鈷在銀/鍺(111)-c(2×8)及鈷在銀/鍺(111)-(√3×√3)及(4×4)表面的結構衍化

Abstract

我們利用歐傑電子能譜(Auger electron spectroscopy，AES)、低能量電子繞射(low-energy electron diffraction )來深入探討銀在鍺(111)-c(2×8)及鈷在銀/鍺(111)-(√3×√3)R30°及(4×4)隨著不同退火溫度下表面的結構衍化。 室溫下，銀原子在鍺(111)的成長模式為層狀成長之後再以三維島狀的Stranstri-Krastanov (SK) mode。室溫蒸鍍不同鍍量的銀在鍺(111)-c(2×8)上並退火到420 K至930 K之間，隨著溫度上升至570 K，超過1 ML的銀原子會退吸附直到剩下1 ML的銀，最後在退火溫度為930 K時，銀原子會完全退吸附。在退火過程中，隨著不同的退火溫度及銀鍍量，銀/鍺(111)的結構，由原本的c(2×8)分別會形成(1×1)、(3×1)、(4×4)或(√3×√3)R30°的結構。 室溫蒸鍍鈷在銀/鍺(111)-(√3×√3) R30°及(4×4)上並退火到420 K至930 K之間，鈷在銀/鍺(111)-(√3×√3)R30°及(4×4)的結構上，在退火溫度570 K時，鈷會形成(√13×√13)及(2×2)的重構，而在退火溫度為650 K和730 K時，鈷都是形成(2×2)的重構，在退火溫度為830 K時，鈷原子會退吸附，此結果顯示鈷與基底不會形成合金。

The growth of Ag atoms on Ge(111)-c(2×8) and Co atoms on Ag/Ge(111)-(√3×√3)R30° and (4×4) surfaces followed by annealing at temperature ranging from 420 K to 930 K has been studied by Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED). The formation of Ag films on the Ge(111) was found to support Stranstri-Krastanov growth mode. The sample was prepared by room-temperature Ag atoms deposition onto Ge(111), followed by annealing at the temperature ranging from 420 K to 930 K. The redundant Ag atoms desorbed until only 1ML Ag left on the surface at annealing temperature 570 K. After annealing at 930 K, all the Ag atoms desorbed from the surface. This procedure resulted in a number of structure transformations that are ranging from the native c(2×8) into (1×1), (3×1), (4×4), or (√3×√3)R30° structure. Co atoms were deposited on the Ag/Ge(111)-(√3×√3)R30° and (4×4) surface at room temperature and annealed at temperature ranging from 420 K to 930 K. After annealed to 570 K, Co atoms on the Ag/Ge(111)-(4×4) and (√3×√3)R30° surface formed (√13×√13) and (2×2) reconstruction. After annealing to 650 K and 730 K, Co formed (2×2 reconstruction. After annealing to 830 K, Co atoms completely diffused into the Ge(111) substrate.