Shandyba Nikita, Kirichenko Danil, Sharov Vladislav, Chernenko Natalia, Balakirev Sergey, Solodovnik Maxim
Laboratory of Epitaxial Technologies, Southern Federal University, Taganrog 347922, Russia.
Laboratory of Renewable Energy Sources, Alferov University, Saint Petersburg 194021, Russia.
Nanotechnology. 2023 Aug 29;34(46). doi: 10.1088/1361-6528/acee84.
We reveal a novel phenomenon observed after self-catalytic growth of GaAs nanowires (NWs) on Si(111) substrates treated with a Ga focused ion beam (FIB). Depending on the ion dose, NW arrays with various geometrical parameters can be obtained. A minor treatment of the substrate enables a slight increase in the surface density of NWs relative to an unmodified substrate area. As the ion dose is increased up to ∼0.1 pCm, the growth of GaAs NWs and nanocrystals is suppressed. However, a further increase in the ion dose stimulates the crystal growth leading to the formation of extremely thin NWs (39 ± 5 nm) with a remarkably high surface density of up to 15m. Resting upon an analysis of the surface structure before and after stages of ion-beam treatment, ultra-high vacuum annealing and NW growth, we propose a mechanism underlying the phenomenon observed. We assume that the chemical interaction between embedded Ga ions and a native Si oxide layer leads either to the enhancement of the passivation properties of the oxide layer within FIB-modified areas (at low and middle ion doses), or to the etching of the passivating oxide layer by excess Ga atoms, resulting in the formation of pores (at high ion doses). Due to this behavior, local fabrication of GaAs NW arrays with a diverse range of characteristics can be implemented on the same substrate. This approach opens a new way for self-catalytic growth of GaAs NWs.
我们揭示了一种在经镓聚焦离子束（FIB）处理的Si(111)衬底上自催化生长砷化镓纳米线（NWs）后观察到的新现象。根据离子剂量，可以获得具有各种几何参数的NW阵列。对衬底进行轻微处理会使NW的表面密度相对于未改性的衬底区域略有增加。当离子剂量增加到约0.1 pCm时，砷化镓NW和纳米晶体的生长受到抑制。然而，离子剂量的进一步增加会刺激晶体生长，导致形成极细的NW（39±5 nm），其表面密度高达15m，显著增加。基于对离子束处理、超高真空退火和NW生长阶段前后表面结构的分析，我们提出了观察到的这一现象的潜在机制。我们假设嵌入的镓离子与原生二氧化硅层之间的化学相互作用要么导致FIB改性区域内氧化层的钝化性能增强（在低和中等离子剂量下），要么导致过量的镓原子蚀刻钝化氧化层，从而形成孔隙（在高离子剂量下）。由于这种行为，可以在同一衬底上实现具有各种特性的砷化镓NW阵列的局部制造。这种方法为砷化镓NW的自催化生长开辟了一条新途径。
