``Contact epitaxy'' observed in supported nanoparticles
``Contact epitaxy'' observed in supported nanoparticles
复制标题
DOI：
10.1063/1.122720
复制
发表时间：
1998-11
影响因子：
4
通讯作者：
M. Yeadon;M. Ghaly;J. C. Yang;R. Averback;J. Gibson
中科院分区：
文献类型：
--
作者：
M. Yeadon;M. Ghaly;J. C. Yang;R. Averback;J. Gibson
我们已经观察到异质外延界面层之间的形成银纳米粒子和单晶铜表面的现象，我们称之为“接触外延”。在真空原位透射电子显微镜中将Ag纳米颗粒（5-20 nm直径）沉积到干净的（001）Cu上后，在基底和颗粒之间的界面处检测到薄的（111）取向的Ag层。分子动力学模拟表明，外延层的影响皮秒内形成，与快速对齐所产生的机械松弛的高应力界面时形成的初始接触。模拟还表明，作为这种弛豫过程的结果，在纳米颗粒中形成多个晶粒。由接触外延引起的纳米颗粒的独特结构，预计将显着影响物理性质，如界面结合，扩散，化学活性和电输运，以及形成晶粒生长和外延生长的核。
We have observed the formation of heteroepitaxial interfacial layers between silver nanoparticles and a single crystal copper surface by a phenomenon we term “contact epitaxy.” Upon depositing Ag nanoparticles (5–20 nm diameter) onto clean (001) Cu in an ultrahigh vacuum in situ transmission electron microscope, a thin (111)-oriented layer of Ag was detected at the interface between the substrate and particles. Molecular dynamics simulations reveal that the epitaxial layers form within picoseconds of impact, with rapid alignment arising from mechanical relaxation of the highly stressed interface formed upon initial contact. The simulations also show that multiple grains form in the nanoparticle as a consequence of this relaxation process. The unique structure of the nanoparticles, induced by contact epitaxy, is expected to significantly influence physical properties such as interfacial bonding, diffusion, chemical activity, and electrical transport, as well as forming a nucleus for grain growth and epitax...