Plasma-induced enhancement of UV photoluminescence in ZnO nanowires
Plasma-induced enhancement of UV photoluminescence in ZnO nanowires
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DOI：
10.1039/c3ce41055b
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发表时间：
2013-01-01
期刊：
影响因子：
3.1
通讯作者：
Sberveglieri, Giorgio
中科院分区：
文献类型：
--
作者：
Baratto, Camilla;Comini, Elisabetta;Sberveglieri, Giorgio
采用等离子体刻蚀的方法对氧化锌纳米线的光致发光进行了修饰，使其在紫外区(3.26 eV)的近带边发射(NBE)显著增加。相反，600℃的退火处理使NBE峰消失。这为通过表面处理来改变氧化锌纳米线的发射性能提供了可能，对于氧化锌作为发射材料的应用具有重要意义。在管式加热炉中采用气相生长技术制备了氧化锌纳米线。用扫描电子显微镜和透射电子显微镜对薄膜的形貌和结构进行了表征，结果表明等离子体刻蚀后薄膜的形貌和晶型没有改变。纳米线为单晶，长径比大，直径在50-100 nm范围内。用连续波光致发光(PL)法研究了氧化锌纳米线的光学性质。经Ar和O2等离子体刻蚀处理后，样品的荧光光谱发生改变，NBE峰明显增强，NBE与深能级发射(DLE)的比值增大，表明处理后样品质量较好。由于O-2等离子体刻蚀得到的NbE：Del比Ar小，所以Ar处理的效果高于O-2处理的效果。相反，在O-2或Ar气氛中，在600℃的温度下热处理导致了NBE的猝灭和发光光谱中DLE的增加。从氢的扩散和引起非辐射复合的态钝化的角度讨论了光谱特征的变化。
The photoluminescence emission of ZnO nanowires was modified by means of plasma etching, inducing a strong increase in the Near Band Edge emission (NBE) in the UV region (3.26 eV). In contrast, annealing treatment at 600 degrees C quenched the NBE peak. This opens the possibility to modify the emission properties of ZnO nanowires by means of surface treatment, and is of great importance in view of the application of ZnO as an emitting material. ZnO nanowires were prepared by the vapour phase growth technique in a tubular furnace. Morphological and structural characterization was carried out by scanning and transmission electron microscopy, showing no modifications to the morphology and crystalline arrangements after plasma etching. The nanowires are single crystalline with a high aspect ratio and diameters in the 50-100 nm range. The optical properties of the ZnO nanowires were studied by continuous wave photoluminescence (PL). Ar and O-2 plasma etching treatment caused modification of the PL spectrum, inducing a strong enhancement of the NBE peak, and an increased ratio of NBE over Deep Level Emission (DLE), thus indicating a better sample quality after the treatment. The effect of the Ar treatment is higher than the effect of O-2 treatment, since the ratio of NBE : DLE obtained for O-2 plasma etching is smaller than the ratio observed for Ar. Conversely, annealing at 600 degrees C in an O-2 or Ar atmosphere induced the quenching of the NBE and an increase of the DLE in the PL spectrum of the ZnO nanowires. The variations in the spectroscopic features are discussed in terms of hydrogen diffusion and the passivation of states responsible for non-radiative recombination.