02462nas a2200253   4500008004100000022001400041245013900055210006900194260007100263300001400334490000600348520151800354653003001872653002001902653001701922653001601939653001401955653002301969100002201992700002502014700002402039700002402063856012102087       2016                        eng d  a1944-824400aHighly transparent wafer-scale synthesis of crystalline WS2 nanoparticle thin film for photodetector and humidity-sensing applications0 aHighly transparent waferscale synthesis of crystalline WS2 nanop  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a3359-33650 v83 a<p>In the present investigation, we report a one-step synthesis method of wafer-scale highly crystalline tungsten disulfide (WS2) nanoparticle thin film by using a modified hot wire chemical vapor deposition (HW-CVD) technique. The average size of WS2 nanoparticle is found to be 25-40 nm over an entire 4 in. wafer of quartz substrate. The low-angle XRD data of WS2 nanoparticle shows the highly crystalline nature of sample along with orientation (002) direction. Furthermore, Raman spectroscopy shows two prominent phonon vibration modes of E12g and A1g at similar to 356 and similar to 420 cm(-1), respectively, indicating high purity of material. The TEM analysis shows good crystalline quality of sample. The synthesized WS2 nanoparticle thin film based device shows good response to humidity and good photosensitivity along with good long-term stability of the device. It was found that the resistance of the films decreases with increasing relative humidity (RH). The maximum humidity sensitivity of 469% along with response time of similar to 12 s and recovery time of similar to 13 s were observed for the WS2 thin film humidity sensor device. In the case of photodetection, the response time of similar to 51 s and recovery time of similar to 88 s were observed with sensitivity similar to 137% under white light illumination. Our results open up several avenues to grow other transition metal dichalcogenide nanoparticle thin film for large-area nanoelectronics as well as industrial applications.</p>10achemical vapor deposition10ahumidity sensor10ananoparticle10aphotosensor10athin film10atungsten disulfide1 aPawbake, Amit, S.1 aWaykar, Ravindra, G.1 aLate, Dattatray, J.1 aJadkar, Sandesh, R.  uhttps://library.ncl.res.in/content/highly-transparent-wafer-scale-synthesis-crystalline-ws2-nanoparticle-thin-film-002932nas a2200241   4500008004100000022001400041245009600055210006900151260000800220300001000228490000800238520213400246653002002380653001502400653001502415653001902430100002502449700002202474700002302496700002402519700002202543856012502565       2019                        eng d  a0925-400500aSuperior humidity sensor and photodetector of mesoporous ZnO nanosheets at room temperature0 aSuperior humidity sensor and photodetector of mesoporous ZnO nan  cAUG  a83-920 v2933 a<p>Miniaturized sensor technology is vastly demanding multifunctional materials to fulfill many requirements simultaneously; instead of integrating various sensors into a single device. Efficient operation of these miniaturized sensors at room temperature is highly feasible and cost-effective. The humidity sensing and photodetection is precise merit of sensing in special usage like artificial skin. Sensitivity enhancement in both humidity and photodetection required the high surface area for adsorption as well as a high charge transfer mechanism. The two dimensional (2D) zinc oxide nanosheets (ZnO NS) is the ultimate structure for dimensionally confined transport properties owing to the specific surface atomic configuration that results in high sensitivity, low operating temperature, fast response and recovery, and improved selectivity. Furthermore, introducing porosity into 2D nanostructures has opened new opportunities to enhance the efficiency of sensors and detectors via increasing large surface area and tunable physical and chemical properties. Here we report preparation of mesoporous and highly crystalline 2D ZnO NS by a single step, template free, cost-effective chemical method. The structural and morphological characterizations of ZnO NS are carried out using XRD, FESEM, XPS, TEM respectively. The high-resolution TEM images emphasize sheet-like morphology with a thickness of around 18-22 nm. Further the mesoporous ZnO NS (MZNS) with the pore size between 5-10 nm are achieved by simple heat-treatment. XPS and PL study is confirming the oxygen deficiency in MZNS. The MZNS exhibits an excellent responsivity than PZNS with a fast response and rapid recovery time of 25 s and 5 s respectively along with good cyclic stability which is highly crucial for smart humidity sensor. Furthermore, it considerably enhances photo-sensor performance than pristine ZnO NS (PZNS) with (similar to)1 s response time as well as (similar to)1 s recovery time along with better stability. These promising results illustrate the great potential of MZNS for next-generation humidity sensors and photodetectors.</p>
10ahumidity sensor10aMesoporous10ananosheets10aPhoto-detector1 aGupta, Shobhnath, P.1 aPawbake, Amit, S.1 aSathe, Bhaskar, R.1 aLate, Dattatray, J.1 aWalke, Pravin, S.  uhttps://library.ncl.res.in/content/superior-humidity-sensor-and-photodetector-mesoporous-zno-nanosheets-room-temperature