01746nas a2200181 4500008004100000245007300041210006900114260000800183300002700191490000800218520112800226100002401354700002001378700002201398700002001420700001901440856010501459 2016 eng d00aThickness tunable transport in alloyed WSSe field effect transistors0 aThickness tunable transport in alloyed WSSe field effect transis cOCT aArticle Number: 1421010 v1093 aWe report the field effect transistor characteristics of exfoliated transition metal dichalcogenide alloy tungsten sulphoselenide. WSSe is a layered material of strongly bonded S-W-Se atoms having weak interlayer van der Waals forces with a significant potential for spintronic and valleytronic applications due to its polar nature. The X-ray photoelectron spectroscopy measurements on crystals grown by the chemical vapor transport method indicate a stoichiometry of the form WSSe. We report flake thickness tunable transport mechanism with n-type behavior in thin flakes (<= 11 nm) and ambipolarity in thicker flakes. The devices with flake thicknesses of 2.4 nm-54.8nm exhibit a maximum electron mobility of similar to 50 cm(2)/V s along with an I-ON/I-OFF ratio > 10(6). The electron Schottky barrier height values of 35 meV and 52meV extracted from low temperature I-V measurements for 3.9 nm and 25.5 nm thick flakes, respectively, indicate that an increase in hole current with thickness is likely due to lowering of the bandgap through an increase in energy of the valence band maximum. Published by AIP Publishing.1 aKarande, Shruti, D.1 aKaushik, Naveen1 aNarang, Deepa, S.1 aLate, Dattatray1 aLodha, Saurabh uhttps://library.ncl.res.in/content/thickness-tunable-transport-alloyed-wsse-field-effect-transistors01985nas a2200229 4500008004100000245010700041210006900148260000800217300002800225490000800253520119900261100001901460700001801479700002101497700002001518700001801538700002001556700001801576700001901594700002001613856012201633 2017 eng d00aSynthesis of gamma-WO3 thin films by hot wire-CVD and investigation of its humidity sensing properties0 aSynthesis of gammaWO3 thin films by hot wireCVD and investigatio cMAY aArticle Number: 16007170 v2143 aIn this study, monoclinic tungsten oxide (gamma-WO3) have been grown in a single step using HW-CVD method by resistively heating W filaments in a constant O-2 pressure. The formation of gamma-WO3 was confirmed using low angle-XRD and Raman spectroscopy analysis. Low angle-XRD analysis revealed that as-deposited WO3 film are highly crystalline and the crystallites have preferred orientation along the (002) direction. HRTEM analysis and SAED pattern also show the highly crystalline nature of WO3 with d spacing of similar to 0.38 nm, having an orientation along the (002) direction. Surface topography investigated by SEM analysis shows the formation of a uniform and homogeneous cauliflower like morphology throughout the substrate surface without flaws and cracks. A humidity sensing device incorporating WO3 is also fabricated, which shows a maximum humidity sensitivity factor of similar to 3954% along with a response time of similar to 14 s and a recovery time of similar to 25 s. The obtained results demonstrate that it is possible to synthesize WO3 in a single step by HW-CVD method and to fabricate a humidity sensor by using it. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim1 aJadkar, Vijaya1 aPawbake, Amit1 aWaykar, Ravindra1 aJadhavar, Ashok1 aDate, Abhijit1 aLate, Dattatray1 aPathan, Habib1 aGosavi, Suresh1 aJadkar, Sandesh uhttps://library.ncl.res.in/content/synthesis-gamma-wo3-thin-films-hot-wire-cvd-and-investigation-its-humidity-sensing02002nas a2200205 4500008004100000022001400041245010600055210006900161260000900230300001200239490000700251520129400258100002101552700001601573700002001589700002001609700001801629700002401647856012501671 2019 eng d a0740-322400aFiber optic Fabry-Perot interferometer sensor: an efficient and fast approach for ammonia gas sensing0 aFiber optic FabryPerot interferometer sensor an efficient and fa cMAR  a684-6890 v363 a

In this work, we propose and demonstrate a Fabry-Perot-interferometer-based polydimethylsiloxane (PDMS) and poly(methyl methacrylate) (PMMA)-composite-coated optical sensor for ammonia and volatile organic compounds (VOCs) detection at room temperature. The principle of sensing is based on change in the cavity length of the FP cavity in the presence of varied concentrations of gases, which results in changes in the total reflectance due to the shift in wavelength of an interference pattern. The sensing composite material was coated on a single-mode optical fiber by using a simple dip-coating technique and explored it for sensing. The ammonia and VOCs measurements were performed for concentrations ranging from 5 to 500 ppm. The corresponding sensitivity and limit of detection of the developed sensor for ammonia gas detection was observed of the order of around 4.16 pm/ppm and 4.8 ppm, respectively. The response and recovery times of the sensor were found to be of the order of 50 s and 10 s, respectively, for the ammonia gas. This sensor provides a simple, cost-effective, highly sensitive, and repeatable approach to measure ammonia gas and other VOCs at room temperature and could fulfill the demands of industrial applications. (C) 2019 Optical Society of America

