Dr. Shashikant Rajpal
@nifft.ac.in
National Institute of Foundry and Forge Technology, Ranchi
Scopus Publications
Scopus Publications
Suresh Kumar, Shashikant Rajpal, S. K. Sharma, and S. R. Kumar
AIP Publishing
Sudeshna Surabhi, KumarAnurag, Shashikant Rajpal, and S.R Kumar
Elsevier BV
Abstract 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.
Shashikant Rajpal and S.R. Kumar
Elsevier BV
Abstract 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.
Shashikant Rajpal and S.R. Kumar
Elsevier BV
Abstract 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.
Shashikant Rajpal and S.R. Kumar
Elsevier BV
Abstract 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.