Ramakanta Naik
Abstract
The present paper highlights the optical properties change in thermally evaporated As40Sb15Se45 amorphous film of 800 nm thickness with laser irradiation. The as-prepared and illuminated films were studied by X-ray diffraction, Energy dispersive X-ray analysis. The optical properties were calculated ...
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The present paper highlights the optical properties change in thermally evaporated As40Sb15Se45 amorphous film of 800 nm thickness with laser irradiation. The as-prepared and illuminated films were studied by X-ray diffraction, Energy dispersive X-ray analysis. The optical properties were calculated from the transmission spectra obtained from Fourier Transform Infrared Spectroscopy. The band gap is decreased by 0.22 eV due to photo induced effects causing photo darkening. The refractive index is found to be increased due to increase in structural disordering. These optical properties changes are due to the change of homopolar bond densities which can be seen from the core level peak shifting in XPS spectra. The optical constants such as refractive index, band gap of the material plays a major role in the preparation of the device for a particular wavelength. Selecting suitable pairs of chalcogenide glasses with different optical gaps, one can modify the parameters of the light sensitive layers and use them for optical recording.
P. Venkatesu; K. Ravichandran; B. K. Reddy
Abstract
Nanocrystalline samples of Cadmium Sulphide (CdS) were prepared with different Manganese (Mn) doping concentrations (0-10 at.%) through chemical route using thiophenol as a capping agent. Fourier Tranform Infrared Spectroscopy (FT-IR) study disclosed the presence of capping agent on the surface of the ...
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Nanocrystalline samples of Cadmium Sulphide (CdS) were prepared with different Manganese (Mn) doping concentrations (0-10 at.%) through chemical route using thiophenol as a capping agent. Fourier Tranform Infrared Spectroscopy (FT-IR) study disclosed the presence of capping agent on the surface of the samples. X-ray diffraction (XRD) analysis showed phase transition from hexagonal to cubic phase beyond 8 at.% of Mn doping and grain size in the range of 13-30 nm. Micro structural study by High Resolution Transmission Electron Microscopy (HRTEM) confirmed phase transition and quasi-spherical particles having size in 15-50 nm range with small grains distributed on the surface of the particles. A blue shift in the band gap energy of the samples was indicated in optical absorption study and the band gap was found to vary nonlinearly with Mn content. Studies on electrical properties of the samples using a complex impedance spectroscopy (CIS) technique showed a decrease in the bulk resistance with increase in Mn concentration. Further, the nature of cole-cole plots (Nyquist plots) revealed the presence of bulk and grain boundary effects in the samples in consistent with HRTEM results. These crystalline quasi-spherical nanoparticles of CdS:Mn seems to be one of the promising candidates for modern age opto-electronics and biomedical applications.
