Solid State Physics, Lund University, Box 118, SE-221 00 Lund, Sweden.
Nano Lett. 2012 Jun 13;12(6):3200-6. doi: 10.1021/nl301185x. Epub 2012 Jun 4.
Heterostructure nanowires have many potential applications due to the avoidance of interface defects by lateral strain relaxation. However, most heterostructure semiconductor nanowires suffer from persistent interface compositional grading, normally attributed to the dissolution of growth species in the common alloy seed particles. Although progress has been made for some material systems, most binary material combinations remain problematic due to the interaction of growth species in the alloy. In this work we investigate the formation of interfaces in InAs-GaAs heterostructures experimentally and theoretically and demonstrate a technique to attain substantially sharper interfaces. We show that by pulsing the Ga source during heterojunction formation, In is pushed out before GaAs growth initiates, greatly reducing In carry-over. This procedure will be directly applicable to any nanowire system with finite nonideal solubility of growth species in the alloy seed particle and greatly improve the applicability of these structures in future devices.
由于横向应变量的弛豫避免了界面缺陷，异质结构纳米线具有许多潜在的应用。然而，大多数异质结构半导体纳米线都存在持久的界面成分梯度，这通常归因于生长物种在常见的合金种子颗粒中的溶解。尽管在一些材料系统中已经取得了进展，但由于合金中生长物种的相互作用，大多数二元材料组合仍然存在问题。在这项工作中，我们从实验和理论上研究了 InAs-GaAs 异质结构中界面的形成，并展示了一种获得更锐利界面的技术。我们表明，通过在异质结形成过程中脉冲 Ga 源，可以在 GaAs 生长开始之前将 In 推出，大大减少 In 的携带。该方法将直接适用于任何纳米线系统，这些系统中生长物种在合金种子颗粒中的非理想溶解度有限，并且可以大大提高这些结构在未来器件中的适用性。
