCr strain film with 48 nm is almost ten times larger than that of the films with thickness of 933 nm. The above results further verify that the PdCr film with thickness of 933 nm possesses relatively superior electrical properties. Moreover, the strain response of PdCr thin film strain gauge with 933 nm on DZ22 Ni-based superalloys is studied, which indicates that the values of resistance are synchronous response to the strain implying the PdCr thin film strain gauge has a fast response to strain, and the gauge factor is 1.80, 1.88, 1.90 and 1.93 at 25, 400, 600 and 800 °C, respectively. [ABSTRACT FROM AUTHOR]

Thin film thermocouples could provide precise temperature measurement of the hot components of gas turbine engines with fast response in harsh environments. ITO thin films were prepared by radio frequency magnetron sputtering in pure argon atmosphere and annealed in air at 1000 °C. The variation of the microstructure and electrical properties of indium tin oxide thin films with annealing was disclosed. ITO/Pt thin film thermocouple was fabricated on Ni-based superalloy substrate by sputtering with stencil mask. And the thermoelectric performance and stability of the thin film thermocouples were characterized with temperature up to 1100 °C. [ABSTRACT FROM AUTHOR]

Refractory thin film thermocouples can provide more accurate surface temperature measurement and faster response with excellent chemical and electrical stability at high temperatures in harsh oxidizing environment. Indium tin oxide (ITO) thin films were fabricated by radio frequency magnetron sputtering in gas mixture of Ar and N. The introduction of nitrogen results in significant variations of the electrical and thermoelectric property of ITO thin films. This nitrogen doped ITO thin film was used as negative thermal element to form ITON:Pt thin film thermocouple on Ni-based superalloy substrate. The stability and thermoelectric performance of this thin film thermocouple was investigated up to 1000 °C. [ABSTRACT FROM AUTHOR]

β-GaO films prepared by metal organic deposition (MOD) on (000 l) sapphire substrates, have been developed for ultraviolet photodectors. The structural, surface, optical properties of MOD derived β-GaO films depending on growth temperatures were investigated. As growth temperature increased, the crystallinity of β-GaO films enhanced, crystallite size and surface roughness increased. The optical band gap of β-GaO films maintained within 4.8-4.9 eV at different growth temperatures. Metal-semiconductor-metal ultraviolet photodetectors based on MOD derived β-GaO films were successfully fabricated, demonstrating the responsivity of 0.76 A/W at 20 V and the upper limits of the rise and decay time of 50 and 30 ms, respectively, indicating a promising low-cost approach for GaO-base photoelectronics applications. [ABSTRACT FROM AUTHOR]

In order to avoid thermal destruction of the superconductor in case of overcurrent, and improve the engineering current density J of the tapes, a novel buffer architecture, i.e., conductive SrRuO/TiN, has been developed on biaxially textured Ni-5 at.%W substrate for YBaCuO (YBCO) coated conductors using pulsed laser deposition. The conductive TiN served as the effective seed and barrier layer because of low diffusion of metal atoms in the TiN layer, and the epitaxial conductive SrRuO with good lattice match with the YBCO material, and was used as the cap layer. The X-ray diffraction showed the TiN and SrRuO films had a perfect c-axis orientation and very good out-of-plane and in-plane texture. Atomic force microscopy indicated a very flat and dense TiN film with a layer-by-layer growth mode, and the root mean square surface roughness ( R) of the SrRuO was less than 5 nm over a 2 μm × 2 μm scan area. The current-voltage curves of SRO/TiN/NiW showed a good conductivity of 16.7 Ω at the applied voltage of zero. [ABSTRACT FROM AUTHOR]

