Ultralow therma conductivity of isotope-doped silicon nanowires

作者：Yang Nuo; Zhang Gang^*; Li Baowen

来源：Nano Letters, 2008, 8(1): 276-280.

DOI：10.1021/nl0725998

The thermal conductivity of silicon nanowires (SiNWs) is investigated by molecular dynamics (MD) simulation. It is found that the thermal conductivity of SiNWs can be reduced exponentially by isotopic defects at room temperature. The thermal conductivity reaches the minimum, which is about 27% of that of pure (28)Si NW, when doped with 50% isotope atoms. The thermal conductivity of isotopic-superlattice structured SiNWs depends clearly on the period of superlattice. At a critical period of 1.09 nm, the thermal conductivity is only 25% of the value of pure Si NW. An anomalous enhancement of thermal conductivity is observed when the superlattice period is smaller than this critical length. The ultralow thermal conductivity of superlattice structured SiNWs is explained with phonon spectrum theory.

• 出版日期2008-1