鐵在鍺(111)-c(2×8)及銀/鍺(111)-(√3×√3) 表面上隨溫度衍化的行為

Abstract

在室溫下蒸鍍少量鐵原子於鍺(111)-c(2×8)上，並進行一連串加熱退火的實驗，以穿隧掃描顯微鏡對其形貌進行觀測。從STM的影像圖和對表面上原子島的體積分析，顯示隨著加熱退火溫度的提升，鐵會在鍺基底上造成缺陷與破洞，藉以拉出鍺進行合金使體積增加，並形成數種不同形貌的島嶼。最終當加熱退火溫度達到840K以上後，表面上的原子團會聚集成數種巨大的原子島。 再來將銀蒸鍍至鍺(111)-c(2×8)表面上，將其加熱退火使樣品表面重構為銀/鍺(111)-(√3×√3)後，蒸鍍少量鐵再度進行加熱退火的實驗。與鐵鍺系統的實驗結果比較後發現，銀能夠保護基底上不會出現缺陷，但仍無法阻止鐵在加熱退火溫度升高後從基底拉出鍺進行合金。於鐵銀鍺系統中發現的原子島種類和鐵鍺系統中大致相同，但鐵銀鍺系統中出現新種類的島和一些跡象顯示銀對於鐵鍺合金的成長仍有影響力。By scanning tunneling microscope, the Ge(111)-c(2×8) substrate which deposited less than one monolayer Iron atoms in room temperature, and its thermal evolution by annealing to different temperature was investigated. As the annealing temperature rises, iron will cause many defects and holes on the substrate to pull out germanium. Then they mix and form some kinds of alloy islands, this makes the total volume of islands above the surface increase. After annealing temperature above 840K, only few giant Fe-Ge alloys islands remain on the surface. In the different experiment, we deposit Fe on Ag/Ge(111)-(√3×√3) and observe the thermal evolution. The results show that silver as the buffer layer can protect the (√3×√3) reconstruction suffering from defects, but can't prevent Iron digging on substrate and alloying with germanium when annealing temperature rises. The kinds of island in FeGe and FeAgGe system are similar, but few difference show that silver still have some effect on the development of islands.