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1.
CuIn1 − xAlxSe2 (CIAS) thin films (x = 0.06, 0.18, 0.39, 0.64, 0.80 and 1) with thicknesses of approximately 1 μm were formed by the selenization of sputtered Cu―In―Al precursors and studied via X-ray diffraction, inductively coupled plasma mass spectrometry and micro-Raman spectroscopy at room temperature. Precursor films selenized at 300, 350, 400, 450, 500 and 550 °C were examined via Raman spectroscopy in the range 50-500 cm− 1 with resolution of 0.3 cm− 1. Sequential formation of InxSey, Cu2 − xSe, CuInSe2 (CIS) and CIAS phases was observed as the selenization temperature was increased. Conversion of CIS to CIAS was initiated at 500 °C. For all CuIn1 − xAlxSe2 products, the A1 phonon frequency varied nonlinearly with respect to the aluminum composition parameter x in the range 172 cm− 1 to 186 cm− 1.  相似文献   

2.
To examine variations in the transparent conducting properties after annealing at high temperatures, 300-nm thick Sb-doped Sn1 − xHfxO2 (x = 0.00-0.10) films were deposited onto silica glass substrates by the RF sputtering method and annealed in air up to 1000 °C at 200 °C increments. After annealing, all the Sb-doped SnO2 films were transparent and electrically conductive, but large cracks, which decreased the electrical conductivity, were generated in several films due to crystallization or the thermal expansion difference between the film and substrate. Only the film deposited at room temperature in an Ar and O2 mixed atmosphere did not crack after annealing, and its electrical conductivity exceeded 100 S cm− 1 even after annealing at 1000 °C in air. Hf-doping blue shifted the fundamental absorption edges in the UV region in the Sb-doped Sn1 − xHfxO2 films. Additionally, the optical transmission at 310 nm, T310, increased as the Hf concentration increased, whereas the electrical conductivity was inversely proportional to the Hf concentration. On the other hand, thinner films (150-nm thick) with x = 0.00 showed both a high electrical conductivity over 100 S cm− 1 and a high transparency T310 = 65% after high temperature annealing.  相似文献   

3.
Single-phase eskolaite crystalline Cr2 − xTixO3 films (CTO) with a uniform porous microstructure were fabricated via an electrostatic spray assisted vapour deposition (ESAVD) method. The sensing behavior upon exposure to ammonia and ethanol was characterized in a CTO film-based sensor device in terms of response, reproducibility, humidity constraints and sensor stability. The ESAVD process has been shown to be capable of producing CTO films at low temperature (650 °C) and more importantly, it results in a more uniform titanium distribution and better microstructural control than processes based on solid-state chemical reactions. The material with a nominal composition of Cr1.7Ti0.3O3 exhibited the highest sensitivity among the different Cr2 − xTixO3 compositions examined towards ammonia over the temperature range of 200-500 °C with a peak sensitivity of 2.90 at 200 °C. The CTO materials, when used as sensors, also exhibit excellent responses to ethanol concentration in air. The sensitivity was 0.64 for 10 ppm ethanol, 0.85 for 25 ppm, and 0.92 for 50 ppm, respectively.  相似文献   

4.
The optical and electrical properties of vapour phase grown crystals of diluted magnetic semiconductor Zn1 − xCrxTe were investigated for 0 ≤ x ≤ 0.005. The diffuse reflectance spectra exhibited an increase in the fundamental absorption edge (E0) with composition x and were also dominated by a broad absorption band around 5200 cm− 1 arising from 5T2 → 5E transition. The 5T2 and 5E levels originate from the crystal field splitting of the 5D free ion in the ground state. The electrical resistivity measurements revealed semiconducting behaviour of the samples with p-type conductivity in the temperature range of 200-450 K.  相似文献   

5.
CuIn1 − xGaxTe2 thin films with x = 0, 0.5 and 1, have been prepared by flash evaporation technique. These semiconducting layers present a chalcopyrite structure. The optical measurements have been carried out in the wavelength range 200-3000 nm. The linear dependence of the lattice parameters as a function of Ga content obeying Vegard's law was observed. The films have high absorption coefficients (4 · 104 cm− 1) and optical band gaps ranging from 1.06 eV for CuInTe2 to 1.21 eV for CuGaTe2. The fundamental transition energies of the CuIn1 − xGaxTe2 thin films can be fitted by a parabolic equation namely Eg1(x) = 1.06 + 0.237x − 0.082x2. The second transition energies of the CuInTe2 and CuGaTe2 films were estimated to be: Eg2 = 1.21 eV and Eg2 = 1.39 eV respectively. This variation of the energy gap with x has allowed the achievement of absorber layers with large gaps.  相似文献   

