利用固態反應法製備矽化鎳/矽化鉑奈米線軸向異質結構之研究

Abstract

過渡金屬矽化物奈米線同時具備矽奈米線的尺寸優勢與過渡金屬矽化物優良的物理特性，因此成為近年來最受矚目的奈米材料之一。然而目前的研究大多只局限於單一金屬矽化物奈米線系統，而多相金屬矽化物奈米線異質結構的相關研究卻十分稀少。故本研究利用固態反應法能同時形成多種矽化物與容易控制生長距離的優點，成功在650 ℃下製備出矽化鎳/矽/矽化鉑三相、矽化鎳/矽化鉑雙相以及鉑鎳矽三元相等多種奈米線軸向異質結構，同時透過臨場穿透式電子顯微鏡觀察矽化鎳與矽化鉑的成長過程與擴散行為。接著藉由球面像差修正掃描穿透式電子顯微鏡進行結構與成分的鑑定，分析結果顯示本實驗製備出來的產物為θ-Ni2Si與β-Pt2Si奈米線異質結構。此外，本研究還針對各種奈米線異質結構進行物理特性的量測，包含了電性與光學感測等，其中發現Ni2Si與Pt2Si所形成的三元相奈米線異質結構具有Ni2Si或Pt2Si奈米線所沒有的紅外光感測特性。以上的研究成果預期對未來的奈米材料或多相異質結構材料的相關研究與應用帶來重要的參考價值。

Transition metal silicide nanowires (NWs) have attracted increasing attention as they possess both advantages of silicon nanowires and transition metals. Over the past years, there are only reports with efforts on one silicide in single silicon nanowire. However, the research about two or more silicides in single silicon is still rare. In this thesis, we successfully fabricated θ-Ni2Si/Si/β-Pt2Si, θ-Ni2Si/β-Pt2Si and Ni,Pt,Si ternary phase axial nanowire heterostructures through solid-state reactions at 650 ℃. The growth mechanism and diffusion behavior of silicide nanowire heterostructures were studied by in-situ transmission electron microscope. Spherical aberration corrected scanning transmission electron microscope was used to analyze the phase structure and composition of silicide nanowire heterostructures. Moreover, electrical and photon sensing properties for the silicide nanowire heterostructures were investigated. We found that Ni,Pt,Si ternary phase nanowire heterostructures have excellent infrared light sensing property which is absent in bulk Ni2Si or Pt2Si. The above results would benefit the further understanding in heterostructured nano materials.