Controlled synthesis of millimeter-long silicon nanowires with uniform electronic properties.

We report the nanocluster-catalyzed growth of ultra-long and highly-uniform single-crystalline silicon nanowires (SiNWs) with millimeter-scale lengths and aspect ratios up to ca. 100,000. The average SiNW growth rate using disilane (Si2H6) at 400 °C was 31 µm/min, while the growth rate determined for silane (SiH4) reactant under similar growth conditions was 130 times lower. Transmission electron microscopy studies of millimeter-long SiNWs with diameters of 20–80 nm show that the nanowires grow preferentially along the <110> direction independent of diameter. In addition, ultra-long SiNWs were used as building blocks to fabricate one-dimensional arrays of field-effect transistors (FETs) consisting of ca. 100 independent devices per nanowire. Significantly, electrical transport measurements demonstrated that the millimeter-long SiNWs had uniform electrical properties along the entire length of wires, and each device can behave as a reliable FET with an on-state current, threshold voltage, and transconductance values (average ± 1 standard deviation) of 1.8 ± 0.3 µA, 6.0 ± 1.1 V, 210 ± 60 nS, respectively. Electronically-uniform millimeter-long SiNWs were also functionalized with monoclonal antibody receptors, and used to demonstrate multiplexed detection of cancer marker proteins with a single nanowire. The synthesis of structurally- and electronically-uniform ultra-long SiNWs may open up new opportunities for integrated nanoelectronics, and could serve as unique building blocks linking integrated structures from the nanometer through millimeter length scales.

我们报道了纳米团簇催化生长的超长且高度均匀的单晶硅纳米线（SiNWs），其长度可达毫米级，长径比高达约100,000。在400°C下使用乙硅烷（Si₂H₆）时，硅纳米线的平均生长速率为31 µm/min，而在类似生长条件下，以硅烷（SiH₄）为反应物时所确定的生长速率要低130倍。对直径为20 - 80 nm的毫米长硅纳米线进行的透射电子显微镜研究表明，纳米线优先沿<110>方向生长，与直径无关。此外，超长硅纳米线被用作构建模块来制造场效应晶体管（FET）的一维阵列，每条纳米线包含约100个独立器件。值得注意的是，电学传输测量表明，毫米长的硅纳米线在整个线长上具有均匀的电学性能，并且每个器件都可作为可靠的场效应晶体管，其导通电流、阈值电压和跨导值（平均值±1标准偏差）分别为1.8 ± 0.3 µA、6.0 ± 1.1 V、210 ± 60 nS。电学均匀的毫米长硅纳米线还被单克隆抗体受体功能化，并用于展示用单根纳米线对癌症标志物蛋白进行多重检测。结构和电学均匀的超长硅纳米线的合成可能为集成纳米电子学开辟新的机遇，并可作为独特的构建模块，将从纳米到毫米长度尺度的集成结构连接起来。