An automated thin-layer flow cell electrodeposition system was developed for growing Bi2Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt, ...An automated thin-layer flow cell electrodeposition system was developed for growing Bi2Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt, this reductive Te underpotential deposition （UPD）/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4∶3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO+2 reduction excludes the possibility of Bi2Te3 formation. X-ray photoelectron spectroscopy （XPS） analysis also reveals that the incomplete charge transfer in HTeO+2 occurs in Te direct deposition. The effective way of depositing Bi2Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. A polycrystalline characteristic was confirmed by XRD. The 2∶3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about （0.30.4 μm） in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.展开更多
The thin film gas sensors of bismuth iron molybdate were prepared by ion beam sputtering technique. The prototype gas sensors studied have high sensitivity and selectivity to reducing gases, such as ethanol vapor, s...The thin film gas sensors of bismuth iron molybdate were prepared by ion beam sputtering technique. The prototype gas sensors studied have high sensitivity and selectivity to reducing gases, such as ethanol vapor, show a long term stability of response under most operating conditions and insensitivity to atmospheric humidity, and respond quickly comparing to traditional sintered gas sensors. The crystallographic structure and phase composition of these thin films were investigated with XRD, XPS and SEM techniques.展开更多
Bi2Se3 thin films were electrochemically deposited on Ti and indium tin oxide-coated glass substrates, respectively, at room temperature, using Bi（NO3）3·5H2O and SeO2 as starting materials in diluted HNO3 solut...Bi2Se3 thin films were electrochemically deposited on Ti and indium tin oxide-coated glass substrates, respectively, at room temperature, using Bi（NO3）3·5H2O and SeO2 as starting materials in diluted HNO3 solution. A conventional three-electrode cell was used with a platinum sheet as a counter electrode, and a saturated calomel electrode was used as a reference electrode. The films were annealed in argon atmosphere. The influence of cold isostatic pressing before annealing on the microstructure and thermoelectric properties of the films was investigated. X-ray diffraction analysis indicates that the film grown on the indium tin oxide-coated glass substrate is pure rhombohedral Bi2Se3, and the film grown on the Ti substrate consists of both rhombohedral and orthorhombic Bi2Se3.展开更多
Magneto-optic Faraday rotation effect and the amount of bismuth substituted in yttrium iron garnet single crystal films prepared by gel-coating on modified gadolinium-gallium garnet substrates are investigated, where ...Magneto-optic Faraday rotation effect and the amount of bismuth substituted in yttrium iron garnet single crystal films prepared by gel-coating on modified gadolinium-gallium garnet substrates are investigated, where the gel is synthesized by a sol-gel reaction of nitrates and ethylene glycol. The coated gel is annealed in air at temperatures up to 660 ℃ for 4 h, which is about 300 ℃ lower than that of liquid-phase epitaxy. The maximum amount of Bi substitution is x =2.7 and the crystallization temperature of garnet phase decreases with the increase of x down to 520 ℃ for x =2.7. In this film, a huge Faraday rotation of -8.1×10 4 (°)/cm at λ =0.633 μm is obtained.展开更多
P-type Bi0.45Sb1.55Te3 thermoelectric material was synthesized using cold pressing process. The obtained sample was prepared in the form of pellet with a diameter of 10 mm and 2 mm thick and used as a target for laser...P-type Bi0.45Sb1.55Te3 thermoelectric material was synthesized using cold pressing process. The obtained sample was prepared in the form of pellet with a diameter of 10 mm and 2 mm thick and used as a target for laser ablation. The laser source was a pulsed CO2 laser working at a wavelength of 10.6 μm with a laser energy density of 2 J/cm2 per pulse. P-type Bi0.45Sb1.55Te3 thermoelectric thin films were deposited on Si substrates for different ablation times of 1, 2 and 3 h. The cross-section and surface morphologies of the thermoelectric films were investigated using field emission scanning electron microscopy (FE-SEM). The results show that the thickness and average particle size of the films increased from 35 to 58 nm, and 28 to 35 nm, respectively, when the ablation time was increased from 1 to 3 h. The crystalline structure of the TE films was investigated by X-ray diffraction (XRD).展开更多
A new basic electrolyte with two cationic plating additives, polydiaminourea and polyaminosulfone, was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil. Tell...A new basic electrolyte with two cationic plating additives, polydiaminourea and polyaminosulfone, was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil. Tellurium starts to deposit at a higher potential （-0.35 V） than bismuth （-0.5 V） in this electrolyte. The tellurium-to-bismuth ratio increases while the deposition potential declines from -1 to -1.25 V, indicating a kinetically quicker bismuth deposition at higher potentials. The as-deposited film features good adhesion to the substrate and smooth morphology, and has a nearly amorphous crystal structure disclosed by X-ray diffraction patterns.展开更多
Antimony-based bismuth-doped thin film, a new kind of super-resolution mask layer, is prepared by magnetron sputtering. The structures and optical constants of the thin films before and after annealing axe examined in...Antimony-based bismuth-doped thin film, a new kind of super-resolution mask layer, is prepared by magnetron sputtering. The structures and optical constants of the thin films before and after annealing axe examined in detail. The as-deposited film is mainly in an amorphous state. After annealing at 170- 370 ℃, it is converted to the rhombohedral-type of structure. The extent of crystallization increased with the annealing temperature. When the thin film is annealed, its refractive index decreased in the most visible region, whereas the extinction coefficient and reflectivity are markedly increased. The results indicate that the optical parameters of the film strongly depend on its microstructure and the bonding of the atoms.展开更多
基金Project(50401008) supported by the Chinese National Natural Science Foundation Project(2004CCA03200) supportedby the National Basic Research Program
文摘An automated thin-layer flow cell electrodeposition system was developed for growing Bi2Te3 thin film by ECALE. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. In the first attempt, this reductive Te underpotential deposition （UPD）/reductive Bi UPD cycle was performed to 100 layers. A better linearity of the stripping charge with the number of cycles has been shown and confirmed a layer-by-layer growth mode, which is consistent with an epitaxial growth. The 4∶3 stoichiometric ratio of Bi to Te suggests that the incomplete charge transfer in HTeO+2 reduction excludes the possibility of Bi2Te3 formation. X-ray photoelectron spectroscopy （XPS） analysis also reveals that the incomplete charge transfer in HTeO+2 occurs in Te direct deposition. The effective way of depositing Bi2Te3 on Pt consists in oxidative Te UPD and reductive Bi UPD. The thin film deposited by this procedure was characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and X-ray photoelectron spectroscopy（XPS）. A polycrystalline characteristic was confirmed by XRD. The 2∶3 stoichiometric ratio was confirmed by XPS. The SEM image indicates that the deposit looks like a series of buttons about （0.30.4 μm） in diameter, which is corresponding with calculated thickness of the epitaxial film. This suggests that the particle growth appears to be linear with the number of cycles, as it is consistent with a layer by layer growth mode.
