LEEM STUDIES OF PHASE SEPARATIONS AND SURFACE DEPLETION OF Co AND Ni ON Si(111)
LEEM STUDIES OF PHASE SEPARATIONS AND SURFACE DEPLETION OF Co AND Ni ON Si(111)
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Si(111)上Co和Ni的相分离和表面损耗的LEEM研究
DOI：
10.1142/s0218625x98001511
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
P. Bennett
中科院分区：
文献类型：
--
作者：
R. Phaneuf;P. Bennett
Si（111）表面在700°C附近亚单层沉积Co或Ni时的低能电子显微镜图像显示相分离为无序的“环簇”相和有序的7 × 7重构。对于Co/Si（111），我们发现在固定剂量下温度驱动的相分离是可逆的，并且发生在固定的表面覆盖率下。相边界的形状揭示了无序相中含钴环团簇之间的排斥相互作用。对于Ni/Si（111），溶解到本体中防止表面相之间的可逆分离。当覆盖度接近1/7 ML时，Co/Si（111）形成了有序的密排环团簇相，而Ni/Si（111）则没有。由于稳定硅化物岛的成核和生长，该相在加热时不可逆地消失。
Low energy electron microscopy images of Si(111) surfaces during sub monolayer deposition of Co or Ni at temperatures near 700°C reveal a phase separation into a disordered "ring cluster" phase and the ordered 7 × 7 reconstruction. For Co/Si(111) we find that temperature-driven phase separations at a fixed dose are reversible and occur at a fixed surface coverage. The shape of the phase boundary reveals a repulsive interaction between Co-containing ring clusters in the disordered phase. For Ni/Si(111), dissolution into the bulk prevents reversible separations between surface phases. At coverages close to 1/7 ML an ordered close-packed ring cluster phase forms for Co/Si(111), but not for Ni/Si(111). The phase disappears irreversibly on heating, due to the nucleation and growth of stable silicide islands.