Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206West Green Street, Urbana, IL 61801, USA.
Nanotechnology. 2013 Jun 7;24(22):225305. doi: 10.1088/0957-4484/24/22/225305. Epub 2013 May 3.
This paper presents a non-lithographic approach to generate wafer-scale single crystal silicon nanowires (SiNWs) with controlled sidewall profile and surface morphology. The approach begins with silver (Ag) thin-film thermal dewetting, gold (Au) deposition and lift-off to generate a large-scale Au mesh on Si substrates. This is followed by metal-assisted chemical etching (MacEtch), where the Au mesh serves as a catalyst to produce arrays of smooth Si nanowires with tunable taper up to 13°. The mean diameter of the thus fabricated SiNWs can be controlled to range from 62 to 300 nm with standard deviations as small as 13.6 nm, and the areal coverage of the wire arrays can be up to 46%. Control of the mean wire diameter is achieved by controlling the pore diameter of the metallic mesh which is, in turn, controlled by adjusting the initial thin-film thickness and deposition rate. To control the wire surface morphology, a post-fabrication roughening step is added to the approach. This step uses Au nanoparticles and slow-rate MacEtch to produce rms surface roughness up to 3.6 nm.
本文提出了一种非光刻方法，可在硅片上生成具有可控侧壁轮廓和表面形貌的单晶硅纳米线（SiNWs）。该方法首先通过银（Ag）薄膜热去湿、金（Au）沉积和剥离，在 Si 衬底上生成大规模的 Au 网格。然后进行金属辅助化学蚀刻（MacEtch），其中 Au 网格作为催化剂，生成具有可调锥形的光滑 Si 纳米线阵列，锥形角度高达 13°。所制备的 SiNWs 的平均直径可以控制在 62 至 300nm 之间，标准偏差小至 13.6nm，并且线阵列的面积覆盖率高达 46%。通过控制金属网格的孔径来控制平均线直径，而金属网格的孔径又可以通过调整初始薄膜厚度和沉积速率来控制。为了控制线的表面形貌，在该方法中增加了后制造的粗糙化步骤。此步骤使用 Au 纳米粒子和慢速率 MacEtch 可产生高达 3.6nm 的均方根表面粗糙度。
