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

A self-aligning system of single transmitter multiple receivers to design a multiplexer like a channel that transmits data over the free space opticallink[1]. The system is divided into two sectors. One is the channel over which the communication of transmitters and receivers occur. The second part of the system provides alignment control which bypasses the need for manual alignment of transmitter and receiver. Now as the communication is a point to point[6], thus the second phase of the project is very sophisticated as even a single shift in angle can cause disruption in communication.

VIT Unitversity

School of Electronics Engineering

Chennai Campus

2018 Second International Conference on Electronics, Communication and Aerospace Technology (ICECA)

Auto Aligning Laser Communication System

The surface conductivity of metal oxide based gas sensors are influenced by the composition of gases or gas/air mixture in the gas sensing environment. Native metal oxide based gas sensors like SnO2, ZnO and TiO2 have been exploited in the recent past to study their sensing abilities and selectivity towards various gases. The research carried in the recent years are aimed at adding variety of dopants mostly metal based dopants with the metal oxide semiconductor based gas sensors. The sensing mechanism involves small quantities of reducing or oxidizing gases interacting with the metal oxide sensing layer by means of chemisorption or physisorption. The sensing mechanism depends on reversible adsorption or desorption processes of the gas at semiconductor surfaces. The sensing layers are tailored made to be selective towards different gases by selecting dopants, optimal sensor temperatures, catalysts, synthesis and film fabrication techniques. Metals are doped in metal oxide primarily to enhance their conducting ability for a particular level of gas sample there by increasing the sensitivity of the metal oxide gas sensor. More over the doping also increases the selectivity of the metal oxide gas sensors towards a particular gas. The process of doping mostly involves replacing a metal atom in the crystal lattice of the metal oxide with the dopant. This leads to the change in the sensing layer resistance by several orders of magnitude. The review aims at exploring the dopants added to metal oxide semiconductor materials which can be used to sense variety of gases.

Centre for Nanotechnology Research

Vellore Campus

Sensor Letters

Metal/Metal Oxide Doped Semiconductor Based Metal Oxide Gas Sensors—A Review

A simple process of gas sensing is represented here using Ce doped tin oxide nanomaterial based thin film sensor. A novel flow metric gas chamber has been designed and utilized for gas sensing. Doping plays a vital role in enhancing the sensing properties of nanomaterials. Ce doped tin oxide was prepared by hydrothermal method and the same has been used to fabricate a thin film for sensing. The microstructure and morphology of the prepared materials were analysed by SEM, XRD, and FTIR analysis. The SEM images clearly show that doping can clamp down the growth of the large crystallites and can lead to large agglomeration spheres. Thin film gas sensors were formed from undoped pure SnO2and Ce doped SnO2. The sensors were exposed to ammonia and ethanol gases. The responses of the sensors to different concentrations (50–500 ppm) of ammonia and ethanol at different operating temperatures (225°C–500°C) were studied. Results show that a good sensitivity towards ammonia was obtained with Ce doped SnO2thin film sensor at an optimal operating temperature of 325°C. The Ce doped sensor also showed good selectivity towards ammonia when compared with ethanol. Pure SnO2showed good sensitivity with ethanol when compared with Ce doped SnO2thin film sensor. Response time of the sensor and its stability were also studied.

Fulltext

Journal of Sensors

Temperature Optimized Ammonia and Ethanol Sensing Using Ce Doped Tin Oxide Thin Films in a Novel Flow Metric Gas Sensing Chamber

Tin oxide is a wide band gap /Mype semiconductor and has the capability to detect various reducing gases and organic vapours. The sensitivity towards different gases and organic vapours in high temperature environment is already reported. The present work is focused on the development of soft chemical route derived SnO2 nanostructures to detect organic vapours. The ethanol sensing properties of the derived nanostructures of SnO2 was analyzed. X-Ray diffraction, UV-Vis spectroscopy, scanning electron microscope and energy dispersive spectroscope characterizations have been performed to confirm the SnO2 nanostructure formation. The optimum temperature for sensor operation towards 50 ppm of ethanol has also been found. © 2015 Scientific Publishers. All Rights Reserved.

World University root node

Department of Chemistry

School of Advanced Sciences

Journal of the Indian Chemical Society

Structural, optical, morphological and organic vapours sensing properties of SnO2nanostructures

Gas monitoring devices consisting of metal oxide thin films have been very widely applied as chemical sensors. They find profound use towards detection of toxic pollutant gases and organic vapors. They provide beneficiary merits as large scale commercial sensors owing to their low price, small size, high sensitivity and consume very low power. Ethanol is one of the most commonly and extensively used alcohol, both in the fields of research and industrial applications. There is an imminent need to develop sensors for its detection with very sensitivity. In this study, Zinc oxide nanoparticles were prepared by a suitable soft chemical method. ZnO thick films were prepared from these nanoparticles by dip coating method. ZnO thick films are coated on an Alumina substrate and the sensor is tested for ethanol for 50 ppm at various temperatures. The sensor was found to operate with maximum efficiency at an optimum temperature of 350°C.

Department of Sensor and Biomedical Technology

Journal of Applied Sciences

Ethanol Sensor Based on Dip Coated ZnO Thick Films

Health

Simulation of perforated rectangular cantilever immunosensor for estimation of bacterial pathogens

Humidity plays a very major role in various industries. Monitoring and controlling the humidity is of great importance for the reliable operation of various systems. Micro cantilever systems have been found to be highly suited for sensing purposes. A micro cantilever humidity sensor based on capacitive principle is designed and various analyses were performed on the sensor. The polyimide being the sensing layer is coated on the cantilever beam. The beam is provided with movable electrode. The deflection of beam causes capacitance change, which is related to the change in humidity. The design also incorporates a platinum based temperature sensor to compensate for change in humidity due to temperature and also a platinum based heater to regenerate the sensing layer for obtaining next measurement. The structure was designed using Coventorware and Intellisuite. The structure showed a good linearity and good sensitivity in the regions from 10-40 % RH in all temperatures in human adaptive ranges. The beam had an appreciable deflection causing a notable change in capacitance. The sensitivity was in order of pico to femto farads per %RH change.