Small-diameter silicon nanowire surfaces
Small-diameter silicon nanowire surfaces
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DOI：
10.1126/science.1080313
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发表时间：
2003-03-21
期刊：
影响因子：
56.9
通讯作者：
Lee, ST
中科院分区：
文献类型：
--
作者：
Ma, DDD;Lee, CS;Lee, ST
小直径（11至7纳米）的硅纳米线（SiNWs）的制备，和它们的表面去除氧化物和终止与氢通过氢氟酸浸渍。这些硅纳米线的扫描隧道显微镜（STM），在空气和微真空中进行，揭示了原子分辨的图像，可以解释为氢封端的Si（1111）-（1 × 1）和Si（001）-（1 × 1）的表面对应的Si（1111）和Si（001）上的SiH 2分别。这些氢封端的硅纳米线表面似乎比常规硅晶片表面更抗氧化，因为在暴露于周围环境几天后在空气中获得了硅纳米线的原子分辨STM图像。对氧化物去除的SiNW进行扫描隧道光谱测量，并用于评估电子能隙。发现能隙随着SiNW直径的减小而增加，从7纳米的1.1电子伏到1.3纳米的3.5电子伏，与以前的理论预测一致。
Small-diameter (11 to 7 nanometers) silicon nanowires (SiNWs) were prepared, and their surfaces were removed of oxide and terminated with hydrogen by a hydrofluoric acid dip. Scanning tunneling microscopy (STM) of these SiNWs, performed both in air and in ultrahigh vacuum, revealed atomically resolved images that can be interpreted as hydrogen-terminated Si (1111)-(1 x 1) and Si (001)-(l x 1) surfaces corresponding to SiH3 on Si (1111) and SiH2 on Si (001), respectively. These hydrogen-terminated SiNW surfaces seem to be more oxidation-resistant than regular silicon wafer surfaces, because atomically resolved STM images of SiNWs were obtained in air after several days' exposure to the ambient environment. Scanning tunneling spectroscopy measurements were performed on the oxide-removed SiNWs and were used to evaluate the electronic energy gaps. The energy gaps were found to increase with decreasing SiNW diameter from 1.1 electron volts for 7 nanometers to 3.5 electron volts for 1.3 nanometers, in agreement with previous theoretical predictions.