6.
Ti-modified thin films of multiferroic 0.72Bi(Fe1  xTix)O3-0.28PbTiO3 (BFPT, = 0 and 0.02) solid solution were prepared by pulsed laser deposition. The BFPT (= 0 and 0.02) films possess a tetragonal structure with highly preferential (001) orientation. The effects of the ionic substitution on the properties of BFPT (= 0 and 0.02) films have been investigated. The leakage current of the BFPT (= 0.02) thin film is significantly reduced, and the dielectric and ferroelectric properties greatly improved by the aliovalent ionic substitution of Ti4+ for Fe3+. The BFPT (= 0.02) thin film exhibits a reasonably high remnant polarization Pr with 2Pr up to 90 μC/cm2 at 312 kV/cm and a switchable polarization up to 92 μC/cm2 at 417 kV/cm.  相似文献   

7.
Thin films of Bi3.15Nd0.85Ti3O12 (BNT) and Bi3.15Nd0.85Ti3 − xZrxO12 (BNTZx, x = 0.1 and 0.2) were fabricated on Pt/TiO2/SiO2/Si(100) substrates by a chemical solution deposition (CSD) technique at 700 °C. Structures, surface morphologies, leakage current characteristics and Curie temperature of the films were studied as a function of Zr ion content by X-ray diffraction, atomic force microscopy, ferroelectric test system and thermal analysis, respectively. Experimental results indicate that Zr ion substitution in the BNT film markedly decreases the leakage current of the film, while almost not changing the Curie temperature of the film, which is at about 420-460 °C. The decrease of the leakage current in BNTZx films is that the conduction by the electron hopping between Ti4+ and Ti3+ ions is depressed because Zr4+ ions can block the path between two adjacent Ti ions and enlarge hopping distance.  相似文献   

8.
The effect of alloying and expitaxial mismatch strain on the surface ultraviolet (UV) emission efficiencies of AlxGa1 − xN films, pseudomorphically grown on both c- and m-plane AlyGa1 − yN templates (x < y) for various Al-content combinations, has been investigated under the framework of k·p perturbation theory. The results indicate that the film/template Al-content combination with y > − 0.03 + 1.79x−0.06x2 (0 < x < y < 1) for the c-plane case and the film/template with all y:x (0 < x < y < 1) combinations for the m-plane case, are particularly suitable for obtaining efficient UV light emissions. In the latter case, it's also ideal for fabricating edge-emitting UV devices with predominant transverse electric mode. Furthermore, polarized emissions with high polarization degree can be achieved by properly tuning the y:x ratio for certain x.  相似文献   

9.
The Gd2(TixZr1 − x)2O7 (x = 0, 0.25, 0.50, 0.75, 1.00) ceramics were synthesized by solid state reaction at 1650 °C for 10 h in air. The relative density and structure of Gd2(TixZr1 − x)2O7 were analyzed by the Archimedes method and X-ray diffraction. The thermal diffusivity of Gd2(TixZr1 − x)2O7 from room temperature to 1400 °C was measured by a laser-flash method. The Gd2Zr2O7 has a defect fluorite-type structure; however, Gd2(TixZr1 − x)2O7 (0.25 ≤ x ≤ 1.00) compositions exhibit an ordered pyrochlore-type structure. Gd2Zr2O7 and Gd2Ti2O7 are infinitely soluable. The thermal conductivity of Gd2(TixZr1 − x)2O7 increases with increasing Ti content under identical temperature conditions. The thermal conductivity of Gd2(TixZr1 − x)2O7 first decreases gradually with the increase of temperature below 1000 °C and then increases slightly above 1000 °C. The thermal conductivity of Gd2(TixZr1 − x)2O7 is within the range of 1.33 to 2.86 W m− 1 K− 1 from room temperature to 1400 °C.  相似文献   

