01566nas a2200181 4500008004100000022001400041245014600055210006900201260011000270300001400380490000600394520076000400100002201160700002401182700002401206700002401230856013001254 2016 eng d a2040-336400aLarge area chemical vapor deposition of monolayer transition metal dichalcogenides and their temperature dependent Raman spectroscopy studies0 aLarge area chemical vapor deposition of monolayer transition met aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN a3008-30180 v83 a

We investigate the growth mechanism and temperature dependent Raman spectroscopy of chemical vapor deposited large area monolayer of MoS2, MoSe2, WS2 and WSe2 nanosheets up to 70 mu m in lateral size. Further, our temperature dependent Raman spectroscopy investigation shows that softening of Raman modes as temperature increases from 80 K to 593 K is due to the negative temperature coefficient and anharmonicity. The temperature dependent softening modes of chemical vapor deposited mono-layers of all TMDCs were explained on the basis of a double resonance phonon process which is more active in an atomically thin sample. This process can also be fundamentally pertinent in other emerging two-dimensional layered and heterostructured materials.

1 aPawbake, Amit, S.1 aPawar, Mahendra, S.1 aJadkar, Sandesh, R.1 aLate, Dattatray, J. uhttp://library.ncl.res.in/content/large-area-chemical-vapor-deposition-monolayer-transition-metal-dichalcogenides-and-their-001765nas a2200157 4500008004100000245009700041210006900138260000800207300001800215490000600233520117000239100002801409700002301437700002401460856012301484 2016 eng d00aLaser exfoliation of 2D black phosphorus nanosheets and their application as a field emitter0 aLaser exfoliation of 2D black phosphorus nanosheets and their ap cNOV a112103-1121080 v63 aHighly crystalline two dimensional (2D) few layered black phosphorus (BP) nanosheets have been synthesized via a one step facile laser irradiation technique under optimized experimental conditions. The field emission investigations on the few layered black phosphorus nanosheets were carried out at the base pressure 1 x 10(-8) mbar. The morphological, elemental, optical, and structural analysis of the as-synthesized black phosphorus sample was carried out using SEM, AFM, EDAX, TEM, and Raman spectroscopy. The turn-on values of the BP nanosheets emitter were found to be significantly lower than that of earlier reports of BP nanosheets, graphene, and carbon nanotubes based field emitters due to the high field enhancement factor (beta) similar to 2986 associated with atomically thin/sharp edges of the BP nanosheets emitter. The emission current versus time plot depicts the good emission current stability with a pre-set value of 1 mu A for similar to 5 h duration. Our facile synthesis approach and the robust field emitter nature of the BP nanosheets makes them a potential candidate for a practical electron source in vacuum micro/nanoelectronic devices.1 aSuryawanshi, Sachin, R.1 aMore, Mahendra, A.1 aLate, Dattatray, J. uhttp://library.ncl.res.in/content/laser-exfoliation-2d-black-phosphorus-nanosheets-and-their-application-field-emitter01925nas a2200193 4500008004100000022001400041245009300055210006900148260007300217300001200290490000800302520119600310653002101506653002101527653002301548653001501571100002401586856012101610 2016 eng d a1387-181100aLiquid exfoliation of black phosphorus nanosheets and its application as humidity sensor0 aLiquid exfoliation of black phosphorus nanosheets and its applic aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a494-5030 v2253 a

The bulk crystal of black phosphorus was exfoliated by liquid exfoliation method for a duration of 8 h using N-Methyl-2-Pyrrolidone as the solvent. The exfoliated sample was centrifuged at different rpm such as 3000, 5000 and 10,000 to separate out the 2D black phosphorus nanosheets with different thickness and length. The as synthesized black phosphorus nanosheets collected at these rpm values were characterized with TEM, AFM, Raman spectroscopy and Vis-NIR spectroscopy. Further, we investigated the humidity sensing behaviour of the devices fabricated by using these samples. The results obtained show that the device fabricated with black phosphorus nanosheets and nanoparticles obtained by filtration of the sample collected after 10,000 rpm exhibited better performance as compared to the nanosheets collected at 3000 and 5000 rpm. The response and recovery times of devices are found to be promising and better than those of the black phosphorus gas sensor reported earlier. The present investigations open up a new avenue for further studies in improving the performance of black phosphorus nanosheets based gas sensing devices. (C) 2016 Elsevier Inc. All rights reserved.

