A study on defect controlled morphology of Organic/Inorganic composite nanofibers with different heat flow rates

One dimensional nanofibers of organic and inorganic materials have been used in filters, optoelectronic devices, sensors etc. It is difficult to obtain ultra fine fibers of inorganic materials having lengths in the order of millimeter as they tend to break during formation due to thermal and other mechanical stresses. In this study, we have investigated the mechanism to prevent the defect formation and the breaking ZnO nanofibers by using optimized heat flow rates. ZnO nanofibers were obtained by heat treating the PVA composites fibers formed by electrospinning. The morphology and structural characteristic of prepared samples were investigated by Scanning electron microscopy and X-ray diffraction. It was found that the morphology of the composite and annealed nanofibers could be influenced by the concentration of the polymer content and heat flow rate during thermal treatment respectively. A lower concentration favors the formation of defects along the fiber and the number of defects reduces when the concentration is increased. The reasons for the formation of defects and their reduction, and the observed structural changes of ZnO nanofibers during heat treatment are also discussed.     

First-principles study of electron transport in azulene molecular junction: effect of electrode material on electrical rectification behavior

The feasibility of using an azulene molecule as a molecular rectifier with different electrode materials, viz. gold (Au), silver (Ag), and copper (Cu), was investigated using density functional theory (DFT) and the nonequilibrium Green’s function (NEGF) method. It was found that the azulene-like molecule exhibited high conductance and bias-dependent rectification effect. The dipole moment was increased due to the charge effect in the azulene molecular junction, based on charge transfer from the seven- to five-membered ring, giving the system stability and forming a dipole. It was also observed that the azulene–Au molecular junction showed higher rectification ratio than those with Ag or Cu, due to high coupling strength between the molecule and electrodes. Thus, Au electrodes are suggested as a good potential candidate for use in azulene-based highly conductive unimolecular rectifiers operating in lower bias region.     

Spin-dependent electron transport analysis of benzyl alcohol and p-cresol based single molecular junction: a DFT-NEGF approach

Journal of Materials Science: Materials in Electronics - A single molecular junction can act as spintronic device when a molecule coupled with magnetic electrodes. Various analyses have been done...     

In-situ preparation of high optical quality ZnO nanoparticles in nanofibrous PVA matrix

Fabrication of ultraviolet light emitting devices using ZnO nanostructures is still difficult due to the high cost synthesis for high quality ZnO. It is important to suppress the visible emission. In this paper, we report the effective low cost in-situ preparation of high quality monodispersed and non-agglomerate ZnO nanoparticles in nanofibrous PVA matrix derived from electrospinning method. The final product was investigated by SEM, EDAX, XRD, FTIR, TEM, and SAED. The XRD analysis proved the successful preparation of ZnO with wurtzite hexagonal phase. FTIR spectroscopic measurements showed the interaction between ZnO and PVA. The purity of the sample was studied using PL. The result showed that the obtained sample exhibits intense ultraviolet emissions at 369 nm while the absence of deep level emission confirms the high quality sample. PVA matrix and electrospinning method are found to have a vital role to the preparation of defect free ZnO. Experimental results have proven that the prepared ZnO by this method have excellent optical quality.     

10 nm TriGate High k Underlap FinFETs: Scaling Effects and Analog Performance

Nano scale devices with improved performance than the conventional CMOS devices is of great need in recent days. The paper investigates the performance of