Pan Hui, Chen Weizhe, Lim San Hua, Poh Chee Koh, Wu Xiaobing, Feng Yuanping, Ji Wei, Lin Jianyi
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
J Nanosci Nanotechnol. 2005 May;5(5):733-7. doi: 10.1166/jnn.2005.095.
Si nanowires (SiNWs) have been produced by thermal vaporization on Si(111) substrate without catalysts added. The grown SiNWs have been characterized by Raman scattering, SEM, XRD, and electron diffraction and shown to be highly crystalline with only little impurities such as amorphous Si and silicon oxides. Photoluminescence (PL) study has illustrated that the Si band-to-band gap increases from 1.1 eV for bulk Si to 1.56 eV for the as-grown SiNWs due to quantum confinement effect. A strong PL peak at 521 nm (2.37 eV) is attributed to the relaxation of the photon-induced self-trapped state in the form of surface Si-Si dimers, which may also play an important role in optical limiting of SiNWs with 532-nm nanosecond laser pulses. With the observation of optical limiting at 1064 nm, nonlinear scattering is believed to make a dominant contribution to the nonlinear response of SiNWs.
通过在不添加催化剂的情况下在Si(111)衬底上进行热蒸发制备了硅纳米线（SiNWs）。所生长的SiNWs已通过拉曼散射、扫描电子显微镜（SEM）、X射线衍射（XRD）和电子衍射进行了表征，结果表明其具有高度结晶性，仅含有少量诸如非晶硅和氧化硅之类的杂质。光致发光（PL）研究表明，由于量子限制效应，硅的带隙从块状硅的1.1 eV增加到所生长SiNWs的1.56 eV。在521 nm（2.37 eV）处的一个强PL峰归因于以表面Si-Si二聚体形式存在的光致自陷态的弛豫，这在532 nm纳秒激光脉冲作用下SiNWs的光学限幅中可能也起着重要作用。通过观察在1064 nm处的光学限幅，认为非线性散射对SiNWs的非线性响应起主要作用。