10ablack phosphorus10aHumidity sensors10aLiquid exfoliation10ananosheets1 aLate, Dattatray, J. uhttp://library.ncl.res.in/content/liquid-exfoliation-black-phosphorus-nanosheets-and-its-application-humidity-sensor02444nas a2200217 4500008004100000022001400041245009300055210006900148260011000217300001400327490000600341520159700347100002801944700002001972700002401992700001802016700002302034700002402057700002102081856012402102 2016 eng d a2050-752600aLow frequency noise and photo-enhanced field emission from ultrathin PbBi2Se4 nanosheets0 aLow frequency noise and photoenhanced field emission from ultrat aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcDEC a1096-11030 v43 a

Atomically thin two-dimensional layered materials have gained wide interest owing to their novel properties and potential for applications in nanoelectronic and optoelectronic devices. Here, we present the spectral analysis and photo-enhanced field emission studies of a layered intergrowth PbBi2Se4 nanosheet emitter, performed at the base pressure of similar to 1 x 10(-8) mbar. The emitter shows a turn-on field value of similar to 4.80 V mu m(-1), corresponding to an emission current density of similar to 1 mu A cm(-2). Interestingly, when the cathode was illuminated with visible light, it exhibited a lower turn-on field of B3.90 V mm(-1), and a maximum emission current density of similar to 893 mu A cm(-2) has been drawn at an applied electric field of similar to 8.40 V mu m(-1). Furthermore, the photo-enhanced emission current showed reproducible, step-like switching behavior in synchronous with ON-OFF switching of the illumination source. The emission current-time plots reveal excellent stability over a duration of similar to 6 h. Low-frequency noise is a significant limitation for the performance of nanoscale electronic devices. The spectral analysis performed on a Fast Fourier Transform (FFT) analyzer revealed that the observed noise is of 1/f(alpha) type, with the value of alpha similar to 0.99. The low frequency noise, photo-enhanced field emission, and reproducible switching behavior characterized with very fast rise and fall times propose the layered PbBi2Se4 nanosheet emitter as a new promising candidate for novel vacuum nano-optoelectronic devices.

1 aSuryawanshi, Sachin, R.1 aGuin, Satya, N.1 aChatterjee, Arindom1 aKashid, Vikas1 aMore, Mahendra, A.1 aLate, Dattatray, J.1 aBiswas, Kanishka uhttp://library.ncl.res.in/content/low-frequency-noise-and-photo-enhanced-field-emission-ultrathin-pbbi2se4-nanosheets-001341nas a2200193 4500008004100000245009000041210006900131260000800200300001400208490000800222520066200230100002200892700002000914700002600934700002400960700002300984700002501007856011501032 2016 eng d00aLow turn-on field and high field emission current density from Ag/TiO 2 nanocomposite0 aLow turnon field and high field emission current density from Ag cJUL a167–1710 v6573 a

High current density of 1.24 mA/cm2 was drawn at an applied field of 4.4 V/μm from Ag/TiO2 nanocomposite. Also the turn-on field has been reduced from 3.9 V/μm to 2.7 V/μm for the emission current density of 10 μA/cm2. Ag/TiO2 nanocomposite was synthesized by using UV-switchable reducing agent. TiO2 nanotube wall was decorated by Ag nanoparticles with average diameter of 17 nm. To the best of our knowledge this is the first report on the field emission studies of Ag/TiO2 nanocomposite. Simple synthesis route coupled with superior field emission properties indicate the possible use of Ag/TiO2 nanocomposite for micro/nanoelectronic devices.

1 aPatil, Girish, P.1 aDeore, Amol, B.1 aBagal, Vivekanand, S.1 aLate, Dattatray, J.1 aMore, Mahendra, A.1 aChavan, Padmakar, G. uhttp://library.ncl.res.in/content/low-turn-field-and-high-field-emission-current-density-agtio-2-nanocomposite