Results 1 - 10 of 317
Results 1 - 10 of 317. Search took: 0.02 seconds
|Sort by: date | relevance|
[en] A type of voltage controlled phase shifter developed by the laboratory is better than mechanical phase shifter in all respects of performance, price, and reliability. Its principle is based on vector composition so this new phase shifter is called vector-combining voltage controlled phase shifter. The new phase shifter has been applied in HIRFL phase stabilization system and satisfactory result has been obtained
[en] The HIRFL accelerator system uses a buncher to produce the required bunched beam at the injector SFC entrance. The buncher is located immediately upstream of the SFC in the injection beam line. The single gap buncher consists of two parallel mesh plates. The buncher is excited by a RF voltage with sawtooth-like wave form
[en] Aluminum and fluorine co-doped zinc oxide (AFZO) thin films were prepared in Ar + H_2 atmospheres by rf magnetron sputtering at room temperature. The structural, electrical, and optical properties of the prepared films were investigated using X-ray diffraction, scanning electron microscopy, atomic force microscopy, Hall-effect measurement, X-ray photoelectron spectroscopy, and ultraviolet–visible spectrometry, and their dependence on deposition atmosphere (i.e. H_2 / (H_2 + Ar) ratio) was studied. The resulting films showed a (0 0 2) diffraction peak, indicating a typical wurtzite structure, and the optimal film crystallinity was obtained with the H_2 / (H_2 + Ar) ratio of 3%. The electrical resistivity of AFZO films decreased to 9.16 × 10"−"4 Ω-cm, which was lower than ZnO:Al and ZnO:F films due to double doping effect of Al and F. The resistivity further decreased to below 5 × 10"−"4 Ω-cm for the AFZO film with the H_2 / (H_2 + Ar) ratio of 3%–5%. All the films regardless of hydrogen content displayed high transmittances (> 92%) in the visible wavelength range. Applying the developed AFZO films as front transparent electrodes, amorphous Si thin film solar cells were fabricated and the open-circuit voltage, fill factor, and efficiency of the cell with the hydrogenated AFZO film were improved in contrast to those without the hydrogenated film. - Highlights: • H_2 doping improves optoelectronic properties of Al, F co-doped ZnO (AFZO) films. • Resistivity of AFZO films decreases to 4.4 × 10"−"4 Ω-cm with the 3% H_2/(Ar + H_2) ratio. • AFZO films show high average visible transmittances of above 92%. • Efficiency of a-Si thin film solar cells is improved by AFZO:H as front electrode.
[en] FePt and FePt/C thin films were prepared by RF magnetron sputtering, then post-annealed in vacuum. The as-deposited films were in disordered state, and the ordered L10 structure was obtained by post-annealing at 550 deg. C for 30 min. Superlattice peaks (0 0 1) and (1 1 0) can be found in the X-ray diffraction pattern of FePt and FePt/C films, which indicate that the FCC phase has been partially transformed into L10 phase. As the thickness of C layer increased from 1 to 3 nm, the coercivities of the FePt/C multilayer decreased from 6.3 to 1.8 kOe, which indicated that thicker carbon layers in the sample would produce a higher activation energy barrier for the disorder-order transformation. With increasing the C concentration, the grain size and intergrain interactions of FePt/C multilayer films were decreased
[en] Highlights: • Al and F co-doped ZnO (AFZO) thin films were prepared by rf magnetron sputtering. • Effects of substrate temperature on properties of AFZO films were investigated. • The AFZO films show a typical hexagonal wurtzite structure and are (0 0 2) oriented. • The AFZO thin film prepared at 200 °C exhibits a low resistivity of 2.88 × 10"−"4 Ω-cm. • The average visible transmittances of all the AFZO thin films exceed 92%. - Abstract: ZnO is a wide bandgap semiconductor that has many potential applications such as solar cells, thin film transistors, light emitting diodes, and gas/biological sensors. In this study, a composite ceramic ZnO target containing 1 wt% Al_2O_3 and 1.5 wt% ZnF_2 was prepared and used to deposit transparent conducting Al and F co-doped zinc oxide (AFZO) thin films on glass substrates by radio frequency magnetron sputtering. The effect of substrate temperatures ranging from room temperature (RT) to 200 °C on structural, morphological, electrical, chemical, and optical properties of the deposited thin films were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Hall effect measurement, X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and UV–vis spectrophotometer. The XRD results showed that all the AFZO thin films had a (0 0 2) diffraction peak, indicating a typical wurtzite structure with a preferential orientation of the c-axis perpendicular to the substrate. The FE-SEM and AFM analyses indicated that the crystallinity and grain size of the films were enhanced while the surface roughness decreased as the substrate temperature increased. Results of Hall effect measurement showed that Al and F co-doping decreased the resistivity more effectively than single-doping (either Al or F doping) in ZnO thin films. The resistivity of the AFZO thin films decreased from 5.48 × 10"−"4 to 2.88 × 10"−"4 Ω-cm as the substrate temperature increased from RT to 200 °C due to the increased carrier concentration and Hall mobility. The optical transmittances of all the AFZO thin films were over 92% in the wavelength range of 400–800 nm regardless of substrate temperature. The blue-shift of absorption edge accompanied the rise of the optical band gap, which conformed to the Burstein-Moss effect. The developed AFZO thin films are suitable as transparent conducting electrodes for various optoelectronic applications.
[en] The quality of sputtered-deposited SmCo/Cr films used for high-density magnetic recording media depends on several sputtering factors of the SmCo magnetic layer. The investigation into the optimal sputtering conditions needs a large number of experiments. The orthogonal design of experiments and the analysis of variance are considered effective methods, which not only minimize the number of experiments but also optimize the sputtering condition of the SmCo layer for high coercivity of SmCo/Cr films. Using the orthogonal design of experiments, the effects of four factors, such as target-substrate distance, DC power, sputtering pressure and sputtering time, were simultaneously investigated by only nine experiments. It is found that target-substrate distance, DC power and the sputtering pressure are very important factors for coercivity, while the effect of sputtering time is not obvious. In addition, the optimal condition of the SmCo layer was obtained. It can be proved that the results of our experiment are at the 95% level