鉛島於矽(100)-2X1表面受量子尺寸效應影響之低溫成長

Abstract

利用掃描穿隧顯微鏡研究低溫成長於矽Si(100)-2×1表面的鉛薄膜。有三種鉛島會形成: 六角形表面平坦的鉛(111)島嶼，長條型表面平坦的鉛(100)島嶼和長條型三維的鉛島嶼。對於表面平坦的鉛(111)島嶼，島的厚度局限在4~10個原子層之間。觀察其數量分布，以6層高的島嶼最多。這種成長行為起源於量子尺寸效應。利用掃描穿遂能譜不同厚度的島嶼測量到量子井態。利用量子力學中無限位能井模型可以解釋這個結果。此外，表面平坦的鉛(100)島嶼和三維的鉛島嶼每跨過一個臺階方向會轉90°。這現象意味著鉛(100)島嶼和三維的鉛島嶼會受到矽Si(100)-2×1表面重購的影響

The growth of Pb film on the Si(100)-2×1 surface has been investigated at low temperature using scanning tunneling microscopy. Three kinds of Pb islands are formed: hexagonal flat-top Pb(111) islands, rectangular flat-top Pb(100) islands, and rectangular 3D Pb islands. For flat-top Pb(111) islands, the thickness of islands is confined within the range of 4 to 10 atomic layers. Among these islands, those with heights of six layers are most abundant. This growth behavior is a result of the quantum size effect. Quantum well states are detected by scanning tunneling spectroscopy on the Pb islands of varying thickness. A simple model based on the infinite potential well can explain our results. Besides, flat-top Pb(100) islands and 3D islands rotate by 90° from one terrace to the next. This phenomenon implies that the structures of Pb(100) and 3D islands are influenced by the Si(100)-2×1 surface.