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Pyrolized Growth of (Al, N) Dual Doped CdO Thin Films and Study of Structural, Surface Morphology and Opto-Electrical Properties
A. F. M. Faizullah,
M. K. R. Khan,
M. Mozibur Rahman
Issue:
Volume 2, Issue 4, July 2013
Pages:
124-127
Received:
19 June 2013
Published:
20 July 2013
Abstract: Thin films of undoped and (Al, N) dual doped CdO were prepared on glass substrate at substrate temperature 350 ºC by spray pyrolysis method. The films are characterized by XRD, AFM, Optical and electrical properties. The films are highly poly crystalline and found to be cubic. AFM images show the surface properties of the film. It increases with increasing concentration of Al & N in the CdO samples. Optical transmittance is made at room temperature within the wavelength range 400 nm to 1100 nm. Direct band gap of undoped CdO has been measured and found to be 2.58 eV and it decreases with (Al, N) dual doping in CdO thin film upto 2.52 eV. The resistivity of undoped CdO shows the metallic behavior upto 370 K and then followed by semiconducting behavior. (Al, N) dual doping shows the carrier compensation during temperature range (355 - 375) K.
Abstract: Thin films of undoped and (Al, N) dual doped CdO were prepared on glass substrate at substrate temperature 350 ºC by spray pyrolysis method. The films are characterized by XRD, AFM, Optical and electrical properties. The films are highly poly crystalline and found to be cubic. AFM images show the surface properties of the film. It increases with i...
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Metal-Insulator Phase Transition and Structural Stability in ‘Sb’ Doped CaMnO3 Perovskite
R. Kannan,
D. Vanidha,
A. Arun Kumar,
K. U. Rama Tulasi,
R. Sivakumar
Issue:
Volume 2, Issue 4, July 2013
Pages:
128-135
Received:
19 June 2013
Published:
20 July 2013
Abstract: Electron doped Ca1-xSbx MnO3 (X = 0 to 0.4) compound when prepared by high temperature solid state reaction, exhibits orthorhombic distorted perovskite structure. A systematic, continuous doping increases the metal – insulator transition temperature to above the room temperature (≈431 to 469 K); due to the mismatch of ionic radii in A site rising anti - site effect, which consequently changes the bond length. Doping induced metal – insulator transition accompanied by structural transition is reflected through the drastic changes in the parameters like cation size variance factor (), average ionic radius , tolerance factor (t) and To-which is correlated to the band related transport properties. Structural transition from the phase of perovskite to Brownmillerite has been found for the compositions x = 0.3 and 0.4, which is attributed due to the ionic radii mismatch. Doping exerts chemical pressure by modifying compression of A-O bond and relaxation of B-O bond, giving rise to strain similar to external pressure in ABO3 perovskite. The dependence of electrical transport at high temperature has been studied, by employing variable range hopping and small polaron hopping model as an account for the experimental observation due to disorder induced localization.
Abstract: Electron doped Ca1-xSbx MnO3 (X = 0 to 0.4) compound when prepared by high temperature solid state reaction, exhibits orthorhombic distorted perovskite structure. A systematic, continuous doping increases the metal – insulator transition temperature to above the room temperature (≈431 to 469 K); due to the mismatch of ionic radii in A site rising a...
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Synthesis and Structural Studies of Nickel Complex Supported by-ONNO-Tetra Dentate Schiff-Base Ligand: Efficient Catalysts for Oxidation of Phenol
Alekha Kumar Sutar,
Yasobanta Das,
Sasmita Pattnaik,
Nibedita Nath,
Prasanta Rath,
Tungabidya Maharana
Issue:
Volume 2, Issue 4, July 2013
Pages:
136-145
Received:
2 July 2013
Published:
10 August 2013
Abstract: The free and polymer anchored complex of nickel [3-MHBdMBn-Ni and P-3-MHBdMBn-Ni], supported by -ONNO-tetradentate Schiff-base ligand are prepared by the reactions of nickel solution with one molar equivalent of unsupported 3-MHBdMBn (N, N'-bis (2-hydroxy-3-methylbenzaldehyde) 4-Methylbenzene-1,2-diamine) or polymer supported (P-3-MHBdMBn) Schiff-base ligands in methanol. The structural study reveal that nickel (II) complex of 3-MHBdMBn Schiff base is square planar in geometry. Complexation of nickel ion increased the thermal stability of 3-MHBdMBn Schiff base. The catalytic activity of nickel complex towards the oxidation of phenol is investigated in the presence of hydrogen peroxide. Experimental results indicate that the reactivity of P-3-MHBdMBn-Ni is dramatically affected by the polymer support over 3-MHBdMBn-Ni and the rate of oxidation (Rp) for unsupported one is 1.28 x 10-6 mole dm-3 s-1 and for supported analogue is 1.99 x 10-6 mole dm-3 s-1.
Abstract: The free and polymer anchored complex of nickel [3-MHBdMBn-Ni and P-3-MHBdMBn-Ni], supported by -ONNO-tetradentate Schiff-base ligand are prepared by the reactions of nickel solution with one molar equivalent of unsupported 3-MHBdMBn (N, N'-bis (2-hydroxy-3-methylbenzaldehyde) 4-Methylbenzene-1,2-diamine) or polymer supported (P-3-MHBdMBn) Schiff-b...
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