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Surface Diffusion Coefficients of Adatoms on Strained Overlayers

스트레인을 받고 있는 표면에서의 원자 확산계수

  • Chung, K.H. (Department of Physics, Korea University) ;
  • Yoon, J.K. (Department of Physics, Korea University) ;
  • Kim, H. (Department of Physics, Korea University) ;
  • Kahng, S.J. (Department of Physics, Korea University)
  • Published : 2008.09.30

Abstract

Adatom kinetics on the surfaces of Co overlayers, prepared on the W(110) surface, was studied with scanning tunneling microscopy. By counting the number-density of the adatom-islands, we estimated the ratio of adatom diffusion coefficients. The ratio $D_{W(110)}:D_{1ML\;Co}:D_{2ML\;Co}$ was measured to be 1 : 125 : 33000 at room temperature, where $D_{W(110)},\;D_{1ML\;Co}$, and $D_{2ML\;Co}$ are the diffusion coefficients on bare W(110) surface, on one-monolayer Co overlayer, and on two-monolayers Co overlayers, respectively. An increased diffusion coefficient on two-ML Co overlayers, relative to that on one-ML Co overlayers, was explained with the heteroepitaxial strain effect.

W(110) 표면에 성장한 Co 박막에서 원자 정역학을 주사터널링 현미경으로 연구했다. 원자섬의 개수 밀도를 측정하여 원자 확산 계수의 비를 알 수 있었다. W(110) 표면, Co가 1 원자층 성장된 표면, Co가 2 원자층 성장된 표면의 원자 확산 계수의 비는 상온에서 1:124:33000인 것으로 측정되었다. Co가 2 원자층 성장된 표면의 확산 계수가 Co 가 1 원자층 성장된 표면의 확산 계수보다 큰 것은 이종성장의 스트레인 효과로 인한 것으로 해석되었다.

Keywords

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