10.
We report the discovery of a face-centered cubic (Al1−xCrx)2O3 solid solution [0.60 < x < 0.70] in films grown onto Si substrates using reactive radio frequency magnetron sputtering from Al and Cr targets at 400 °C. The proposed structure is NaCl-like with 33% vacancies on the metal sites. The unit cell parameter is 4.04 Å as determined by X-ray diffraction. The films have a <100> preferred crystallographic orientation and exhibit hardness values up to 26 GPa and an elastic modulus of 220-235 GPa.  相似文献   

11.
Up to 10 at.% of copper readily substitutes for cerium in ceria. It is found that at oxygen partial pressures between 0.21 atm and 10−5 atm, CuxCe1−xO2−δ (0 ≤ x ≤ 0.10) solid solution behave as an oxide-ion electrolyte. Interestingly, Cu0.10Ce0.90O2−δ exhibits the oxide-ion conductivity of ca. 10−4 Ω−1 cm−1 at 600 °C at an oxygen partial pressure of 10−5 atm.  相似文献   

12.
This paper describes the synthesis and characterization of CuIn1 − xGaxSe2 − ySy (CIGSeS) thin-film solar cells prepared by rapid thermal processing (RTP). An efficiency of 12.78% has been achieved on ~ 2 µm thick absorber. Materials characterization of these films was done by SEM, EDS, XRD, and AES. J-V curves were obtained at different temperatures. It was found that the open circuit voltage increases as temperature decreases while the short circuit current stays constant. Dependence of the open circuit voltage and fill factor on temperature has been estimated. Bandgap value calculated from the intercept of the linear extrapolation was 1.1-1.2 eV. Capacitance-voltage analysis gave a carrier density of 4.0 × 1015 cm− 3.  相似文献   

13.
Thin films of ferroelectric relaxor Pb1 − 3x/2LaxZr0.2Ti0.8O3, x = 0.22 have been integrated in an oxidic heterostructure for electro-optical investigations. The quadratic electro-optic behavior and optical properties have been studied by means of variable angle spectroscopic ellipsometry method in reflection mode. Birefringence values up to δΔ = 0.17° have been obtained for quadratic compositions at λ = 540 nm and 65° angle of incidence. Structural, chemical and morphologic properties of Pb1-3x/2LaxZr0.2Ti0.8O3 (x = 0.22) thin films have been investigated by x-ray diffraction and atomic force microscopy techniques. The dielectric and ferroelectric behavior has been investigated using dielectric spectroscopy and a ferroelectric test system.  相似文献   

14.
The grain size and the density of the Zn1 − xSnxO (0 ≤ x ≤ 0.05) samples decreased with increasing SnO2 content. The addition of a small amount of SnO2 (x ≤ 0.01) to ZnO led to an increase in both the electrical conductivity and the absolute value of the Seebeck coefficient, resulting in a significant increase in the power factor. The thermoelectric power factor was maximized to a value of 1.25 × 10−3 Wm−1 K−2 at 1073 K for the Zn0.99Sn0.01O sample.  相似文献   

15.
Single-crystalline Ti1−xNbxO2 (x = 0.2) films of 40 nm thickness were deposited on SrTiO3 (100) substrates by the pulsed laser deposition (PLD) technique. X-ray diffraction measurement confirmed epitaxial growth of anatase (001) film. The resistivity of Ti1−xNbxO2 films with x ≥ 0.03 is 2-3 × 10− 4 Ω cm at room temperature. The carrier density of Ti1−xNbxO2, which is almost proportional to the Nb concentration, can be controlled in a range of 1 × 1019 to 2 × 1021 cm− 3. Optical measurements revealed that internal transmittance in the visible and near-infrared region for films with x = 0.03 was more than 97%. These results demonstrate that the presently developed anatase Ti1−xNbxO2 is one of the promising candidates for the practical TCOs.  相似文献   

16.
Li3 − xFe2 − xTix(PO4)3/C (x = 0-0.4) cathodes designed with Fe doped by Ti was studied. Both Li3Fe2(PO4)3/C (x = 0) and Li2.8Fe1.8Ti0.2(PO4)3/C (x = 0.2) possess two plateau potentials of Fe3+/Fe2+ couple (around 2.8 V and 2.7 V vs. Li+/Li) upon discharge observed from galvanostatic charge/discharge and cyclic voltammetry. Li2.8Fe1.8Ti0.2(PO4)3/C has higher reversibility and better capacity retention than that of the undoped Li3Fe2(PO4)3/C. A much higher specific capacity of 122.3 mAh/g was obtained at C/20 in the first cycle, approaching the theoretical capacity of 128 mAh/g, and a capacity of 100.1 mAh/g was held at C/2 after the 20th cycle.  相似文献   

