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The thermal oxidation process of the indium nitride (InN) nanorods (NRs) was studied. The SEM studies reveal that the cracked and burst mechanism for the formation of indium oxide (In2O3) nanostructures by oxidizing the InN NRs at higher temperatures. XRD results confirm the bcc crystal structure of the as prepared In2O3 nanostructures. Strong and broad photoluminescence spectrum located at the green to red region with maximum intensity at 566 nm along with a weak ultraviolet emission at 338 nm were observed due to oxygen vacancy levels and free excitonic transitions, respectively. The valence band onset energy of 2.1 eV was observed from the XPS valence band spectrum, clearly justifies the alignment of Fermi level to the donor level created due to the presence of oxygen vacancies which were observed in the PL spectrum. The elemental ratio In:O in as prepared In2O3 was found to be 42:58 which is in close agreement with the stoichiometric value of 40:60. A downward shift was observed in the Raman peak positions due to a possible phonon confinement effect in the nanoparticles formed in bursting mechanism. Such single junction devices exhibit promising photovoltaic performance with fill factor and conversion efficiency of 21% and 0.2%, respectively, under concentrated AM1.5 illumination.

Well uniform microspheres of phase pure Covellite were synthesized through a simple hydrothermal approach using poly vinyl pyrrolidone (PVP) as surfactant. The micro-spheres were constituted of numerous self-organized knitted nano-ribbons of ∼ 30 nm thickness. The effect of conc. PVP in the hydrothermal precursor solution on the product morphology was investigated. Based on the out-coming product micro-architecture a growth mechanism was proposed which emphasized bubbled nucleation inside the hydrothermal reactor. In a comparative study on linear optical properties, enhancement of luminescent intensity was observed for nano-ribbon clung microspheres rather than that of agglomerates of distorted particles, which may be attributed to better crystallinity as well as reduced surface defects and ionic vacancies for ribbon-like nano-structures.

This paper reports an experimental study on the synthesis and structural characterization of lead zirconate, PbZrO3, (PZ) nanotubes fabricated by an improved sol-gel method within the nanochannels of anodic aluminum oxide (AAO) templates. The morphology, structure, and composition of the nanotubes were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), selected-area electron diffraction (SAED), high resolution TEM (HRTEM) and energy-dispersive X-ray spectroscopy (EDX). The results of XRD and SAED indicated that postannealed (700 degrees C for 1 h) PZ nanotubes had an orthorhombic distorted perovskite polycrystalline crystal. SEM and TEM analysis revealed that PZ nanotubes possessed a uniform length and diameter, which were controlled by the thickness and the pore diameter of the applied AAO template, respectively and the thickness of the wall of the PZ nanotubes was about 15 nm. Y-junctions were also observed in the PZ nanotubes. EDX analysis demonstrated that stoichiometric PbZrO3 was formed. HRTEM image and a typical SEM image confirmed that the obtained PZ nanotubes composed of nanoparticles in the range of 4-8 nm. The possible formation mechanism of nanotubes was discussed.