Nano Hybrids Vol. 4

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Authors: Kanchan Ulman, Mighfar Imam, Shobhana Narasimhan, Anders Odell, Anna Delin
Abstract: The photoswitching molecule dithienylethene (DTE) is an interesting candidate for constructing optoelectronic molecular devices since it can be made to switch between a closed and an open conformation using light. We here report computations, based on density functional theory (DFT) and the non-equilibrium Green function (NEGF) method, of the spin-resolved conductance of the two DTE isomers attached to spin-polarized nickel leads. Results are compared and contrasted to those of other contact materials (nonmagnetic Ni, Ag, and Au), analyzing the physical origins of the various features in the transmission function. It was found rather surprisingly, that the two spin channels in the Ni/DTE/Ni device have almost identical I-V characteristics, despite one channel being d-dominated and the other one s-dominated. It was also observed that the Ni-based device exhibits a sustained high conductance ratio also for high bias - a property that may be of relevance in future device design. Furthermore, two computational schemes for calculating the conductance were compared and analyzed. It was found that even for very small bias the molecular orbital polarization was decisive for spin-related properties such as the spin current ratio and magneto-resistance in the Ni/DTE/Ni device.
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Authors: Mehdi Qasim, Jinan B. Al-Dabbagh, Ahmed N. Abdalla, M.M. Yusoff, Gurumurthy Hegde
Abstract: Optimum thermal annealing process operating condition for nanostructured porous silicon (nPSi) by using radial basis function neural network (RBFNN) was proposed. The nanostructured porous silicon (nPSi) layer samples prepared by electrochemical etching process (EC) of p-type silicon wafers under different operatingconditions, such as varyingetchingtime (Et), annealing temperature (AT), and annealing time (At). The electrical properties of nPSi show an enhancement with thermal treatment.Simulation result shows that the proposed model can be used in the experimental results in this operating condition with acceptable small error. This model can be used in nanotechnology based photonic devices and gas sensors.
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Authors: Farhad Larki, Arash Dehzangi, Jumiah Hassan, Alam Abedini, E.B. Saion, Sabar D. Hutagalung, A. Makarimi Abdullah, M.N. Hamidon
Abstract: The spark of aggressive scaling of transistors was started after the Moors law on prediction of device dimensions. Recently, among the several types of transistors, junctionless transistors were considered as one of the promising alternative for new generation of nanotransistors. In this work, we investigate the pinch-off effect in double gate and single gate junctionless lateral gate transistors. The transistors are fabricated on lightly doped (1015) p-type Silicon-on-insulator wafer by using an atomic force microscopy nanolithography technique. The transistors are normally on state devices and working in depletion mode. The behavior of the devices confirms the normal behavior of the junctionless transistors. The pinch-off effect appears at VG +2.0 V and VG +2.5 V for fabricated double gate and single structure, respectively. On state current is in the order of 10-9 (A) for both structures due to low doping concentration. The single gate and double gate devices exhibit an Ion/Ioff of approximately 105 and 106, respectively.
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Authors: Nurul Sabihah Zakaria, Rabizah Makhsin Siti, Azlan Abdul Aziz, Khairunisak Abdul Razak
Abstract: Colloidal gold or also known as gold nanoparticle (AuNP) is a suspension of sub-nanometer-sized particle of gold in a fluid usually water. The synthesized AuNP have particle sizes ranging from, e.g. 10 nm to 100 nm with color changing from an intense red color (for particle less than 100 nm) to a dirty yellowish color (for larger particle). The size of AuNP determines their unique optic, electronic and magnetic properties. AuNP nowadays has widely used in material science [ and biomedical [2,. For many of this application, the AuNP need to be monodispersed and have a specific size. Generally, colloidal AuNP can be synthesis as monodispersed nanoparticles with core sizes ranging from 1nm to 250nm. The synthesis of AuNP can be controlled in different size and shapes due to their ability to react and agglomerate with other nanoparticles in their ambient condition [. Furthermore, AuNP can also becomes more prone to flocculation and aggregation [. As the size of colloidal AuNP increase so do their sensitivity to salt and environment. AuNP have increasingly gain interest due to their unique properties ofcontrolable morphology [ and size dispersion [6,, less toxicity and ease in synthesis and detection.
