Investigations of Vacancy-Assisted Selective Detection of NO Molecules in Vertically Aligned SnS.

Two important methods for enhancing gas sensing performance are vacancy/defect and interlayer engineering. Tin sulfide (SnS) has recently attracted much attention for sensing of the NO gas due to its active surface sites and tunable electronic structure. Herein, SnS has been synthesized by the chemical vapor deposition (CVD) method followed by nitrogen plasma treatment with different exposure times for fast detection of NO molecules.

Platinum nanoparticle sensitized plasmonic-enhanced broad spectral photodetection in large area vertical-aligned MoSflakes.

2D MoSholds immense potential for electronic and optoelectronic applications due to its unique characteristics. However, the atomic-scale thickness of MoShinders the optical absorbance, thereby limiting its photodetection capability. Vertically-aligned MoS(VA-MoS) has an advantage of strong optical absorption and quick intra-layer transport, offering high speed operation.

Davydov Splitting, Resonance Effect and Phonon Dynamics in Chemical Vapor Deposition Grown Layered MoS.

We present comprehensive temperature dependent Raman measurements for chemical vapor deposition grown horizontally aligned layered MoSin a temperature range of 4-330 K under a resonance condition. Our analysis of temperature dependent phonon frequency shift and linewidth suggests a finite role of three and four phonon anharmonic effect. We observe Davydov splitting of the out-of-plane () and in-plane (E2g1) modes for both three layer (3L) and few layer (FL) systems.

Anisotropic electron-photon-phonon coupling in layered MoS.

Transition metal dichalcogenide, MoShas attracted a lot of attention recently owing to its tunable visible range band gap, and anisotropic electronic and transport properties. Here, we report comprehensive inelastic light scattering measurements on both chemical vapor deposition grown (horizontally and vertically aligned) flakes, and mechanically exfoliated flakes of single crystal MoS. We probe the anisotropic optical response by studying the polarization dependence intensity of the Raman active phonon modes as a function of different incident photon energy and flake thickness.

Thermal expansion coefficient and phonon dynamics in coexisting allotropes of monolayer WS probed by Raman scattering.

We report a comprehensive temperature dependent Raman measurement on three different phases of monolayer WS from 4 K to 330 K in a wide spectral range. Our studies reveal the anomalous nature of the first, as well as the higher order combination modes reflected in the disappearance of the few modes and anomalous temperature evaluation of the phonon self-energy parameters attributed to the detuning of resonance condition and development of strain due to thermal expansion mismatch with the underlying substrate. Our detailed temperature dependence studies also decipher the ambiguity about the assignment of the two modes in literature near ~297 cm and 325 cm.

Correlated paramagnetism and interplay of magnetic and phononic degrees of freedom in 3d-5d coupled LaCuIrO.

Conventional paramagnetism-a state with finite magnetic moment per ion sans long range magnetic ordering, but with lowering temperature the moment each ion picks up a particular direction, breaking spin rotational symmetry, and results into long-range magnetic ordering. However, in systems with competing multiple degrees of freedom this conventional notion may easily break and results into short range correlation much above the global magnetic transition temperature. LaCuIrO with complex interplay of spins (s  =  1/2) on Cu site and pseudo-spin (j   =  1/2) on Ir site owing to strong spin-orbit coupling provides fertile ground to observe such correlated phenomena.

Enhanced upconversion quantum yield near spherical gold nanoparticles - a comprehensive simulation based analysis.

Photon upconversion is promising for many applications. However, the potential of lanthanide doped upconverter materials is typically limited by low absorption coefficients and low upconversion quantum yields (UCQY) under practical irradiance of the excitation. Modifying the photonic environment can strongly enhance the spontaneous emission and therefore also the upconversion luminescence.