Browsing by Author "Trivedi, Harshita"

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    Investigating optical, structural and morphological properties of polycrystalline CdTe thin-film deposited by RF magnetron sputtering
    (Elsevier B.V., 2021) Trivedi, Harshita; Gaganpreet; Boochani, Arash; Shagya, Naresh; Lahiri, Jayeeta; Ghorannevis, Zohreh; Parmar, Avanish S.
    In this work, optimization of the physical properties of cadmium telluride (CdTe) thin films has been carried out to improve its performance by the influence of RF power. CdTe Nanocrystalline thin films were characterized by using various techniques such as atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). XRD study revealed that CdTe films are polycrystalline and have preferential growth in (1 1 1) direction. FESEM images showed a continuous and dense morphology of CdTe films on glass substrates. The AFM result shows that the surface roughness of films increases with annealing. Optical properties were investigated with the help of the UV�visible absorption spectrum which showed that the bandgap decreases with an increase in Radio-frequency power. Further, density functional theory (DFT) calculations showed that the optimum bandgap i.e. 1.57 eV for CdTe films deposited at 100 W RF power with 2% N2 is in good agreement with the experimental result. This study showed that CdTe films deposited at 100 W RF power with 2% N2 can be used as an excellent absorbing material for the application of optoelectronic devices solar cells. � 2021 The Author(s)
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    Investigation of dielectric and optical properties of pure and diamond nanoparticles dispersed nematic liquid-crystal PCH5
    (Taylor and Francis Ltd., 2021) Gaur, Dhananjay Kumar; Rastogi, Ayushi; Trivedi, Harshita; Parmar, Avanish Singh; Manohar, Rajiv; Singh, Shri
    In the present work, we have dispersed diamond nanoparticles (DNPs) in nematic liquid crystal 4-(Trans-4?-n-Pentylcyclohexyl) Benzonitrile (PCH5) and studied the dielectric and optical properties of pure and DNPs dispersed nematic systems. We have investigated the effect of dispersion of DNPs (concentrations 0.5 and 1.0�wt%) in nematic liquid crystals (NLC) PCH5 on the dielectric permittivity, dielectric loss, dielectric anisotropy, photoluminescence, UV-Vis absorbance. It has been found that these properties are influenced by the dispersion of DNPs in nematic PCH5 system and applied electric field. Due to the dispersion of DNPs (1.0�wt% concentration) in PCH5, a significant decrease in the relative permittivity occurs. The relaxation peaks of dielectric loss shifts towards higher frequency side for NLC-DNPs composites. The dielectric anisotropy has been found to decrease with the dispersion of DNPs into pure NLC. The PL emission and UV-Vis absorbance for the dispersed systems have been decreased. An effort has been made to explain the observed results on the basis of interaction between nematic molecules and diamond NPs. The possible applications have also been suggested for the dispersed systems in this study. � 2020 Informa UK Limited, trading as Taylor & Francis Group.
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    Synthesis and physical characterization of magnetron sputtered Graphene-CdS bilayer
    (IOP Publishing Ltd, 2021) Trivedi, Harshita; Shafaghi, Hanieh; Shagya, Naresh; Lahiri, Jayeeta; Ghorannevis, Zohreh; Parmar, Avanish S
    CdS/Graphene Nano composites have been extetinsively investigated in the field of basic industrial research and electronic device applications because of their unique physical, chemical properties and photo stability under visible-light irradiation. In this study, we explore the electrical properties of Cadmium sulfide with the addition of graphene. CdS/Graphene hybrid was fabricated by simple RF magnetron sputtering method using CdS as a sputtering source. The hybrid material formation and structural properties of Graphene, CdS, CdS/Graphene have been discussed using XRD, FTIR, Raman, and UV-vis spectroscopy techniques. Herein, we present a facile and efficient method for hybridization of CdS Nano-sphere with graphene Nano sheet and subsequent investigation of enhancement of current of the hybrid material. Field emission scanning electron microscopy (FESEM) micrographs reveal the formation of CdS nanospheres and homogeneous scattering on the surface of graphene sheets. The UV absorption spectrum of CdS/Graphene hybrid presented a red-shifted. The enhancement in the current of CdS/Graphene hybrid has been observed due to the generation of electron-hole pairs. Also, current-voltage (I-V) characteristics of an as-grown thin film of the hybrid are conducted using 4-point probe measurement and revealed their semiconducting nature with a drastic enhancement of electrical conductivity. � 2021 The Author(s). Published by IOP Publishing Ltd.