Silicon nanowire band gap modification
Silicon nanowire band gap modification
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DOI：
10.1021/nl061888d
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发表时间：
2007-01-01
期刊：
影响因子：
10.8
通讯作者：
Frauenheim, Thomas
中科院分区：
文献类型：
--
作者：
Nolan, Michael;O'Callaghan, Sean;Frauenheim, Thomas
采用密度泛函理论计算方法，研究了小直径(约1 nm)硅纳米线在不同表面端接方式下的带隙修正。由于量子限制，小直径的导线表现出直接的带隙，该带隙随着导线直径的缩小而增加，与表面端接无关。这一效应已经在以前对氢化丝的实验和理论研究中观察到。对于固定的截面，用于饱和硅表面的官能团显著改变了带隙，导致高达1电子伏的相对能量移动。带隙的移动可以追溯到硅价带和终止基团的前线轨道之间杂化的细节，这与量子限制竞争。
Band gap modification for small-diameter (similar to 1 nm) silicon nanowires resulting from the use of different species for surface termination is investigated by density functional theory calculations. Because of quantum confinement, small-diameter wires exhibit a direct band gap that increases as the wire diameter narrows, irrespective of surface termination. This effect has been observed in previous experimental and theoretical studies for hydrogenated wires. For a fixed cross-section, the functional group used to saturate the silicon surface significantly modifies the band gap, resulting in relative energy shifts of up to an electronvolt. The band gap shifts are traced to details of the hybridization between the silicon valence band and the frontier orbitals of the terminating group, which is in competition with quantum confinement.