Institute of Materials Physics and Center for Nanotechnology, University of Muenster, Wilhelm-Klemm-Str. 10, 48149, Muenster, Germany.
Nanoscale. 2011 Nov;3(11):4830-9. doi: 10.1039/c1nr10806a. Epub 2011 Oct 10.
In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NWs) which play a critical role in the properties of the NWs, was studied with a combined innovative experimental analysis. The NWs prepared by both the aqueous solution method and chemical vapour deposition process were of increasing length and decreasing size-to-volume (S/V) ratio. The combined approach involved different analytical and spectroscopic techniques and from the correlation between the different measurements, the concentration of the oxygen vacancies jointly with the zinc interstitials defects and the zinc vacancy defects was observed to be positively or negatively correlated, respectively, with the magnitude of the photoluminescence intensity and radiative lifetimes. Furthermore, the experimental results also suggest that the oxygen vacancy defects are not only spatially located on the surface of the NW but an increasing fraction of the total oxygen vacancy defects connected with the green emission is also located in an annulus region beneath the surface as the ZnO NWs elongate. On the other hand, as the donor concentration plays a critical function in the properties of the ZnO NWs, an analytical model was derived for the calculation of the donor concentration of the NWs directly from its reverse-biased current-voltage characteristics obtained from the conductive atomic force microscopy measurements.
在本文中，通过结合创新的实验分析，研究了尺寸控制氧化锌纳米线（NWs）中本征缺陷的重要作用，这些缺陷在 NWs 的性质中起着关键作用。通过水相溶液法和化学气相沉积法制备的 NWs 的长度逐渐增加，而尺寸-体积（S/V）比逐渐减小。该综合方法涉及不同的分析和光谱技术，并且从不同测量之间的相关性来看，氧空位的浓度与锌间隙缺陷和锌空位缺陷的浓度分别呈正相关或负相关，分别与光致发光强度和辐射寿命的大小相关。此外，实验结果还表明，氧空位缺陷不仅位于 NW 的表面上，而且随着 ZnO NW 的伸长，与绿光发射相关的总氧空位缺陷的一部分也位于表面以下的环状区域中。另一方面，由于施主浓度在 ZnO NWs 的性质中起着关键作用，因此可以从通过导电原子力显微镜测量获得的反向偏置电流-电压特性直接推导出 NWs 的施主浓度的分析模型。