文摘The thin film gas sensors of bismuth iron molybdate were prepared by ion beam sputtering technique. The prototype gas sensors studied have high sensitivity and selectivity to reducing gases, such as ethanol vapor, show a long term stability of response under most operating conditions and insensitivity to atmospheric humidity, and respond quickly comparing to traditional sintered gas sensors. The crystallographic structure and phase composition of these thin films were investigated with XRD, XPS and SEM techniques.
基金supported by the Major State Basic Research Development Program of China (No.2007CB607500.)
文摘Bi2Se3 thin films were electrochemically deposited on Ti and indium tin oxide-coated glass substrates, respectively, at room temperature, using Bi（NO3）3·5H2O and SeO2 as starting materials in diluted HNO3 solution. A conventional three-electrode cell was used with a platinum sheet as a counter electrode, and a saturated calomel electrode was used as a reference electrode. The films were annealed in argon atmosphere. The influence of cold isostatic pressing before annealing on the microstructure and thermoelectric properties of the films was investigated. X-ray diffraction analysis indicates that the film grown on the indium tin oxide-coated glass substrate is pure rhombohedral Bi2Se3, and the film grown on the Ti substrate consists of both rhombohedral and orthorhombic Bi2Se3.
文摘Magneto-optic Faraday rotation effect and the amount of bismuth substituted in yttrium iron garnet single crystal films prepared by gel-coating on modified gadolinium-gallium garnet substrates are investigated, where the gel is synthesized by a sol-gel reaction of nitrates and ethylene glycol. The coated gel is annealed in air at temperatures up to 660 ℃ for 4 h, which is about 300 ℃ lower than that of liquid-phase epitaxy. The maximum amount of Bi substitution is x =2.7 and the crystallization temperature of garnet phase decreases with the increase of x down to 520 ℃ for x =2.7. In this film, a huge Faraday rotation of -8.1×10 4 (°)/cm at λ =0.633 μm is obtained.
文摘P-type Bi0.45Sb1.55Te3 thermoelectric material was synthesized using cold pressing process. The obtained sample was prepared in the form of pellet with a diameter of 10 mm and 2 mm thick and used as a target for laser ablation. The laser source was a pulsed CO2 laser working at a wavelength of 10.6 μm with a laser energy density of 2 J/cm2 per pulse. P-type Bi0.45Sb1.55Te3 thermoelectric thin films were deposited on Si substrates for different ablation times of 1, 2 and 3 h. The cross-section and surface morphologies of the thermoelectric films were investigated using field emission scanning electron microscopy (FE-SEM). The results show that the thickness and average particle size of the films increased from 35 to 58 nm, and 28 to 35 nm, respectively, when the ablation time was increased from 1 to 3 h. The crystalline structure of the TE films was investigated by X-ray diffraction (XRD).
基金supported by the National Natural Science Foundation of China(No.50731006)
文摘A new basic electrolyte with two cationic plating additives, polydiaminourea and polyaminosulfone, was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil. Tellurium starts to deposit at a higher potential （-0.35 V） than bismuth （-0.5 V） in this electrolyte. The tellurium-to-bismuth ratio increases while the deposition potential declines from -1 to -1.25 V, indicating a kinetically quicker bismuth deposition at higher potentials. The as-deposited film features good adhesion to the substrate and smooth morphology, and has a nearly amorphous crystal structure disclosed by X-ray diffraction patterns.
基金supported by the National Basic Research Program of China (No. 2007CB935402)the National Natural Science Foundation of China(Nos. 50872139 and 60644002)
文摘Antimony-based bismuth-doped thin film, a new kind of super-resolution mask layer, is prepared by magnetron sputtering. The structures and optical constants of the thin films before and after annealing axe examined in detail. The as-deposited film is mainly in an amorphous state. After annealing at 170- 370 ℃, it is converted to the rhombohedral-type of structure. The extent of crystallization increased with the annealing temperature. When the thin film is annealed, its refractive index decreased in the most visible region, whereas the extinction coefficient and reflectivity are markedly increased. The results indicate that the optical parameters of the film strongly depend on its microstructure and the bonding of the atoms.
