Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Department of Physics

Fabrication, physical modeling and dynamic response of p -type Al-doped SnOx active channel thin film transistors (TFTs) are presented for the potential application of ultra-high definition (UHD) displays. After deposition of Al-doped SnOx active layer using reactive co-sputtering, the channel was treated with plasma fluorination which improve the device performance of high ION/IOFF ratio of &gt; 106, low subthreshold swing of 100 mV/dec and high field-effect mobility ( μ FE) of 4.8 cm2V-1s-1. To understand the origin of such high performance, physical modeling and numerical simulations were performed using density of state (DOS) model of defects/traps of oxide semiconductor. This model describes the modifications of donor-like tail states and acceptor-like Gaussian defect states due to Al doping on SnOx and fluorine treatment. To evaluate the device performance for UHD large scale displays, the dynamic responses of p -type TFT pixel circuit for various requirements are simulated with physical models. These results suggest that the Al-doped SnOx TFTs are potential candidates for future high-definition displays and many applications in transparent electronics. © 2013 IEEE.

World University root node

Centre for Nanotechnology Research

Vellore Campus

Department of Communication Engineering

School of Electronics Engineering

School of Advanced Sciences

Fulltext

IEEE Journal of the Electron Devices Society

Physical Modeling of p-Type Fluorinated Al-Doped Tin-Oxide Thin Film Transistors

Luminescent solar concentrators (LSCs) are panels made of polymers which are doped with fluorescent dye or quantum dots. In space-limited urban areas where deploying solar cells on a large scale is inconvenient, LSC panels can be installed on vertical structures to collect maximum solar radiation. These structures which collect solar radiation, guide the light towards edges of the panel where solar converters are located. Solar converters for large-scale deployment make use of photovoltaic or nano-antenna technology. The latter has the advantage of being able to work at nighttime by making use of infrared radiation re-emitted by earth. It is possible to increase the efficiency of LSCs by employing novel approaches which make use of stimulated emission. In this manner, LSCs can increase the share of solar energy use in urban areas. © 2020, Indian Academy of Sciences.

Current Science

Light harvesting using solar cells and luminescent solar concentrators

The optimized concentration of oxygen vacant sites along with surface spin alignment in the nanoparticles can lead to the origin of ferromagnetism in them. So in this work, indium-tin-oxide was doped with iron by varying the concentration of Fe. Thus, cubic structured iron doped indium tin oxide nanoparticles were obtained with increasing crystallinity. Even the relative intensity ratio was found to be below 29% suggesting the optimization of amount of oxygen vacancies. Room temperature ferromagnetism was observed in case of Fe: ITO nanoparticles. © 2020 Author(s).

AIP Conference Proceedings

Synthesis and characterization of Fe doped ITO nanoparticles

In this study, by the method of co-precipitation with PEG as surfactant as agent nanocomposite of the Copper Zinc Cobalt ferrites systems (CuZnCoFO NCs) are prepared. The X-ray diffraction (XRD), transmission electron microscopy, and field emission scanning electron microscopy of the samples are carried out. To analyse the magnetic measurements the samples are subjected to the vibrating sample magnetometer (VSM). The results of the paramagnetic properties formed out of chemical precipitation method are effective at room temperature. These ferrite system nanoparticles with magnetic fields could have effective application. The photocatalyst activity when annealed at 600ºC at 2h NPs is also evaluated by Methylene Blue degradation when exposed to ultraviolet light irradiation. © 2020 by the authors.

Biointerface Research in Applied Chemistry

Structural, morphological, and magnetic properties of copper zinc cobalt ferrites systems nanocomposites

Development of stable and optically active composite film that can show efficient supercapacitor activity is a challenging research interest in material science. A polymer nanocomposite film composed of a green synthesised graphene quantum dot (GQD, G) doped polyacrylonitrile (PAN) and polyaniline (PANI) systems, designated as PAN-PANI@G, have been prepared. The critical loading concentration of prepared composite and its effect on the physicochemical, optical and electrical analysis were systematically studied in detail. PAN-PANI@G composite showed an appreciable electrical conductivity (2.362 × 10−6 S m−1) and optical absorbance at λmax ~270 nm. Physicochemical characterizations by XRD, FTIR and TEM analysis reveal chemical interaction between the individual components via intermolecular hydrogen bonding. Analysed particle size of GQD in the polymer membrane was found to be about two times lesser than that of the pure GQD highlighting synergic interaction between the individual GQD and PAN/PANI matrix. A specific capacitance value of the polymer composites that have been modified on screen-printed carbon electrode were tested by cyclic voltammetric and galvanostatic charge-discharge techniques in 0.1 M H2SO4 solution. Calculated supercapacitor values at an applied current density, 670 mA g−1 are in a range of 105–587 F g−1 cm−2 which are approximately 2–1300 times higher than the values reported for polypyrrole and polyaniline based polymer composite film in the literature. As a preliminary extension of this study, the optimal PAN/PANI@G nanocomposite of GQD loading, 1.5 wt% was extended to prototype supercapacitor cell application in combination with a dilute solution of NaCl along with suitable conducting plates. When 3 V DC power was supplied for 4 min, the prototype cell produced an operating voltage of 1.4 V for 1 h of operating time. © 2020 Hydrogen Energy Publications LLC