1 aKanawade, Rajesh1 aKumar, Ajay1 aPawar, Dnyandeo1 aLate, Dattatray1 aMondal, Samir1 aSinha, Ravindra, K. uhttps://library.ncl.res.in/content/fiber-optic-fabry-perot-interferometer-sensor-efficient-and-fast-approach-ammonia-gas02231nas a2200229 4500008004100000022001400041245009600055210006900151260000900220300001400229490000700243520146300250100002201713700001601735700002001751700002101771700002001792700002001812700002401832700001801856856012701874 2019 eng d a1094-408700aNegative axicon tip-based fiber optic interferometer cavity sensor for volatile gas sensing0 aNegative axicon tipbased fiber optic interferometer cavity senso cMAR  a7277-72900 v273 a

In this research work we demonstrated negative axicon optical fiber tip filled with Polydimethylsiloxane (PDMS) as a sensor platform for volatile organic gases detection at room temperature. The response of the sensor was measured with various Volatile Organic Compounds (VOCs) such as Chloroform, Hexane, Isopropanol, Acetone, Toluene and Methanol in the concentration ranging from 5 to 200 ppm. The corresponding sensitivity and limit of detection (LOD) of the developed sensor for the measured VOCs were observed between the order of around 23.7 to 3.2 pm/ppm and 0.84 to 6.10 ppm, respectively. The response and recovery time of sensor were found between the order of 30 to 57 seconds and 8 to 25 seconds respectively for the measured VOCs. Thermal stability of the developed sensor was also studied at 30-70 degrees C with intervals of 10 degrees C. The principle of sensing is based on change in the length of the Fabry-Perot Interferometric (FPI) cavity in the presence of varied concentrations of VOCs, which results in changes in the shift in wavelength of an interference pattern attributed to the change in PDMS filling the cavity length (swelling). The experimentally observed trends in the relative swelling of PDMS with VOCs are found in agreement with the theoretically calculated values obtained from the Hansen solubility parameter (HSP). The developed gas sensor has the potential to fulfill the demands of industrial applications.

1 aKanavvade, Rajesh1 aKumar, Ajay1 aPawar, Dnyandeo1 aVairagi, Kaushal1 aLate, Dattatray1 aSarkar, Sudipta1 aSinha, Ravindra, K.1 aMondal, Samir uhttps://library.ncl.res.in/content/negative-axicon-tip-based-fiber-optic-interferometer-cavity-sensor-volatile-gas-sensing02586nas a2200325 4500008004100000022001400041245011200055210006900167260000800236300001200244490000800256520159300264653002001857653001301877653001801890653000801908653000801916100001601924700002001940700001801960700002101978700002401999700001902023700001902042700001702061700002002078700001802098700002002116856012402136 2019 eng d a1862-630000aSolvothermal growth of PbBi2Se4 nano-flowers: a material for humidity sensor and photodetector applications0 aSolvothermal growth of PbBi2Se4 nanoflowers a material for humid cJUN a19000650 v2163 a

In the present work, lead bismuth selenide (PbBi2Se4) nano-flowers are synthesized by using a simple solvothermal method. Humidity sensor and photodetector based on PbBi2Se4 nano-flowers are fabricated on indium tin oxide (ITO) substrates and their sensing properties are investigated. Formation of PbBi2Se4 is confirmed by XRD, EDS, and XPS whereas formation of nano-flowers is confirmed by SEM and TEM analysis. XRD analysis reveals the hexagonal crystal structure of PbBi2Se4 phase with a = b = 4.22 angstrom, and c= 17.42 angstrom. The surface morphology of PbBi2Se4 clearly shows the formation of well-organized flower-like nanostructures which closely resembles the shape of Dahlia. The elemental mapping of chemical constituents obtained from SEM-EDS analysis shows uniform distribution of chemical constituents for the Pb, Bi, and Se in PbBi2Se4 nano-flowers. The PbBi2Se4 nano-flowers based humidity sensor has a typical response time of approximate to 65s and recovery time of approximate to 75 s. In case of PbBi2Se4 nano-flowers-based photodetector, the response and recovery time are observed approximate to 121 and approximate to 123 s, respectively, under visible light illumination with photoresponsivity (5 x 10(-6)), photosensitivity (2.16%), and quantum efficiency (1.5 x 10(4)). The obtained results demonstrate the potential applications of solvothermally grown PbBi2Se4 nano-flowers-based devices for humidity sensors and photodetectors. The ease of the present work is to develop novel material to obtain device quality humidity sensors and photodetectors.

10ahumidity sensor10aPbBi2Se410aphotodetector10aXPS10aXRD1 aAher, Rahul1 aBhorde, Ajinkya1 aNair, Shruthi1 aBorate, Haribhau1 aPandharkar, Subhash1 aNaik, Dhirsing1 aVairale, Priti1 aKarpe, Smita1 aLate, Dattatray1 aPrasad, Mohit1 aJadkar, Sandesh uhttps://library.ncl.res.in/content/solvothermal-growth-pbbi2se4-nano-flowers-material-humidity-sensor-and-photodetector