The composition and microstructure of sandwich structure Al 2 O 3 /Si 3 N 4 /YAlO multilayer films deposited by magnetron sputtering were investigated. The results of X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) show that α-SiAlON and Y-doped α-SiAlON are formed at the interface of Al 2 O 3 /Si 3 N 4 and Si 3 N 4 /YAlO respectively after nitrogen annealing at 1300 °C. The thermoelectric properties of S-type (Pt/Pt–10%Rh) thin film thermocouples (TFTCs) with Al 2 O 3 and Al 2 O 3 /Si 3 N 4 /YAlO protective layers deposited by magnetron sputtering were investigated from 700 °C to 1550 °C. The high temperature static calibration results show that the thermoelectric performance of TFTCs with an Al 2 O 3 protective layer begins to decline at 1350 °C, the drift rate of the TFTCs is 13.27 °C/h, and the TFTCs fail at 1550 °C. However, the drift rate of TFTCs with an Al 2 O 3 /Si 3 N 4 /YAlO protective layer is only 2.19 °C/h at 1350 °C, and the performance begins to decline significantly at 1550 °C with a drift rate of 82.89 °C/h. The S-type TFTCs with sandwich structure Al 2 O 3 /Si 3 N 4 /YAlO multilayer provides a good prospect for the application of TFTCs in ultra-high temperature environment. [ABSTRACT FROM AUTHOR]

Platinum (Pt) thin-film resistance temperature detector was fabricated on the flexible Hastelloy tapes using magnetron sputtering and MEMS processes. NiCrAlY buffer layer and AlON/Al 2 O 3 insulating layer were deposited on the tapes for stress release and electrical insulation. Post annealing was applied to improve the stability of the sensors. The performance of the sensor was calibrated with temperature up to 550 °C. Compared with the sensor on the alumina ceramic substrate, the sensor on Hastelloy tapes have much smaller thermal hysteresis, higher linearity and excellent stability. Moreover, this flexible sensor can be easily integrated with the metallic components by the welding and the maximum curvature of the sensor is 2 cm−1. This Pt thin-film temperature sensor has great potential in the surface temperature measurement of hot components in harsh environment. • This Hastelloy tape based RTD has small thermal hysteresis, higher linearity and excellent stability. • AlON/Al 2 O 3 structure ensures the electrical insulation between the Pt film and the metallic substrate. • This flexible sensor can be easily integrated with metallic components for surface temperature measurement. [ABSTRACT FROM AUTHOR]

Nitrogen doped indium tin oxide (ITO) and platinum thin films were fabricated on alumina substrate by magnetron sputtering and formed thin film thermocouples (TFTCs) with stencil mask. After annealing in N 2 or air, the thermoelectric properties of the TFTCs were calibrated for multiple cycles with different calibration atmospheres. The Seebeck coefficient of ITO thin films at high temperature was obtained. The element segregation and oxygen vacancy was stabilized by the formation of oxynitrides in ITO films. And their effects on the Seebeck coefficient of ITO films was discussed. • The Seebeck coefficient of ITO films at high temperature is dictated by the oxygen diffusion. • The formation of oxynitrides could stabilize the oxygen vacancy of ITO films. • The Seebeck coefficient of ITON films demonstrates excellent reproducibility. [ABSTRACT FROM AUTHOR]

In this paper, hydrogen ions doping is used to construct lattice defects in AlN thin films. Effects of hydrogen ions doping on the lattice structure, components, and defects of AlN thin films were analyzed. SIMS results show several main types of point defects formed in hydrogen ions doped AlN thin films. XPS spectra find many nitrogen-vacancy defects on the surface of AlN thin films. These point defects make Raman scattered photons fall, thus weakening Raman scattering intensity. High-resolution TEM image shows abundant dislocation defects. Lattice defects produced by hydrogen ions doping make the lattice structure of AlN thin films stretched along the c-axis. The X-ray diffraction peak of the (002) crystal plane of the AlN thin films shifts to the left seriously. The lattice defects caused by hydrogen ions doping are repaired at high temperatures, and then the lattice of the AlN thin films shrinks, which leads to the recovery of the X-ray diffraction peak position. The X-ray diffraction angle increases linearly with temperature and time. The linear variation relationship can be used for temperature interpretation. • Hydrogen ions doped AlN thin film is used as a sensitive material for temperature interpretation. • X-ray diffraction angle of annealed hydrogen ions doped AlN thin film increases linearly with annealing temperature and time. • The relationship between XRD diffraction angle and temperature is used as the basis for temperature interpretation. [ABSTRACT FROM AUTHOR]

