Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States.
ACS Nano. 2011 Oct 25;5(10):8383-90. doi: 10.1021/nn203166w. Epub 2011 Oct 10.
Silicon nanowires (NWs) have stimulated significant interest and found numerous applications; however, many applications will require a bulk quantity of nanowires to be synthesized in a reliable way. In this paper, we report the bulk synthesis of silicon nanowires on millimeter scale Al(2)O(3) spheres with a thermal chemical vapor deposition system (CVD) via the vapor-liquid-solid (VLS) growth mechanism. The spherical substrates enable the realization of Si nanowire synthesis on three-dimensional surfaces in comparison with the synthesis on a planar, two-dimensional wafer substrate. By modifying temperature in the recipe of synthesis, both single-crystalline and crystalline core/amorphous shell Si nanowires were obtained with this nanowire-on-spherical-support method. Conspicuous distinction in crystallinity of the nanowires was revealed by transmission electron microscopy characterization. The crystalline core/amorphous shell Si nanowires were utilized to form the anode of Li-ion battery half-cells with the traditional slurry method. Galvanostatic measurement demonstrated that the maximum power capacity achievable by the electrodes was 3500 mAh/g and capacity sustained at 1100 mAh/g after 60 cycles of charging and discharging.
硅纳米线（NWs）引起了极大的兴趣，并找到了许多应用；然而，许多应用将需要大量的纳米线以可靠的方式合成。在本文中，我们通过热化学气相沉积系统（CVD）在毫米级 Al2O3 球体上报告了硅纳米线的批量合成，采用的是汽-液-固（VLS）生长机制。与在平面二维晶片衬底上的合成相比，球形衬底能够实现三维表面上的 Si 纳米线合成。通过在合成配方中改变温度，使用这种纳米线在球形衬底上的方法获得了单晶和多晶核/非晶壳 Si 纳米线。通过透射电子显微镜表征揭示了纳米线结晶度的明显区别。使用晶态核/非晶壳硅纳米线通过传统的浆料法形成锂离子电池半电池的阳极。恒流测量表明，电极可实现的最大功率容量为 3500 mAh/g，在充电和放电 60 次后可持续保持 1100 mAh/g 的容量。
