Papers by Keyword: Semiconductor

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Authors: Jing Wen, Chun Ying Zuo, Cheng Zhong
Abstract: Motivated by the widely discussed Ag doped ZnO and the lack of follow-up reports about the realization of p-n junctions, we calculated the electronic structures and optical properties of pure, Ag-doped and Ag-F codoped ZnO based on the density-functional theory. It was found that Ag doped ZnO shows p-type conduction character. But there are some unstable factors and self-compensations in this structure. We also calcualted the formation energy and ionization energy of the impurity for Ag-F codoped ZnO. It was found that incorporating the reactive donor F into Ag doped ZnO system, not only enhances the Ag acceptor solubility, but also gets a shallower Ag acceptor energy level in the band gap. In addition, we analyze the imaginary part of the dielectric function, reflectivity and absorption coefficient for pure ZnO and Ag-F codoped ZnO. Compared with the pure ZnO, the remarkable feature for Ag-F codoped ZnO is that there is a strong absorption in the visible-light region, which indicates that it could be taken as a potential candidate for a photocatalytic material.
Authors: Chao Xu, Dong Chen
Abstract: The structural and elastic properties of the cubic spinel Ge3N4 semiconductor have been investigated using the ab initio scheme within the generalized gradient approximation in the framework of density functional theory. Quantities such as lattice constants and elastic constants of interest are calculated. A good agreement is found between our results and the other data. Through the lattice dynamics, in which the finite displacement method is used, we have obtained successfully the thermal properties such as the phonon curve, free energy, heat capacity and Debye temperature in the whole temperature range from 0 to 1000K. It is the authors ambition that these results will inspire further experimental study on the Ge-based semiconductors. * Corresponding author: CHEN Dong
Authors: Filiz Karaomerlioglu, Sevket Simsek, Amirullah M. Mamedov, Ekmel Ozbay
Abstract: Photonic crystals (PCs) have many applications in order to control light-wave propagation. A novel type of two-dimensional anisotropic PC is investigated band gap and optical properties as a hollow semiconductor nanorod with nematicliquid crystals (LC). The PC structure composed of an anisotropic nematicLC in semiconductor square hollow nanorod is designed using the plane wave expansion (PWE) method and finite-difference time-domain (FDTD) method. It has been used 5CB (4-pentyl-4`-cyanobiphenyl) as LC core, and Tellurium (Te) as square hollow nanorod material.The PC with hollow Tenanorod with nematicLC is compared with the PC with solid Tenanorodand the PC with hollow Tenanorod.
Authors: E. Nxusani, P.M. Ndangili, R.A. Olowu, A. N. Jijana, T. Waryo, N. Jahed, R.F. Ajayi, Priscilla Gloria Lorraine Baker, Emmanuel Iheanyechukwu Iwuoha
Abstract: Water soluble and biocompatible 3-mercaptopropionic acid capped gallium selenide nanocrystals, were synthesized from hydrated gallium (III) perchlorate and selenide ions. The 3-mercaptopropionic acid capped gallium selenide nanocrystals, was non-fluorescent but showed a sharp UV-vis absorption maximum at 250 nm.The synthesized nanoparticle was used to develop an electrochemical biosensor for the detection of 17-alpha-ethinyl estradiol, an estrogenic endocrine disrupting compound (e-EDC). The biosensor was fabricated by potentiostatic deposition of novel gallium selenide nanocrystals on a L-cystine modified gold electrode, followed by covalent coupling of genetically engineered cytochrome P450-3A4 (CYP3A4), a Heme containing enzyme. The biosensor gave an electrochemical response at about-220 mV. The results revealed that 3-Mecarptopropanoic acid capped Gallium Selenide nanocrystals can be used in conjunction with CYP3A4 as an electrode modifier for the detection of 17-alpha ethinyl estradiol. The 3-Mecarptopropanoic acid capped Gallium Selenide nanoparticles exhibited a semiconductor like behaviour.