International Journal of Hydrogen Energy

Optically active polymer nanocomposite composed of polyaniline, polyacrylonitrile and green-synthesized graphene quantum dot for supercapacitor application

Node starvation wireless sensor network (WSN) is a critical factor that affects the overall performance in a typical multi-hop linear network especially in an extensive scale network. The unfairness of sharing network resources with all source nodes in a multi-hop linear network amplifies the node starvation that often results in passive nodes in a network. This factor becomes critical with the increasing network density, aggressive data transfer, single destination node and inadequate data scheduling. This paper highlights the Delayed acknowledgement timeout for flat one-tier throughput critical application model (DAT-FTCAM) a mathematical fairness model that ensure maximum throughput fairness for pipeline network scenario. The DAT-FTCAM enables the users to calculate the maximum delayed acknowledgement timeout for transmission control protocol (TCP) proportional to the travel time or difference between a source and a destination node. The implementation of DAT-FTCAM technique with modified TCP parameters on NS2 has revealed a network fairness index of above 0.99 with optimum network performance in a scalable pipeline network. The DAT-FTCAM decreases data packet collision and eliminates passive nodes in a pipeline network with optimum throughput fairness.

Department of Chemistry

International Journal of Recent Technology and Engineering Special Issue

Tcp Performance and Throughput Fairness Optimization in a Multi-Hop Pipeline Network

Nanoparticles of Zinc Sulfide (ZnS) co-doped with Tin (Sn) and Nickel (Ni) have been synthesized using solid state reaction and the nanoparticles were then deposited on to glass substates by physical vapour deposition technique. The structural, morphological, optical and magnetic properties of the prepared nanoparticles and thin films were analyzed in detail. Single phase cubic structure was observed for both nanoparticles and thin films. The optical band gap became narrower for co-doped nanoparticles compared to the individually doped nanoparticles. The co-doped thin films showed a maximum transmittance (93%) in the visible region. The co-doped nanoparticles exhibited soft ferromagnetic nature at room temperature, while room temperature paramagnetic nature was observed in co-doped thin films. © 2019 Elsevier Ltd

VIT Unitversity

Materials Science in Semiconductor Processing

Effect of (Sn, Ni) co-doping on structural, optical and magnetic properties of ZnS Nanoparticles and thin films

Composite metal oxide based thin film based sensors are proposed to eradicate the problems faced by the single phase materials. The composite thin films of ZnO and SnO2 are expected to have significantly enhanced humidity sensing properties. In the present work, pure and composite thin films of ZnO and SnO2 are prepared by sol-gel based spin coating. The structural, optical and morphological properties of the films were studied by X-ray diffraction, Ultraviolet-Visible absorption spectroscopy and the scanning electron microscopy. The composite films with different compositions of ZnO and SnO2 phase were studied for their impedometric humidity sensing characteristics. Among the proposed sensors, the zinc rich composite sensors exhibit the maximum sensor response of 95% and sensitivity of 8.6 ± 0.5 kΩ/RH%. Further, the composite metal oxide based humidity sensors exhibit better transient characteristics and significantly lower hysteresis compared to their pure counterparts. © 2019 Elsevier B.V.

Department of Sensor and Biomedical Technology

Sensors and Actuators B: Chemical

Composite metal oxide thin film based impedometric humidity sensors

Journal of Stored Products Research

Genetic diversity and its geographic structure in Sitophilus oryzae (Coleoptera; Curculionidae) across India – implications for managing phosphine resistance

Nickel (Ni) incorporated zinc sulfide (Zn1−xNixS) thin films at different Ni concentrations (x = 0.00, 0.02, 0.05, 0.08 and 0.10) were prepared by EB technique. The effect of Ni concentration on structural, morphological, optical and magnetic properties were studied using different characterization methods including X-ray diffraction, atomic force microscopy (AFM), scanning electron microscopy, energy dispersive analysis of X-ray (EDX), UV-Vis-NIR spectroscopy, photoluminescence (PL) spectroscopy and a vibrating sample magnetometer.The Ni-doped ZnS thin films exhibited cubic structure with preferred orientation along (1 1 1) orientation. The average crystallite size was about 20 nm. The AFM images indicated dense and homogeneous particles on the surface of the films with good and compact grain connectivity. The EDX spectra showed the presence of host and dopant elements in prepared thin films. The thin films showed high optical transmittance in the visible region and increased from 80 to 88% with increasing Ni concentration from x = 0.00 to x = 0.10. The optical band gap decreased from 3.46 to 3.25 eV with increasing Ni concentration. A broad emission peak at 463 nm was observed from the PL spectra. The undoped and Ni-doped ZnS thin films exhibited weak ferromagnetism at room temperature. © 2019 Elsevier Ltd