arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1909.07906cond-mat.mtrl-sci
收藏

在GaAs(111)纳米柱上应变驱动的InAs岛生长

Strain-driven InAs island growth on top of GaAs(111) nanopillars

T. Riedl, V. S. Kunnathully, A. Trapp, T. Langer, D. Reuter, J. K. N. Lindner

摘要:

我们从实验和理论上分析了圆柱形GaAs(111)A纳米柱上异质外延InAs岛的形状和位置。在低温下在GaAs纳米柱上无催化剂的分子束外延生长InAs导致直径< 30 nm的InAs岛呈现主要为圆形三角形的面内形状。岛显示出在从中心向柱边缘移位的位置处生长的趋势。原子分子静力学模拟的证据表明,三角形棱柱形的岛屿中心的支柱轴直径小于纳米柱的大力青睐。此外,我们揭示了离轴岛位置的最低能量状态的存在,与实验一致。这些发现被解释通过评估的空间应变分布和表面原子的断裂键的数量作为表面能的措施。优选的离轴岛位置可以根据岛下方的GaAs纳米柱的增加的顺应性来理解,因为自由表面的附近,导致应变能的降低。同时讨论了表面台阶对系统能量的影响。

英文摘要:

We analyze the shape and position of heteroepitaxial InAs islands on the top face of cylindrical GaAs(111)A nanopillars experimentally and theoretically. Catalyst-free molecular beam epitaxial growth of InAs at low temperatures on GaAs nanopillars results in InAs islands with diameters < 30 nm exhibiting predominantly rounded triangular in-plane shapes. The islands show a tendency to grow at positions displaced from the center towards the pillar edge. Atomistic molecular statics simulations evidence that triangular-prismatic islands centered to the pillar axis with diameters smaller than that of the nanopillars are energetically favored. Moreover, we reveal the existence of minimum-energy states for off-axis island positions, in agreement with the experiment. These findings are interpreted by evaluating the spatial strain distributions and the number of broken bonds of surface atoms as a measure for the surface energy. The preferred off-axis island positions can be understood in terms of an increased compliancy of the GaAs nanopillar beneath the island because of the vicinity of free surfaces, leading to a reduction of strain energy. The influence of surface steps on the energy of the system is addressed as well.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