Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) & Hysitron Applied Research Center in China (HARCC), State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University , Xi'an 710049, P. R. China.
Hysitron Incorporated, 9625 West 76th St, Minneapolis, Minnesota 55344, United States.
Nano Lett. 2015 Dec 9;15(12):7886-92. doi: 10.1021/acs.nanolett.5b02852. Epub 2015 Nov 5.
Great efforts have been made to synthesize ZnO nanowires (NWs) as building blocks for a broad range of applications because of their unique mechanical and mechanoelectrical properties. However, little attention has been paid to the correlation between the NWs synthesis condition and these properties. Here we demonstrate that by slightly adjusting the NW growth conditions, the cross-sectional shape of the NWs can be tuned from hexagonal to circular. Room temperature photoluminescence spectra suggested that NWs with cylindrical geometry have a higher density of point defects. In situ transmission electron microscopy (TEM) uniaxial tensile-electrical coupling tests revealed that for similar diameter, the Young's modulus and electrical resistivity of hexagonal NWs is always larger than that of cylindrical NWs, whereas the piezoresistive coefficient of cylindrical NWs is generally higher. With decreasing diameter, the Young's modulus and the resistivity of NWs increase, whereas their piezoresistive coefficient decreases, regardless of the sample geometry. Our findings shed new light on understanding and advancing the performance of ZnO-NW-based devices through optimizing the synthesis conditions of the NWs.
研究人员已经做出了巨大努力来合成氧化锌纳米线（NWs），因为它们具有独特的机械和机电性能，所以将其作为各种应用的构建块。然而，人们很少关注 NWs 合成条件与这些性能之间的关系。在这里，我们证明通过稍微调整 NW 的生长条件，可以将 NW 的横截面形状从六边形调至圆形。室温光致发光光谱表明，具有圆柱几何形状的 NW 具有更高密度的点缺陷。原位透射电子显微镜（TEM）单向拉伸-电耦合测试表明，对于相似的直径，六边形 NW 的杨氏模量和电阻率始终大于圆柱形 NW，而圆柱形 NW 的压阻系数通常更高。随着直径的减小，NW 的杨氏模量和电阻率增加，而压阻系数减小，与样品几何形状无关。我们的研究结果为通过优化 NW 的合成条件来理解和提高基于 ZnO-NW 的器件的性能提供了新的思路。
