Does Supervisory Behavior and Support Lead to Teacher’s Affective Commitment?

To meet the demand of globalization war of diversity talent and fast technological developments in order to deploy and preserve an innovative workforce specifically in education industry should allow a greater amount of flexibility and innovation in their HRM policies and practices Furthermore Indian universities are presently grappling with the shortage of teachers Therefore it is imperative for universities to retain develop and improve the performance of their existing educators The central role Human Resource Management HRM practices play in creating and maintaining employee s affective commitment is critical especially in a highly socially interactive job of teaching HRM is seen as a mechanism that nurtures social relationships in order to support an innovative workforce and enlarge the innovation capacity of organization

Novel ZnO nanostructures over gold and silver nanoparticle assemblies

We report the growth of well-oriented nest (reticulum)-like and lotus flower-like submicron structures of ZnO, over gold and silver nanoparticle assemblies, respectively. The structures were grown by a convenient chemical bath deposition method in a nutrient solution made of zinc nitrate (Zn(NO3)2 · 6H2O) and methyl amine (CH3NH2) at low temperature. SEM, XRD, Raman, UV-Vis and fluorescence spectra were used to study the morphology, crystallinity and phase purity of the structures. The ZnO submicron structures were found to be in the hexagonal wurtzite phase

Reduced Graphene-Oxide Transducers for Biosensing Applications Beyond the Debye-Screening Limit

In the field of label-free biosensing, various transducer materials and strategies are under investigation to overcome the Debye-screening limitation of charged biomolecules. We demonstrate an in-line, impedimetric aptasensor with reduced graphene-oxide (rGO) thin films as transducers to detect prostate specific antigens (PSA) in a physiological buffer solution. Unlike classical electrochemical impedance spectroscopy (EIS), this direct, label-free and fully-electronic biosensor approach does not need any redox markers. As specific capture molecules, short anti-PSA aptamers ensured a close binding of the target molecules to the transducer surfaces. Results showed a limit of detection smaller than 33 pM of PSA and a wide detection range from 0.033 to 330 nM fully covering the clinically relevant range of PSA (0.115–0.290 nM). This promising performance can be attributed to the bipolar electronic transport characteristics of the ultra-thin rGO layers similar to pristine graphene. The attachment of target biomolecules to the films changes the resistance of the rGO thin films. Such an in-line EIS configuration with rGO thin films opens promising prospects for biosensing beyond the Debye-screening limitation, which is a major challenge for conventional semiconductor field-effect devices towards clinical applications.</p

Self-Assembled Liquid-Gated Zinc Oxide Nanowire Transistors:Fabrication and Sensing Operation

