Morphological And Impedance Studies In Diluted Mn-doped CdS Nanocomposites
P. Venkatesu, K. Ravichandran, B. K. Reddy
Volume 4, Issue 10, Page 786-791 | DOI: 10.5185/amlett.2013.2429
Keywords: CdS: Mn; phase transition; blue shift; cole-cole plots.
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. Copyright © 2013 VBRI press.