In order to measure the surface temperature of aerospace hot-end components accurately, AlN thin film temperature measurement technology was explored. In this research, C-axis preferred orientation AlN thin film was deposited on Ni-based superalloy substrates by medium frequency (MF) reaction magnetron sputtering. Effect of temperature on the lattice structure of AlN thin film was studied. X-ray diffraction results show that the diffraction angles (2 θ) of AlN thin films shift to the left side monotonously with the increase of annealing temperature and annealing time. Based on this phenomenon, the maximum temperature experienced by the film can be deduced according to 2 θ values. A temperature interpretation algorithm equation was established with MATLAB. The algorithm is a binary linear equation, whose dependent variable is 2 θ and the independent variables are annealing temperature and annealing time. Then, temperature interpretation software was developed with Visual Studio 2019. The temperature interpretation range is 700–1200 °C and the relative interpretation error is less than 4.26%. [ABSTRACT FROM AUTHOR]

Abstract: Tb doped PbTiO3 (PT) thin films were prepared on ITO/glass substrates by sol–gel method. XRD was used to investigate the phase status of the thin films. It is shown that through rapid thermal process, the perovskite phase PbTiO3 thin films with highly (100) preferred orientation could be formed on the astatic ITO/glass substrates when Tb is doped into PbTiO3 system. The (100) preferred orientation of Tb-doped PbTiO3 films is attributed to the heterogeneous nucleation mechanism of the perovskite PbTiO3 phase induced by Tb doping and rapid thermal preparation process. It is successfully explained according to this mechanism that the content of the (100) oriented Tb-doped perovskite phase in PbTiO3 films varies with Tb doping concentration. An optimal doping concentration of Tb to achieve highly (100) oriented and well-crystallized PbTiO3 films is discovered. And a theoretical equation of the perovskite phase content as a function of Tb doping concentration is deduced. [Copyright &y& Elsevier]

Abstract: We report the laser-induced voltage (LIV) effects in c-axis oriented Bi2Sr2Co2O y thin films grown on (001) LaAlO3 substrates with the title angle α of 0°, 3°, 5° and 10° by a simple chemical solution deposition method. A large open-circuit voltage with the sensitivity of 300mV/mJ is observed for the film on 10° tilting LaAlO3 under a 308nm irradiation with the pulse duration of 25ns. When the film surface is irradiated by a 355nm pulsed laser of 25ps duration, a fast response with the rise time of 700ps and the full width at half maximum of 1.5ns is achieved. In addition, the experimental results reveal that the amplitude of the voltage signal is approximately proportional to sin2α and the signal polarity is reversed when the film is irradiated from the substrate side rather than the film side, which suggests the LIV effects in Bi2Sr2Co2O y thin films originate from the anisotropic Seebeck coefficient of this material. [ABSTRACT FROM AUTHOR]

Solution deposition planarisation (SDP), a novel surface modification method, was applied for the enhancement of flux pinning in superconducting thin films for the first time. Solution-derived amorphous Y 2 O 3 films were spin-coated on LaAlO 3 (LAO) substrates to modify substrates’ surface before sputtering YBa 2 Cu 3 O 7− δ (YBCO) films. The effect of the concentration of the precursor solution on the surface roughness and superconducting properties of the YBCO films was studied. It is found that the crystallinity and self-field properties of the YBCO films were improved because of the resulting reduction in roughness when the concentration of the precursor solution was properly chosen. As increasing the precursor concentrations, self-field critical current densities ( J c ) were deteriorated and the superconducting properties in magnetic fields were improved. In addition, dislocation densities in YBCO films induced by amorphous Y 2 O 3 were measured and quantitatively calculated. The relationship between the dislocation density and power-law exponent α (proportional factor of J c ∼ H − α ) was systematically investigated. The surface planarisation and defect-induced flux pinning behaviour of amorphous Y 2 O 3 films led to potential applications in low cost YBCO coated conductors. [ABSTRACT FROM AUTHOR]

Highlights: [•] c-Axis oriented Na0.68CoO2:Ag composite thin films with nanosized Ag particles well dispersed in the Na0.68CoO2 matrix have been fabricated. [•] The power factor of Na0.68CoO2/5wt.% Ag nanocomposite thin film is about 2 times higher than that of the Ag-free film. [•] Adding metallic nanoinclusions is a promising way to improve the thermoelectric performance of Na x CoO2 films. [Copyright &y& Elsevier]