This thesis aims at the site-specific realization of self-assembled field-effect transistors (FETs) based on semiconducting Zinc oxide NWs and their application towards chemical and bio-sensing in liquid medium. At first, a solution based growth method for hierarchical ZnO nanostructures was devised in order to achieve synthesis of high quality ZnO NWs. This solution based growth method was then deployed for the growth of NWs from preferred sites on a substrate. In order to make a transistor, microelectrode pairs prewritten on a Si/SiO2 chip (4mm◊4mm) using standard photolithography procedure served as growth sites and also formed source and drain terminals. The NWs bridging these "source" and "drain" electrodes formed the transistor channel. The procedure here yields ZnO NWs in up to 100 percent of the positions available for growth. The site-specific self-assembled fabrication of ZnO NW FETs was evaluated in terms of scalability and applications. The procedure was extended from 4mm◊4mm silicon chips to large area silicon wafers (80mm◊80mm) and flexible substrates of Kapton polyimide of the same size. On the large area substrates this procedure yields ZnO NWs in up to 80 percent of the positions available for growth, which can be bettered. Furthermore, the method was also employed to fabricate ZnO NW FETs in situ in a microfluidic channel. For this purpose the precursor solution was let to flow on to the microelectrode pairs with the help of microfluidic channels assembled on top of the substrate. The substrate was heated locally under the microelectrode pairs to stimulate the NW growth. Thus a solution-based self-assembled fabrication of NW FETs was achieved locally inside a microfluidic channel. Microfluidic channels were made of silicon nitride (Si3N4) on top of Si/SiO2 chips and facilitated the characterization of FETs in liquid medium. Alternatively, microfluidic channels made of polydimethylsiloxane (PDMS) were used for characterization of transistor devices in liquids. In order to deploy FETs in liquids, the back-gate is replaced by a reference electrode (Ag/AgCl) and the potential is applied through a liquid surrounding the transistor channel (ZnO NW). The liquid surrounding the ZnO NW creates an electrochemical double layer (EDL) on the NW surface which in turn gives rise to the gate capacitance. The resulting gating effect can be used to modulate the NW conductance depending on the voltage applied through the liquid. The ZnO NW transistors showed a current modulation of up to 6 orders of magnitude, high field-effect mobilities (around 1.85 cm2/Vs) and sub-threshold slopes as low as 105 mV/decade. This is the first demonstration of liquid-gated FETs using ZnO NWs. The liquid-gated FETs are used as a basic device for further sensing trials in liquids. For this purpose, the FETs were functionalized with receptor molecules. These so called ion-selective FETs (ISFETs) were demonstrated as functional pH sensors for liquids with pH values from 6 to 10. The NWs functionalized with analyte-sensitive molecules on their surface are influenced electrically by the presence of analytes in the surrounding liquid. Any change in the amount of analyte present in the surrounding liquid is thus reflected in the electrical transport characteristics of the FET. 3-aminopropyltriethoxysilane (3-APTES) molecules were used to functionalize the ZnO NWs in order to construct the pH sensors. Subsequently, the realization of a biosensor based on ZnO NW transistors is demonstrated. Label-free direct detection of urea molecules was carried out from a solution of urea in buffer. ZnO NWs were electrochemically functionalized with the enzyme urease incorporated into an electro-polymerized polypyrrole matrix. Urease molecules act as specific receptors for urea molecules and catalyze an enzymatic reaction. This reaction causes a pH change in the vicinity of NWs, which is reflected in the field-effect characteristics of transistor. The performance of liquid-gated ZnO NW FETs used as chemical and biological sensor can be further improved by employing a metal gate in liquid medium. This was established by fabricating liquid gated metal-semiconductor FET (MESFET) based on ZnO NWs. ZnO NWs were decorated with metal nanoparticles (NPs) by using an electrochemical deposition method. The NPs were then used as metal gate and devices were characterized by applying a gate voltage on the NPs through the liquid. The realization of metal-semiconductor gate in liquids considerably improved the field-effect characteristics of liquid-gated FETs based on ZnO NWs. The realization of high performance liquid-gated transistors based on ZnO NWs thus constitutes a suitable platform for label-free detection of biomolecules and shows promise for future applications in chemical analysis and medical diagnostics

Field-effect-based chemical sensing using nanowire-nanoparticle hybrids: The ion-sensitive metal-semiconductor field-effect transistor

A new class of nanoscale devices called ion-sensitive metal-semiconductor field-effect transistors (nano-IS-MESFET) for sensing applications is reported. Nanoparticle-nanowire hybrids with active metal-semiconductor regions are operated as ion-sensitive field-effect transistors (ISFETs) in liquids, where 0D metal gates induce quasi-spherical charge depletion regions in 1D transport channel producing stronger field-effects. As a proof-of-concept, we present ZnO nanowire-Pd/Au nanoparticle IS-MESFETs that show increased transconductance in comparison to ZnO nanowire ISFETs. As demonstrated further, ISMESFETs may also provide strategies for site-specific immobilization of receptor molecules paving way towards a novel electrical biosensing platform operable at low voltages with improved selectivity and sensitivity. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4775579

