Dr. Shashikant Rajpal

@nifft.ac.in

National Institute of Foundry and Forge Technology, Ranchi

10

Scopus Publications

Scopus Publications

  • Structural, morphological and optical studies of chemically developed annealed Cu doped CdS nanofilms
    Journal of Optoelectronics and Advanced Materials, 2024
  • Studies on the effects of annealing on the structural and optical properties of nanocrystalline ZnCdS thin films
    Chalcogenide Letters, 2022
  • Influence of annealing on ZnCdS thin films: Structural and optical properties
    Suresh Kumar, Shashikant Rajpal, S. K. Sharma, S. R. Kumar
    Aip Conference Proceedings, 2021
    Zinc cadmium sulphide (ZnCdS) is one of the important II-VI compound semiconductors. It has direct band gap semiconductor material having wide applications such as photovoltaic solar cell, photoconductor, window material in several hetero-junction device solar cells, etc. The present works reports upon ZnCdS films with various annealing temperature have been carried out in non-aqueous medium by chemical bath deposition (CBD) method using cadmium chloride, zinc chloride and thiourea as precursors dissolved with ethylene glycol. The study of structural, morphological and optical properties was done by X-ray Diffraction (XRD), Field emission scanning electron microscopy (FESEM), UV-Visible spectroscopy and Photoluminescence (PL). The crystal structure and surface morphology of various annealing temperature for ZnCdS films have been studied by X-ray diffraction and Field emission scanning electron microscope. XRD spectra give information that varying annealed temperature ZnCdS films exhibited peaks corresponds to (100), (002), (101), (102) and (103) respectively and the appearance of (002) diffraction peak indicates that the films have hexagonal structure. Crystallite size of the said films was calculated with the help of Debye-Scherrer formula and was found to be 23 nm, 25 nm and 26 nm. The calculated bandgap of annealed films at 350°C, 400°C and 450°C are to be 2.66 eV, 2.75 eV and 2.70 eV.
  • A new route for preparing CdTe thin films by chemical bath deposition
    Sudeshna Surabhi, KumarAnurag, Shashikant Rajpal, S.R Kumar
    Materials Today Proceedings, 2021
    Cadmium telluride (CdTe) is a binary II-VI direct band gap semiconducting material. Cadmium telluride is a promising electrochemical and photovoltaic material for thin film solar cells. It shows both p and n type conductivity. A nanocrystalline thin film of CdTe was deposited in homogeneous medium on nickel plate by chemical bath deposition method containing 0.01 M cadmium acetate and 0.02 M tellurium dioxide. The structural, compositional and optical analysis were studied by x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDS), scanning electron microscope (SEM), Fourier Transform infrared spectroscopy (FTIR) and Photoluminescence (PL).The diffraction peak observed at 2θ = 23.59° with (1 1 1) plane indicate the crystalline phase of CdTe film. The average crystalline size is measured to be 7 nm. Compositional analysis reveals the presence of both Cd and Te elements. The EDS Spectroscopy shows the ratio of Cd and Te is1:2 in case of as deposited film. The Photoluminescence peak is observed at 471 nm.
  • Annealing temperature dependent structural and optical properties of nanocrystalline ZnTe thin films developed by electrodeposition technique
    Shashikant Rajpal, S.R. Kumar
    Solid State Sciences, 2020
    ZnTe is a potential material for device fabrication because of the suitable optoelectronic properties. In this work, a nanocrystalline binary semiconductor zinc telluride (ZnTe) was developed in non-aqueous medium through an electrochemical deposition process. We report the structural and optical properties of developed ZnTe films deposited on nickel and glass substrate at various temperatures (350–500 °C). The solid state and optical properties of developed film was characterized by XRD, SEM, EDS, UV Vis spectroscopy and Photoluminescence spectroscopy. XRD analysis indicates the polycrystalline deposits in all the cases. The sharpness of the peak increases due to annealing of the film and average crystalline size increases. SEM photograph indicate that grains are uniform and densely distributed over the surface. The main effect of annealing temperature was helpful to improve crystalline structure, whereas the bandgap of semiconductor was reduced due to large density of dislocations. This study is vital for the optimization of the annealing temperature for growth of good-quality ZnTe films, which are necessary for device fabrication and applications.
  • Influence of annealing on structural and optical properties of cds thin films developed by chemical route
    Journal of Ovonic Research, 2018
  • Thermoluminescent properties of nanocrystalline ZnTe thin films: Structural and morphological studies
    Shashikant Rajpal, S.R. Kumar
    Physica B Condensed Matter, 2018
    Zinc Telluride (ZnTe) is a binary II-VI direct band gap semiconducting material with cubic structure and having potential applications in different opto-electronic devices. Here we investigated the effects of annealing on the thermoluminescence (TL) of ZnTe thin films. A nanocrystalline ZnTe thin film was successfully electrodeposited on nickel substrate and the effect of annealing on structural, morphological, and optical properties were studied. The TL emission spectrum of as deposited sample is weakly emissive in UV region at ∼328 nm. The variation in the annealing temperature results into sharp increase in emission intensity at ∼328 nm along with appearance of a new peak at ∼437 nm in visible region. Thus, the deposited nanocrystalline ZnTe thin films exhibited excellent thermoluminescent properties upon annealing. Furthermore, the influence of annealing (annealed at 400 °C) on the solid state of ZnTe were also studied by XRD, SEM, EDS, AFM. It is observed that ZnTe thin film annealed at 400 °C after deposition provide a smooth and flat texture suited for optoelectronic applications.
  • Effect of Zn concentration on the structural, morphological and optical properties of ternary ZnCdS nanocrystalline thin films
    Digest Journal of Nanomaterials and Biostructures, 2017
  • Effect of Annealing on Nano crystalline ZnO Thin Film Developed by Electro deposition Method
    Shashikant Rajpal, S.R. Kumar
    Materials Today Proceedings, 2017
    ZnO is a II–VI compound semiconductor with wide bang gap and hexagonal wurtzite structure. Zinc oxide films were deposited by electrodeposition technique, containing very low concentrations of sodium citrate and hydrogen peroxide. Ammonium hydroxide were added to control the reaction. The as deposited films were annealed in air at 400°C The analysis were initially studied with X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and Optical properties. The average grain size is measured to be 48nm.The grains are spherical, well connected and uniformly distributed. The energy band gap is found to be 3.35 eV in as deposited case and 3.23 eV in annealed case.
  • Effect of annealing on the surface and optical properties of ZnCdS nanocrystalline thin films
    Chalcogenide Letters, 2017