[Display omitted] • The response of PdNi nano-film H 2 sensor can be modulated by the film thickness. • The relationship between H 2 concentration, thickness and sensing response was fitted. • The Sieverts' coefficient of PdNi film H 2 sensor is a function of the film thickness. • The limit of detection of 12 nm PdNi H 2 sensor is as low as 50 ppb. Resistive hydrogen sensors based on PdNi nano-film with different thicknesses were fabricated by Micro-Electro-Mechanical System technology. It demonstrates that the response of the PdNi nano-film hydrogen sensors continuously increases as the film thickness decreases within the experimental range. The response to 2.5 ppm hydrogen of 12 nm PdNi sensor is 4 times higher than that of 145 nm, and the detected limit of 12 nm is low to 50 ppb hydrogen. Reducing the film thickness doesn't affect the crystal structure, but reduces the crystallinity and grain size and increases the grain boundary density significantly. Thus, the thinner film possesses a higher volume fraction of the distorted part around the grain boundary to react with hydrogen. Meanwhile the thinner film has fewer barriers for hydrogen to transfer to the inside. When the hydrogen concentration is below 50 ppm, the relationship between the sensing response, hydrogen concentration and the film thickness is well fitted through linear regression method. The results agree with the Sieverts' law that the response is proportional to the one-half of the gas concentration, and the Sieverts' coefficient is a function of film thickness. [ABSTRACT FROM AUTHOR]

• Al 2 O 3 /ZrB 2 thin films exhibit a favorable thermal stability at 600 °C for 30 h. • Al 2 O 3 /ZrB 2 thin films exhibit a high average infrared reflectance of 0.86 after annealing at 750 °C for 2 h. • Al 2 O 3 thin film can effectively prevent diffusion of oxygen atoms during the heat treatment process. In the present research, ZrB 2 thin films and Al 2 O 3 /ZrB 2 multilayer were deposited on silicon substrates using magnetron sputtering method. To investigate the thermal stability of the thin films, films were annealed at temperatures of 600 °C, 700 °C and 800 °C, respectively. Results from X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectrometer (FTIR) suggested that ZrB 2 thin films were severely oxidized at 700 °C for 2 h which caused the obvious increase of infrared emissivity. In contrast, double-layer-structure Al 2 O 3 /ZrB 2 thin films exhibited a low infrared emissivity of 0.16 after annealing at 750 °C for 2 h. Similarity, ZrB 2 thin films showed a rise of infrared emissivity after annealing at 600 °C for 10 h. However, double-layer-structure Al 2 O 3 /ZrB 2 thin films exhibited a favorable thermal stability at 600 °C for 30 h with a low average infrared emissivity of 0.13 in the waveband of 2–14 μm. Compared with ZrB 2 thin films, double-layer-structure Al 2 O 3 /ZrB 2 thin films could work as low infrared emissivity layers at higher temperature for longer time for the reason that the addition of Al 2 O 3 thin film can effectively prevent diffusion of oxygen in air during the heat treatment process. [ABSTRACT FROM AUTHOR]

• ZrB 2 thin films can be used as low infrared emissivity layers at high temperature. • ZrB 2 thin films exhibits a low infrared emissivity of 0.01(8~14 μm) after heat treatment. • ZrB 2 thin film is a good contender to nobal metallic films. Zirconium diboride exhibits high thermal conductivities and high melting point, which are beneficial for use in extreme environments. Examples including cutting tools, high-temperature electrodes and leading edges of hypersonic space vehicles. However, there is limited literature on the infrared properties of ZrB 2 thin films. In this study, we report the results of infrared emissivity of sputter-deposited films and post-annealed films. X-ray diffraction shows promoted crystalline quality and grains growth for ZrB 2 films with the increasing annealing temperature and time. The thin film exhibits high thermal stability and a low infrared emissivity of 0.01 (8 ~ 14 μm) after annealed at 1000℃ for 10 h. Besides, with an increase in annealing temperature and annealing time, film densification and grains growth were observed, leading to decrease of electrical resistivity and infrared emissivity. [ABSTRACT FROM AUTHOR]