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Authors: Mohd Farhan Khan, Akhter H. Ansari, M. Hameedullah, M.B. Lohani, Mohammad Mezbaul Alam, Zeid A. Al Othman, Abu Mustafa Khan, Mohd Kamran Khan
Abstract: Since few decades, the fabrications of metal oxide nanoparticles (MO-Nps) as well as their uses in various segments have been increased manifolds. An easy effort to produce an important category of MO-Nps as Zinc oxide nanoparticles (ZnO-Nps), with the assistance of mechano-solution method at various low temperatures, introducing Zinc acetate dihydrate and Sodium hydroxide into the molar solution of C19H42NBr complex (Cetrimonium bromide, CTAB) for much less than an hour was projected. The impact of this method performed at two different ranges of process temperatures was studied and the magnitude of the ZnO-Nps (like particle size, morphology and L/D dimensions) has been reported. On the top of this, the morphological study of these Nps has been presented. The characterization of the synthesized Nps was carried out with the help of SEM with EDS, XRD, UV-Vis spectroscopy. The scanning electron microscopy has revealed the synthesis of peanut-shaped ZnO nanobunches (NBs) at two different ranges of temperature. An overall viable growth of the solitary nanoparticles constituting of ZnO-NBs has also been put forth. Hence, the effect of temperature on C19H42NBr complex (stabilizer) has been reported. In addition, a postulated model depicting the relationship of the temperature effect on the process parameters of ZnO-NBs has also been floated. The Gram +ve bacteria, Bacillus subtilis is a rod shaped bacteria which is commonly known as normal gut commensal in humans. Due to the emergence of anti-biotic resistant drugs, alternate medications are under primary considerations. A noteworthy experimentation was concerned with anti-bacterial activity of therapeutically viable Gram +ve bacteria, Bacillus subtilis and it was found that reported ZnO-NBs have become the promising entities for terminating the growth of these bacterias.
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Authors: Haroon Haiza, A. Azizan, Aizat Hazwan Mohidin, D.S.C. Halin
Abstract: In this work, silver nanoparticles have been successfully prepared with a simple, cost-effective and reproducible aqueous room temperature green synthesis method. Honey was chosen as the eco-friendly reducing and stabilizing agent replacing most reported reducing agents such as hydrazine, sodium borohydride (NaBH4) and dimethyl formamide (DMF) which are highly reactive chemicals but also pose a biological risk to the society and environment. The size and shape of silver nanoparticles were modulated by varying the honey concentration and pH of the aqueous solution that contain silver nitrate as the silver precursor, sodium hydroxide as the pH regulator and ethylene glycol as the solvent. The silver nanoparticles obtained are characterized by field-emission scanning electron microscope (FESEM), ultraviolet-visible spectra (UV-Vis) and Fourier transform infrared spectroscopy (FTIR). From SEM analysis, it was found that by increasing the concentration of honey, the size of silver nanoparticles produced decreased, from the range of 18.98 nm - 26.05 nm for 10 g of honey to 15.63 nm - 17.86 nm for 40 g of honey. Similarly, the particle size decreased as the pH of the aqueous solution increased. UV-Vis spectra revealed large anisotropic and polydispersed Ag nanoparticle were produced.
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Authors: Sonali Saha, M.M. Malik, M.S. Qureshi
Abstract: In this work, a green route for synthesis of Ag nanoparticles is presensted. For the synthesis of Ag nanoparticles, tulasi leaf extract (Ocimum leaf) in combination with microwave irradiation was used which yielded stable spherical Ag nanoparticle in the range of 5-50 nm. Surface morphology of nanoparticle was analyzed by XRD and TEM. UV-Vis analysis was also carried out to characterize the synthesized nanoparticles. The main feature of the process is that it is carried out in a very short span of time in comparison to other conventional physical, chemical and biological methods. Microwave assisted synthesis suppresses the enzymatic action to keep the process easy, fast and eco-friendly.
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