Zn2SiO4/ZnO Core/Shell Coaxial Heterostructure Nanobelts Formed by an Epitaxial Growth

被引:10
作者
Cheng, Baochang [1 ,2 ]
Yu, Xiaoming [1 ,2 ]
Liu, Hongjuan [1 ,2 ]
Wang, Zhanguo [3 ]
机构
[1] Nanchang Univ, Inst Adv Studying, Nanchang 330031, Peoples R China
[2] Nanchang Univ, Sch Mat Sci & Engn, Nanchang 330031, Peoples R China
[3] Chinese Acad Sci, Inst Semicond, Key Lab Semicond Mat Sci, Beijing 100083, Peoples R China
关键词
D O I
10.1021/jp8045824
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Si-doped ZnO can be synthesized on the surface of the early grown Zn2SiO4 nanostructures and form core/ shell coaxial heterostructure nanobelts with an epitaxial orientation relationship. A parallel interface with a periodicity array of edge dislocations and an inclined interface without dislocations can be formed. The visible green emission is predominant in PL spectra due to carrier localization by high density of deep traps from complexes of impurities and defects. Due to band tail localization induced by composition and defect fluctuation, and high density of free-carriers donated by doping, especially the further dissociation of excitons into free-carriers at high excitation intensity, the near-band-edge emission is dominated by the transition of free-electrons to free-holes, and furthermore, exhibits a significant excitation power-dependent red-shift characteristic. Due to the structure relaxation and the thermalization effects, carrier delocalization takes place in deep traps with increasing excitation density. As a result, the green emission passes through a maximum at 0.25I(0) excitation intensity, and the ratio of the violet to green emission increases monotonously as the excitation laser power density increases. The violet and green emission of ZnO nanostructures can be well tuned by a moderate doping and a variation in the excitation density.
引用
收藏
页码:16312 / 16317
页数:6
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