Papers by Keyword: Doping

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Authors: Vladislav R. Baraz, S.S. Gerasimov, I.A. Gruzdeva
Abstract: The article is devoted to the study of Cu-Ni-Zn ternary alloy properties. German silver is applied in the instrument making industry, shipbuilding industry, and medical tool production. Furthermore, German silver is extensively used for domestic goods and costume jewelry. It is known that the aluminum and tin additions improve the Cu-Ni-Zn alloy flowing and casting mold fillability. It is a matter for the figurine and thin section casting production. That is why, using the experiment planning method we have studied the effect of Al and Sn alloyage and crystallization temperature on structure, casting characteristics and the casting characteristics of German silver. The study was realized by casting samples which were produced with lost wax method. Aluminum microadditives (0.4 %) have a positive impact on the casting mold fillability and improve markedly surface quality of casting samples. Tin leading into melt (about 4 %) ensure the marked growth of yield strength (by 65...70 %), while the elongation is maintained. The role of the mold temperature has a lesser impact on the yield strength. The mold temperature reduction from 550 °C to 450 °C leads to the grain size decrease and the little yield strength increase. Moreover, the surface condition measurement shows that aluminum and tin additions greatly reduce the castings surface roughness.
Authors: C.Q. Huang, X.B. Liu, X.A. Mei, J. Liu
Abstract: The electrical properties of Er2O3-doped bismuth titanate,Bi4-xErxTi3O12 (BET) ceramics prepared by a conventional electroceramic technique were investigated. XRD analyses revealed Bi-layered perovskite structure in all samples. SEM micrographs showed randomly oriented and plate-like morphology. For the samples with x=0.4 and 1.0 the current-voltage characteristics exhibited negative differential resistance behaviors and their P-E hysteresis loops were characterized by large leakage current, whereas for the samples with x=0.6 and 0.8 the current-voltage characteristics showed simple ohmic behaviors and their P-E hysteresis loops were the saturated and undistorted hysteresis loops. The remanent polarization ( Pr ) and coercive field (Ec) of the BET ceramic with x=0.8 were above 20μC/cm2 and 65KV/cm , respectively.
Authors: B. Hahn, M. Wörz, G. Heindel, E. Pschorr-Schoberer, W. Gebhardt
Authors: M.M. De Souza, Srinivasan Chakravarthi, Amitabh Jain
Abstract: Heavy species such as Sb, In, and Ge are required to meet the challenges of future dopant engineering in planar CMOS technology. An understanding of the interactions of these species with each other and with conventional dopants is urgently required in order to meet aggressive criteria for junction control in sub-sixty nanometer technology nodes. In the current work, the interactions between Sb and In have been explored as a function of ion implantation dose and annealing treatment. The data shows strong interaction between the two species which prevents the dissolution of an as-implanted In profile even after high temperature anneal. The nature of the interaction is probed with fundamental calculations using plane wave density functional theory. A strong binding for an Sb-In-vacancy complex is revealed. Band structure analysis indicates that this defect complex introduces several unoccupied states primarily in the upper half of the bandgap. The two species contribute with nearly equal magnitude to the top valence band.
Authors: P. Jantaratana, Pisutti Dararutana, Wiwat Wongkokua, Sorapong Pongkrapan, P. Wathanakul
Abstract: The dielectric constant values of a set of synthetic alpha alumina samples doped with Cr and Be were determined using parallel plate method. The voltage frequency was selected at 1 MHz. When Cr was doped to the sample, the dielectric constant was increased due to the increase in polarizations of the sample, whereas the Be-doped one showed the decrease in dielectric constant cf. the undoped synthetic alpha alumina (reference sample). Experiments on doping alpha alumina with both elements showed increasing in dielectric constant compared to the undoped reference sample, i.e., Cr has more influence to the dielectric constant value. Dielectric constants of a set of natural sapphires were also measured and compared to those obtained from the synthetic ones. The results of both natural and synthetic samples varied in the same direction. It suggests, however, that the geological origins of the samples are needed to be considered. This is due to the differences in physico-chemical conditions of their formations that would have influenced partitioning of trace elements as well as evolving of defects in natural samples. Increasing of the R1 and R2 photoluminescence wavelengths and decreasing of refractive indices of the doped samples cf. those of the reference sample were obtained from the experiments.
Authors: Harun Özkişi, Seyfettin Dalgıç
Abstract: Recently, it has become indispensable to use semiconducting nanostructures in the production and development of electronic devices. In this study, the bulk and nanowire heterostructures of the BP / GaN system have been investigated for the structures pure and Te atom doped. In calculations, the plane wave self-consistent field program based on density functional theory was used. The average potentials of the aforementioned systems have been calculated and the interface effect has investigated.
Authors: Ni Ni Yuan, Hong Cun Bai, Yu Hua Wu, Jun Li, Yong Qiang Ji
Abstract: The hybrid nanostructures made of single-walled carbon nanotubes substitutionally doped with silicon atoms were investigated by quantum chemistry calculations based on density functional theory in this paper. The zigzag (12, 0) tube was considered to construct the Si-doped tubes. The geometrical structures, relative stabilities and electronic properties of the doped tubes were studied in details and compared with those of the pristine nanotubes. It is found that the Si-doped nanotubes exhibit lower thermodynamic stability than those of the undoped tubes from viewpoint of cohesive energy. The energy levels of the frontier orbitals vary very little when the silicon atom is introduced into the nanotubes. However, most doped tubes present larger Eg than those of the pristine ones.
Authors: Satoshi Murata, Yoshihiro Nakamura, Tomohiko Maeda, Yoko Shibata, Mina Ikuta, Masaaki Sugiura, Shugo Nitta, Motoaki Iwaya, Satoshi Kamiyama, Hiroshi Amano, Isamu Akasaki, Masahiro Yoshimoto, Tomoaki Furusho, Hiroyuki Kinoshita
Abstract: The dependence of donor-acceptor pair (DAP) emission properties on impurity concentrations of N and B in 6H-SiC epilayers was investigated. Doped samples were grown by closed sublimation technique, and impurity concentrations were confirmed by secondary ion mass spectrometry (SIMS). Photoluminescence (PL) measurement results indicate that p-type 6H-SiC with NA>ND had extremely low DAP emission efficiency, whereas n-type 6H-SiC with NA
Authors: Rahul Radhakrishnan, Tony Witt, Seungchul Lee, Richard Woodin
Abstract: Optimized design of Silicon Carbide (SiC) power devices depends, besides power device physics, also on consideration of basic properties and technological readiness of the material. This paper presents a novel analysis of the dependence of variation of epitaxial doping and thickness on the determination of the optimum design point of SiC devices. We introduce electric field at epitaxy-substrate interface as a useful parameter in controlling the dependence of device parameters on epitaxy. Using this method as criterion for design can improve the robustness of SiC devices to epitaxial variation and hence the process yield.
Authors: Zhi Gang Wang, Wen Cheng Gao, Jing Li, Ke Gao Liu
Abstract: SnS thin film, a potential earth-abundant photovoltaic material, has particularly generated interest because of its nontoxic nature, the band gap of it matches well with solar spectrum and its high absorption coefficient. It provides a brief description of the development of SnS thin film for solar cells, and surveys several preparation methods of SnS thin film, then introduces the crystal structure of SnS. The effects of different doping elements and concentrations for SnS thin film on performance were outlined, and the development and the structure of solar cells based on SnS thin films were discussed. Finally, the development tendency and prospects were predicted.
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