A SnO2 Nanoparticle/Nanobelt and Si Heterojunction Light-Emitting Diode

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• 作者：Bo Ling ; Xiao Wei Sun ; Jun Liang Zhao ; Chang Ke ; Swee Tiam Tan ; Rui Chen ; Han Dong Sun ; Zhi Li Dong
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：November 4, 2010
• 年：2010
• 卷：114
• 期：43
• 页码：18390-18395
• 全文大小：340K
• 年卷期：v.114,no.43(November 4, 2010)
• ISSN：1932-7455

文摘

Single-crystalline zero-dimensional tin dioxide (SnO₂) nanoparticles and one-dimensional SnO₂ nanobelts were synthesized on silicon (Si) substrates with different seed layer coatings by simple vapor-phase transport method. The crystal structure and morphology of the as-synthesized products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman scattering spectroscopy. Both geometrically different nanostructures were further employed to fabricate the light-emitting diodes and showed dominant red and green emission bands at room temperature, which were ascribed to the deep defect states in SnO₂. However, SnO₂-nanobelts-based light-emitting diodes showed another violet emission peaking at ca. 400 nm which was attributed to the shallow defect state related to the surface states/defects. The different emission performance between nanoparticle and nanobelts devices was attributed to the larger surface-to-volume ratio of the nanobelts, which was confirmed by the Raman and photoluminescence analysis. A thin SiO₂ intermediate layer was found to be crucial in achieving light emission from a n-SnO₂/p-Si heterojunction with large valence band offset (ca. 2.96 eV), by which sufficient potential-energy difference can be maintained between SnO₂ and Si, thus facilitating the tunneling injection of holes.