Beijing National Center for Electron Microscopy, Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084, PR China.
ACS Nano. 2011 Aug 23;5(8):6629-36. doi: 10.1021/nn202075z. Epub 2011 Jul 22.
We have developed a method combining lithography and catalytic etching to fabricate large-area (uniform coverage over an entire 5-in. wafer) arrays of vertically aligned single-crystal Si nanowires with high throughput. Coaxial n-Si/p-SiGe wire arrays are also fabricated by further coating single-crystal epitaxial SiGe layers on the Si wires using ultrahigh vacuum chemical vapor deposition (UHVCVD). This method allows precise control over the diameter, length, density, spacing, orientation, shape, pattern and location of the Si and Si/SiGe nanowire arrays, making it possible to fabricate an array of devices based on rationally designed nanowire arrays. A proposed fabrication mechanism of the etching process is presented. Inspired by the excellent antireflection properties of the Si/SiGe wire arrays, we built solar cells based on the arrays of these wires containing radial junctions, an example of which exhibits an open circuit voltage (V(oc)) of 650 mV, a short-circuit current density (J(sc)) of 8.38 mA/cm(2), a fill factor of 0.60, and an energy conversion efficiency (η) of 3.26%. Such a p-n radial structure will have a great potential application for cost-efficient photovoltaic (PV) solar energy conversion.
我们开发了一种结合光刻和催化刻蚀的方法，以高效率制备大面积（整个 5 英寸晶圆全覆盖）垂直排列的单晶硅纳米线阵列。通过在硅纳米线表面进一步使用超高真空化学气相沉积（UHVCVD）方法外延生长单晶 SiGe 层，还可以制备同轴的 n-Si/p-SiGe 纳米线阵列。这种方法可以精确控制硅和硅/硅锗纳米线阵列的直径、长度、密度、间距、取向、形状、图案和位置，从而有可能基于合理设计的纳米线阵列来制造器件阵列。提出了一种刻蚀过程的制造机制。受 Si/SiGe 纳米线阵列优异的抗反射性能的启发，我们构建了基于这些纳米线阵列的太阳能电池，其中包含径向结，一个示例的开路电压 (V(oc)) 为 650 mV，短路电流密度 (J(sc)) 为 8.38 mA/cm(2)，填充因子为 0.60，能量转换效率 (η) 为 3.26%。这种 p-n 径向结构将在高效、低成本的光伏 (PV) 太阳能转换方面具有巨大的应用潜力。
