EPR and photoluminescence spectroscopy studies on the defect structure of ZnO nanocrystals
EPR and photoluminescence spectroscopy studies on the defect structure of ZnO nanocrystals
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DOI：
10.1103/physrevb.86.014113
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发表时间：
2012-07-26
影响因子：
3.7
通讯作者：
Erdem, Emre
中科院分区：
文献类型：
--
作者：
Kaftelen, Hulya;Ocakoglu, Kasim;Erdem, Emre
通过一种在低温下进行的新型铣削，可以微调ZnO纳米颗粒的结构和光学性质。本研究利用电子顺磁共振（EPR）和光致发光（PL）光谱对氧和锌空位等本征缺陷中心进行了表征。用EPR识别了三种不同的表面缺陷，它们具有不同的g因子，其光谱强度随晶体尺寸的减小而变化。EPR和PL强度呈线性相关关系，提供了ZnO的光学和电子性质的详细信息。基于光学发射和EPR建立的核壳模型表明，带隙中不同的电子态分别属于带负电的Zn空位和带正电的氧空位。该模型表明了红发射与带正电的氧空位之间的相关性，这可能导致从典型的n型到p型ZnO半导体的转变。
Structural and optical properties of ZnO nanoparticles can be fine tuned by a novel variant of milling performed at cryogenic temperatures. In this study intrinsic defect centers such as oxygen and zinc vacancies are characterized using electron paramagnetic resonance (EPR) and photoluminescence (PL) spectroscopy. Three different surface defects with different g factors were identified by EPR for which the spectral intensities change upon decreasing the crystal size. EPR and PL intensities revealed a linear correlation giving detailed information about optical and electronic properties of ZnO. The core-shell model established from optical emission and EPR suggests distinguished electronic states in the band gap belonging to negatively charged Zn vacancies and positively charged oxygen vacancies. This model indicates a correlation between red emission and positively charged oxygen vacancies, which lead to a possible transition from a typical n-type to a p-type ZnO semiconductor.