Enhanced photoanode properties of epitaxial Ti doped α-Fe2O3 (0001) thin films Appl. Phys. Lett. 101, 133908 (2012) Roto-flexoelectric coupling impact on the phase diagrams and pyroelectricity of thin SrTiO3 films J. Appl. Phys. 112, 064111 (2012) Plasmonic effects of ultra-thin Mo films on hydrogenated amorphous Si photovoltaic cellsHighly crystalline c-axis oriented and homogeneous ZnO 1Àx S x films with sulfur composition 0.05 x 0.9 without phase separation were deposited using spray pyrolysis of aqueous precursors. A mechanism of film growth is proposed which envisages a slower kinetics of ZnO precursor decomposition and its specific by-products combined with S-precursor decomposition which enables homogeneous ZnO 1Àx S x phase formation over a wide S-composition range 0.05 x 0.9. This is achieved by controlling the substrate temperature to 300 C and the spray rate at $ 3 ml/min. The ZnO 1Àx S x films primarily form by S 2À substitution at the O 2À lattice sites which is confirmed by detailed analysis of the Zn2p, S2p and O1s x-ray photoelectron spectroscopy peaks. With the increasing of S-content, a structural transformation is observed in ZnO 1Àx S x films; for x < 0.3, the ZnO 1Àx S x films in the oxygen-rich phase are in ZnO wurtzite crystal structure and for x ! 0.44, the ZnO 1Àx S x films lie in the sulfur-rich phase with b-ZnS structure. At threshold x ¼ 0.3, in the structural transition state, diffraction peaks corresponding to both structural phases are observed. The optical transmission spectra at the band gap transition energy position shift to the red side for 0.05 x < 0.52 and towards the blue side with the further increase in S-content in the 0.52 < x 0.9 range. Optical band gap energy determined for ZnO 1Àx S x films show strong band gap bowing over the entire S-composition range, 0.05 x 0.9. The band gap modulation with increased S-content is inconsistent with the use of a single bowing parameter. A bowing parameter of 2.5 eV shows a closer fit for 0.05 x < 0.52. By accounting for additional effect of the strain energy on the band gap due to addition of excess S-content, a closer fit for the observed variation in the band gap is explained in the 0.52 < x 0.9 composition range. Electrical resistivity variation with S-content is consistent with the compensating effect of S 2À substitution at the O 2À sites in ZnO 1Àx S x films. V C 2012 American Institute of Physics.

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Ordered one dimensional polypyrrole conducting polymer structure as a shell over TiO2 nanotube arrays at the core were formed by pulsed current electropolymerization. TiO2 nanotubes with rippled wall structure are designed by action of water in the anodizing medium. This provides open tube structure supporting short diffusion length and increased accessibility of ions involved in redox transition for energy storage. Electrochemical properties evaluated by cyclic voltammetry and electrochemical impedance spectroscopy show specific capacitance of 34-44 mF.cm-2 and extremely low bulk and charge transfer resistances.

The Cu and Mn co-doped ZnO dilute magnetic semiconductor Zn x O films with unique nanoneedle like structure were deposited at ≤300 • C by a two step closed space flux sublimation and periodic oxidation method. Morphology studies establish complex growth process involving a eutectic metal condensate on the substrate and spontaneous emergence of nanoneedle structure by oxidative process controlled by the vapor-liquid-solid mechanism. X-ray diffraction studies show that Zn 1-x (Cu-Mn) x O films retain the typical wurtzite hcp structure of the un-doped ZnO. The absence of extraneous reflections indicates that neither the Mn and Cu dopant metal clusters nor their oxide phases are included in the nanostructure Zn 1-x (Cu-Mn) x O films. The Raman peaks of Zn 1-x (Cu-Mn) x O nanocrystalline films are consistent with the Raman active phonon modes for ZnO. The red shifted E 2 (Low) and E 2 (high) peaks confirm that Mn and Cu substitute at Zn site in the nanostructure Zn 1-x (Cu-Mn) x O films. Optical transition at direct band gap energy occurs at 3.11 eV and an upward energy shift in the direct band to 3.58 eV is assigned to the quantum size effects of the nanoneedle structure of Zn 1-x (Cu-Mn) x O films.