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It is generally accepted that the nonlinear I–V characteristics for semiconductor nanostructures are mainly induced by the Schottky contacts or by the space charge limited transport mechanism. We perform I–V measurements on undoped and doped In–Zn–O compound nanobelts and confirm that their intrinsic non-ohmic transport behaviors are not caused by these mechanisms. A model based on the hopping assisted trap state electrons transport process is introduced to explain the nonlinear I–V characteristics and to extract their electrical parameters. An understanding of this trap-state influenced carrier transport can advance the progress of nanomaterials applications and enable us to distinguish their intrinsic transport behaviors from contact effects. The results also indicate that the material has good electrical properties and can be used as a potential substitute for In2O3. [ABSTRACT FROM AUTHOR]

Highly aligned nanowire bundles were controllably fabricated through the reaction of Si with oxygen, using molten Ga and Au as catalysts. Scanning electron microscopy reveals that the bundles have the ability to self-assemble into various morphologies, a few of which, including one that strikingly resembles a sunflower, were not reported before. Examinations of the bundles by transmission electron microscopy show that they contain fine, amorphous SiOx nanowires, with x ranging from 1.2 to 1.5. In the sunflower-like morphology, highly packed bundles form the disc florets and loosely packed bundles around the rim of the disc form the ray florets. We have studied the conditions under which the sunflower-like morphology could be obtained and suggest a possible mechanism for its growth. Room-temperature cathodoluminescence spectra of the nanowire bundles show that they emit an intense broad-band light covering the entire visible range. [ABSTRACT FROM AUTHOR]

Aurivillius oxide semiconductors are important photocatalysts because of their unique electronic structure and layered crystal. In this paper, two kinds of Aurivillius oxide semiconductor heterostructures based on Bi4Ti3O12 nanofiber frameworks and Bi2XO6 (X = Mo, W) nanosheets are successfully synthesized by combining the electrospinning technique and solvothermal method. The high-resolution transmission electron microscopy results reveal that an intimate interface between Bi4Ti3O12 nanofibers and Bi2MoO6 or Bi2WO6 nanosheets forms in the heterojunctions. Photocatalytic tests show that the Bi4Ti3O12/Bi2XO6 (X = Mo, W) heterostructures exhibit enhanced photocatalytic activity than bare Bi4Ti3O12 and Bi2XO6 (X = Mo, W) under visible light, mainly owing to the photoinduced interfacial charge transfer based on the photosynergistic effect of the Bi4Ti3O12/Bi2XO6 heterojunction. The heterostructures can be reclaimed easily by sedimentation without a decrease of the photocatalytic activity due to the large length to diameter ratio of nanofiber frameworks. Moreover, such simple and versatile strategy can provide a general way to fabricate other heterostructures of Bi(III)-containing oxides, such as Bi4Ti3O12/BiVO4 and Bi4Ti3O12/BiOCl. [ABSTRACT FROM AUTHOR]