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Báo cáo hóa học: "Great blue-shift of luminescence of ZnO nanoparticle array constructed from ZnO quantum dots"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Great blue-shift of luminescence of ZnO nanoparticle array constructed from ZnO quantum dots | Wang et al. Nanoscale Research Letters 2011 6 338 http www.nanoscalereslett.eom content 6 1 338 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Great blue-shift of luminescence of ZnO nanoparticle array constructed from ZnO quantum dots Nengwen Wang Yuhua Yang and Guowei Yang Abstract ZnO nanoparticle array has been fabricated on the Si substrate by a simple thermal chemical vapor transport and condensation without any metal catalysts. This ZnO nanoparticles array is constructed from ZnO quantum dots QDs and half-embedded in the amorphous silicon oxide layer on the surface of the Si substrate. The cathodoluminescence measurements showed that there is a pronounced blue-shift of luminescence comparable to those of the bulk counterpart which is suggested to originate from ZnO QDs with small size where the quantum confinement effect can work well. The fabrication mechanism of the ZnO nanoparticle array constructed from ZnO QDs was proposed in which the immiscible-like interaction between ZnO nuclei and Si surface play a key role in the ZnO QDs cluster formation. These investigations showed the fabricated nanostructure has potential applications in ultraviolet emitters. Introduction Recently ZnO has attracted very great attention because of its particular properties in broad fields. For example it has a large direct band gap of 3.37 eV and excitonbinding energy of 60 meV while the Bohr radius of exciton is as small as approx. 2.34 nm. Thus ZnO is a promising candidate for the high efficient ultraviolet UV laser device 1-3 . Interestingly when the size of ZnO nanoparticles is smaller than the Bohr radius i.e. ZnO quantum dots QDS the quantum confinement has a notable influence on the band gap and further causes a series of novel characteristics such as the blueshift of luminescence 4-7 . Therefore there have been a variety of techniques to fabricate ZnO QDs 6-10 . Usually the size of ZnO QDs is slightly larger than or just comparable with the