Authors: P.S. Pa
Abstract: A bluge rotational tool has been developed as an effective precision electrochemical removal for the thin film nanostructures from LCD panels. This ultra-precise process effectively removes defective Indium-Tin-Oxide layers allowing LCD panels to be returned to the production line and significantly reduces costs. In the current experiment a 7th Generation TFT-LCD panel was used. A high rotational speed of the cheek rotational tool elevates discharge mobility and improves the removal effect. A negative electrode of large diameter with a small end radius provides higher current density and also improves the removal affect. Pulsed direct current can improve the effect of dregs discharge and is advantageous when combined with a higher electric power. A fast feed combined with a high current flow results in very effective removal of the color filter layer. This novel design using electrochemical removal as a precision recycling process for removing ITO layers from LCD panels is clean, effective and very fast.
Authors: Tossapol Tippo, Chanchana Thanachayanont, Hideki Nakajima, Prayoon Songsiriritthigul, Micheal Hietschold, Apinunt Thanachayanont
Abstract: This study demonstrates an attempt to fabricate the 25 µm channel-length bottom-contact pentacene TFTs using thermal evaporation through shadow mask technique and to investigate crystal structure, morphology and electronic structure of the pentacene layer deposited at the same time on gold (Au) source-drain electrodes and Poly(methyl methacrylate) (PMMA) gate-dielectric of the TFTs. The pentacene layers with thicknesses of 50 nm were deposited at the evaporation rates of 0.1, 0.5, 1.0 and 1.5 nm/min at substrate temperatures of 60 °C. These conditions were employed with and without preheating at 80 °C before deposition. Preheating at 80 °C was found to improve quality of the pentacene film on the PMMA gate-dielectric. Using the deposition rate of 1 nm/min and the substrate temperature of 60 °C, best performance of TFTs were obtained. At this deposition condition, pentacene film work function was found to be higher on the Au source-drain electrodes than on the PMMA gate-dielectric.
Authors: Xian Ping Fu, Sheng Long Liao
Abstract: As the electronic industry advances rapidly toward automatic manufacturing smaller, faster, and cheaper products, computer vision play more important role in IC packaging technology than before. One of the important tasks of computer vision is finding target position through similarity matching. Similarity matching requires distance computation of feature vectors for each target image. In this paper we propose a projection transform of wavelet coefficient based multi resolution data-structure algorithm for faster template matching, a position sequence of local sharp variation points in such signals is recorded as features. The proposed approach reduces the number of computation by around 70% over multi resolution data structure algorithm. We use the proposed approach to match similarity between wavelet parameters histograms for image matching. It is noticeable that the proposed fast algorithm provides not only the same retrieval results as the exhaustive search, but also a faster searching ability than existing fast algorithms. The proposed approach can be easily combined with existing algorithms for further performance enhancement.
Authors: Hiroyuki Kawanishi, Yoshinori Hayafuji
Abstract: It is known that acceptor-carbon complexes have ionization energies less than those of the corresponding substitutional, separate acceptors in silicon. We present the formation mechanism for a shallower acceptor energy level called an X level that is due to an indium- carbon pair. Ab initio calculation methods were used to evaluate electronic structures and lattice relaxations of silicon with indium, carbon or a carbon-indium dimer. The results shows that the bonding interaction between the 5p orbitals of the indium atom and the 3sp orbitals of the silicon atoms bound with the indium atom mainly determines the ionization energy of the X level, and the ionic bonding interaction of the carbon atomic orbitals with the indium atomic orbitals in the X level enables the bonding interaction of the orbitals between the indium atom and the silicon atom to lower the corresponding indium acceptor level, and then to form the shallower X level.
Authors: Jian Guo Mao, Hui Yu Zhang, Guang Min Lu, Jian Kang Xu
Abstract: This template explains a design of a fuzzy temperature control system for the pressure-sensitive paint. According to the relationship between temperature difference and the current of semiconductor chip, the fuzzy system control theory, control the volume of the domain, control rules design, and design a constant current source circuit to control the current through the chip, and finally make experimental verification of the system. The system hardware uses C8051F040 MCU, temperature chip DS18B20, keyboard chip CH451.
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