arXiv subjects

Kulwinder Singh

Publications and source records attributed to Kulwinder Singh.

3 recordsLinked to original sources

arXiv2020

Low temperature carrier transport mechanism and photoconductivity of WSe2

This work reports the electrical transport and temperature-dependent photoconductivity in tungsten diselenide (WSe2) thin films. The electrical conductivity analysis shows the presence of the three regions with temperature variation. At lower temperatures (<190K), carriers become localized to small regions in the film due to the Mott hopping mechanism. The middle region (190 to 273 K) follows Seto parameters and obtained low barrier height (0.0873 eV) may be responsible for the improved carrier mobility. At higher temperature (>273K) region, thermally activated conduction is dominated with two activation energies of ~138 meV and 98 meV. The peaks obtained in photoluminescent analysis attributes to the presence of mid-bandgap states or defect states which play an important role in the photoconductivity of WSe2. The transient photoconductivity measurements show consistent temperature-dependent behaviour. The effect of light intensity and wavelength variation on the photoconductivity of WSe2 thin films is also discussed. The photocurrent is 1.19*10-5 A at 125 K while at 350 K it was observed to be 3.12*10-4 A. The light-on/off current cycles show that the current can recover to its initial state which points to the stable and outstanding reversible properties of the WSe2 thin film device to be used in photodetector applications.

cond-mat.mtrl-sci↗

arXiv2019

Insights of preferred growth, elemental and morphological properties of BN/SnO2 composite for photocatalytic applications towards organic pollutants

Boron nitride (BN) has been explored these days because of its extraordinary optical, chemical and mechanical properties. BN is sensitive to its crystal structure that slight change in lattice parameters enormously change its properties. Present study deals with synthesis, characterization as well as photocatalytic applications of BN-based composite. When boron nitride was mixed with SnO2 having tetragonal crystal structure, dissociation into smaller sheets occurred and the material oriented to (102) plane. SnO2 particles attached both sides of BN sheets provided high surface area which make the material suitable for catalytic process. Presence of large number of active sites leads to the formation of hydroxyl radicals in BN/SnO2 composite which helps during degradation of organic and colourless pollutants i.e. methyl orange dye up-to ~92% under 7 minutes and salicylic acid in 40 minutes to ~82%. Results suggested that BN/SnO2 composite material possesses good capability for use in environmental as well as industrial applications.

cond-mat.mtrl-sci↗

arXiv2017

Specially designed B4C/SnO2 nanocomposite for photocatalysis: traditional ceramic with unique properties

Boron carbide: A traditional ceramic material shows unique properties when explored in nano-range. Specially designed boron based nanocomposite has been synthesized by reflux method. The addition of SnO2 in base matrix increase the defect states in boron carbide and shows unique catalytic properties. The calculated texture coefficient and Nelson Riley factor shows that the synthesized nanocomposite have very high defect states. Also this composite is explored for the first time for catalysis degradation of industrial used dyes. The industrial pollutants such as Novacron red and methylene blue dye degradation analysis reveal that the composite is an efficient catalyst. Degradation study shows that 1 g/L catalyst concentration of B4C/SnO2 degrade Novacron red Huntsman dye upto 97.38% approximately in 20 minutes under sunlight irradiation time. This water insoluble catalyst can be recovered and reused.

physics.app-ph↗