Template-free self-assembly of hierarchical ZnO structures from nanoscale building blocks

We study chemical bath deposition method for synthesizing large variety constructions of ZnO nanostructures. By varying reaction kinetics we control the shape, size and morphology to yield flower-like, rolling-pin-like, viscous-fingers-like and antenna-like structures. In solution-based methods, factors responsible for crystal growth are largely affected by slight changes in the reaction processes/conditions and cause different hierarchical architectures when very low concentrations of precursor material used. The ability to grow different morphologies just by controlling solution growth parameters may open up new avenues to solution growth and provide systems to study natural growth behavior of materials as well as their novel applications. (C) 2010 Elsevier B.V. All rights reserved

Chemically exfoliated large-area two-dimensional flakes of molybdenum disulfide for device applications

A solution-based exfoliation method for obtaining large-area two-dimensional flakes of molybdenum disulfide, followed by the fabrication of electrical devices is presented in this manuscript. The exfoliation method is based on the use of an aprotic solvent, namely, acetonitrile under mild sonication steps. In order to fabricate devices, a dielectrophoresis technique is used for transferring MoS2 flakes site-specifically on to the electrode pairs pre-written on the glass chips. The devices fabricated thus can be operated as chemical sensor in liquids while investigations under photo illumination indicate that such devices can also efficiently function as photodetectors

Site-Specific Self-Assembled Liquid-Gated ZnO Nanowire Transistors for Sensing Applications

A scalable bottom-up solution-based approach for the site-specific realization of ZnO nanowire (ZnO-NW)-based field-effect transistors for sensing applications in liquids is reported. The nanowires are grown across pre-defined electrodes patterned by photolithography. Site specificity is attained by the use of nanoparticles acting as seeds. Using integrated on-chip microchannels and microfabricated gate electrodes, electrochemically gated ZnO-NW network transistors functioning in liquids are demonstrated. The optimized devices are rendered sensitive to pH through chemical functionalization. The unique combination of the sensitivity, site specificity, scalability, and cost effectiveness of the technique opens up avenues for the routine realization of one-dimensional nanostructure-based chemical and biosensors for analytical and diagnostic applications

Process Variability in Top-Down Fabrication of Silicon Nanowire-Based Biosensor Arrays

Silicon nanowire field-effect transistors (SiNW-FET) have been studied as ultra-high sensitive sensors for the detection of biomolecules, metal ions, gas molecules and as an interface for biological systems due to their remarkable electronic properties. “Bottom-up” or “top-down” approaches that are used for the fabrication of SiNW-FET sensors have their respective limitations in terms of technology development. The “bottom-up” approach allows the synthesis of silicon nanowires (SiNW) in the range from a few nm to hundreds of nm in diameter. However, it is technologically challenging to realize reproducible bottom-up devices on a large scale for clinical biosensing applications. The top-down approach involves state-of-the-art lithography and nanofabrication techniques to cast SiNW down to a few 10s of nanometers in diameter out of high-quality Silicon-on-Insulator (SOI) wafers in a controlled environment, enabling the large-scale fabrication of sensors for a myriad of applications. The possibility of their wafer-scale integration in standard semiconductor processes makes SiNW-FETs one of the most promising candidates for the next generation of biosensor platforms for applications in healthcare and medicine. Although advanced fabrication techniques are employed for fabricating SiNW, the sensor-to-sensor variation in the fabrication processes is one of the limiting factors for a large-scale production towards commercial applications. To provide a detailed overview of the technical aspects responsible for this sensor-to-sensor variation, we critically review and discuss the fundamental aspects that could lead to such a sensor-to-sensor variation, focusing on fabrication parameters and processes described in the state-of-the-art literature. Furthermore, we discuss the impact of functionalization aspects, surface modification, and system integration of the SiNW-FET biosensors on post-fabrication-induced sensor-to-sensor variations for biosensing experiments