Electroluminescence behavior of ZnO/Si heterojunctions: Energy band alignment and interfacial microstructure
Electroluminescence behavior of ZnO/Si heterojunctions: Energy band alignment and interfacial microstructure
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ZnO/Si 异质结的电致发光行为：能带排列和界面微观结构
DOI：
10.1063/1.3385384
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发表时间：
2010-04-15
影响因子：
3.2
通讯作者：
Chu, Paul K.
中科院分区：
文献类型：
--
作者：
You, J. B.;Zhang, X. W.;Chu, Paul K.
n-ZnO/p-Si异质结发光二极管（LED）显示出弱的缺陷相关电致发光（EL）。为了分析弱电致发光的成因，利用X射线光电子能谱（XPS）研究了ZnO/Si异质结的能带排列和界面微结构。价带偏移（VBO）被确定为3.15 +/-0.15eV，并且导带偏移为-0.90 +/-0.15eV，示出了II型带排列。较高的VBO意味着从Si注入ZnO的空穴的高势垒，因此，电荷载流子复合主要发生在Si侧而不是ZnO层上。在ZnO/Si界面处形成了2.1nm厚的SiOx界面层。不可避免的SiOx界面层在ZnO/Si界面处提供了大量的非辐射中心，并且在ZnO膜中引起差的结晶度。n-ZnO/p-Si LED的弱EL可归因于高ZnO/Si VBO和SiOx界面层的存在。(C)2010年美国物理学会。[doi：10.1063/1.3385384]
n-ZnO/p-Si heterojunction light-emitting diodes (LEDs) show weak defect-related electroluminescence (EL). In order to analyze the origin of the weak EL, the energy band alignment and interfacial microstructure of ZnO/Si heterojunction are investigated by x-ray photoelectron spectroscopy. The valence band offset (VBO) is determined to be 3.15 +/- 0.15 eV and conduction band offset is -0.90 +/- 0.15 eV, showing a type-II band alignment. The higher VBO means a high potential barrier for holes injected from Si into ZnO, and hence, charge carrier recombination takes place mainly on the Si side rather than the ZnO layer. It is also found that a 2.1 nm thick SiOx interfacial layer is formed at the ZnO/Si interface. The unavoidable SiOx interfacial layer provides to a large number of nonradiative centers at the ZnO/Si interface and gives rise to poor crystallinity in the ZnO films. The weak EL from the n-ZnO/p-Si LEDs can be ascribed to the high ZnO/Si VBO and existence of the SiOx interfacial layer. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3385384]