Cantero Esteban D, Solis Lara M, Tong Yongfeng, Fuhr Javier D, Martiarena María Luz, Grizzi Oscar, Sánchez Esteban A
Centro Atómico Bariloche, Comisión Nacional de Energía Atómica CNEA, Consejo Nacional de Investigaciones Científicas y Técnicas CONICET, Instituto Balseiro, Universidad Nacional de Cuyo, Argentina.
Phys Chem Chem Phys. 2017 Jul 19;19(28):18580-18586. doi: 10.1039/c7cp02949g.
We studied the growth of Ge layers on Au(111) under ultra-high vacuum conditions from the submonolayer regime up to a few layers with Scanning Tunneling Microscopy (STM), Direct Recoiling Spectroscopy (DRS) and Low Energy Electron Diffraction (LEED). Most STM images for the thicker layers are consistent with a commensurate 5 × 8 arrangement. The high surface sensitivity of TOF-DRS allows us to confirm the coexistence of Au and Ge atoms in the top layer for all stages of growth. An estimation of the Au to Ge ratio at the surface of the thick layer gives about 1 Au atom per 2 Ge ones. When the growth is carried out at sample temperatures higher than about 420 K, a fraction of the deposited Ge atoms migrate into the bulk of Au. This incorporation of Ge into the bulk reduces the growth rate of the Ge films, making it more difficult to obtain films thicker than a few layers. After sputtering the Ge/Au surface, the segregation of bulk Ge atoms to the surface occurs for temperatures ≥600 K. The surface obtained after segregation of Ge reaches a stable condition (saturation) with an n × n symmetry with n on the order of 14.
我们在超高真空条件下，利用扫描隧道显微镜（STM）、直接反冲光谱（DRS）和低能电子衍射（LEED），研究了从亚单层到几层的Ge层在Au(111)上的生长情况。较厚Ge层的大多数STM图像与5×8的共格排列一致。飞行时间DRS的高表面灵敏度使我们能够确认在生长的各个阶段，顶层中Au和Ge原子共存。对厚层表面Au与Ge比例的估计表明，每2个Ge原子约有1个Au原子。当在高于约420 K的样品温度下进行生长时，一部分沉积的Ge原子会迁移到Au的体相中。Ge掺入体相降低了Ge膜的生长速率，使得获得几层以上的膜更加困难。在溅射Ge/Au表面后，对于温度≥600 K，体相Ge原子会偏析到表面。Ge偏析后得到的表面达到具有n×n对称性的稳定状态（饱和），n约为14。