17.
Interfacial reactions and electrical properties of RF sputter deposited HfTaOx high-k gate dielectric films on Si1 − xGex (x = 19%) are investigated. X-ray photoelectron spectroscopic analyses indicate an interfacial layer containing GeOx, Hf silicate, SiOx (layer of Hf-Si-Ge-O) formation during deposition of HfTaOx. No evidence of Ta-silicate or Ta incorporation was found at the interface. The crystallization temperature of HfTaOx film is found to increase significantly after annealing beyond 500 °C (for 5 min) along with the incorporation of Ta. HfTaOx films (with 18% Ta) remain amorphous up to about 500 °C anneal. Electrical characterization of post deposition annealed (in oxygen at 600 °C) samples showed; capacitance equivalent thickness of ~ 4.3-5.7 nm, hysteresis of 0.5-0.8 V, and interface state density = 1.2-3.8 × 1012 cm− 2 eV− 1. The valence and conduction band offsets were determined from X-ray photoelectron spectroscopy spectra after careful analyses of the experimental data and removal of binding energy shift induced by differential charging phenomena occurring during X-ray photoelectron spectroscopic measurements. The valence and conduction band offsets were found to be 2.45 ± 0.05 and 2.31 ± 0.05 eV, respectively, and a band gap of 5.8 ± 05 eV was found for annealed samples.  相似文献   

18.
A bismuth and lead oxide based perovskite ternary solid solution xBi(Zn1/2Ti1/2)O3 − yPbZrO3 − zPbTiO3 (xBZT − yPZ − zPT) was investigated as an attempt to develop a high TC ferroelectric material for piezoelectric sensor and actuator applications. A morphotropic phase boundary (MPB) between rhombohedral and tetragonal phases was determined through an XRD study on a pseudobinary line 0.1BZT − 0.9[xPT − (1 − x)PZ] for composition 0.1Bi(Zn1/2Ti1/2)O3 − 0.5PbZrO3 − 0.4PbTiO3. Enhanced piezoelectric and ferroelectric activities were observed for MPB composition with dielectric constant εr′ ~ 23,000 at Curie temperature (TC) ≈ 320 °C, remanent polarization (Pr) = 35 μC/cm2, piezoelectric coefficient (d33) = 300 pC/N, unipolar strain = 0.15%, and electromechanical coupling coefficient (kP) = 0.45.  相似文献   

19.
Transparent conducting thin films of Al-doped and Ga-doped Zn1 − xMgxO with arbitrary Mg content x were deposited on glass substrates by simultaneous RF-magnetron sputtering of doped ZnO and MgO targets, and their fundamental properties were characterized. MgO phase separation in Zn1 − xMgxO films was not detected by X-ray diffraction. The Zn1 − xMgxO films show high optical transparency in the visible region. Although the carrier density of the Zn1  xMgxO films decreased with increasing x, the Zn1 − xMgxO films showed good electrical conductivity; electrical resistivity as low as 8 × 10− 4 Ω ·cm was achieved for the Zn0.9Mg0.1O:Ga thin film.  相似文献   

20.
We proposed the low temperature formation technique of strain-relaxed Si1 − x − yGexSny-on-insulator (SGTOI) structures. We found that the solid-phase reaction and the formation of single and uniform Si1 − x − yGexSny layer on an insulator after annealing SiO2/Ge1 − zSnz/SOI structures even at a temperature as low as 400 °C. We characterized the crystalline structure of SGTOI, and investigated the effects of annealing, Sn incorporation, and a SiO2 cap layer on the solid-phase reaction between Ge1 − zSnz and SOI layers. The solid-phase reaction is enhanced with a higher Sn content and a thicker SiO2 cap layer, and then Si1 − x − yGexSny layers are more rapidly formed. The SGTOI layer exhibits very low mosaicity and have good crystallinity.  相似文献   

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