Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Improved characteristics of near-band-edge and deep-level emissions from ZnO nanorod arrays by atomic-layer-deposited Al2O3 and ZnO shell layers | Sun et al. Nanoscale Research Letters 2011 6 556 http content 6 1 556 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Improved characteristics of near-band-edge and deep-level emissions from ZnO nanorod arrays by atomic-layer-deposited Al2O3 and ZnO shell layers Wen-Cheng Sun1 2 Yu-Cheng Yeh1 2 Chung-Ting Ko1 Jr-Hau He2 and Miin-Jang Chen1 Abstract We report on the characteristics of near-band-edge NBE emission and deep-level band from ZnO Al2O3 and ZnO ZnO core-shell nanorod arrays NRAs . Vertically aligned ZnO NRAs were synthesized by an aqueous chemical method and the Al2O3 and ZnO shell layers were prepared by the highly conformal atomic layer deposition technique. Photoluminescence measurements revealed that the deep-level band was suppressed and the NBE emission was significantly enhanced after the deposition of Al2O3 and ZnO shells which are attributed to the decrease in oxygen interstitials at the surface and the reduction in surface band bending of ZnO core respectively. The shift of deep-level emissions from the ZnO ZnO core-shell NRAs was observed for the first time. Owing to the presence of the ZnO shell layer the yellow band associated with the oxygen interstitials inside the ZnO core would be prevailed over by the green luminescence which originates from the recombination of the electrons in the conduction band with the holes trapped by the oxygen vacancies in the ZnO shell. PACS h . Introduction Because of large surface-to-volume ratio and spatial confinement of carriers researches on one-dimensional 1D nanostructures have attracted great interest 1-3 and remarkable progress has been achieved in various electronic photonic and sensing devices 3-7 . Novel synthetic approaches to the fabrication of high-quality semiconductor nanotubes have been reviewed by Yan et al. 8 . Zinc oxide ZnO has been regarded as one of the most promising .
