Hijazi Hadi, Zeghouane Mohammed, Jridi Jihen, Gil Evelyne, Castelluci Dominique, Dubrovskii Vladimir G, Bougerol Catherine, André Yamina, Trassoudaine Agnès
ITMO University, Kronverkskiy pr. 49, 197101 St. Petersburg, Russia.
Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France.
Nanotechnology. 2021 Apr 9;32(15):155601. doi: 10.1088/1361-6528/abdb16.
Controlled growth of In-rich InGaN nanowires/nanorods (NRs) has long been considered as a very challenging task. Here, we present the first attempt to fabricate InGaN NRs by selective area growth using hydride vapor phase epitaxy. It is shown that InGaN NRs with different indium contents up to 90% can be grown by varying the In/Ga flow ratio. Furthermore, nanowires are observed on the surface of the grown NRs with a density that is proportional to the Ga content. The impact of varying the NH partial pressure is investigated to suppress the growth of these nanowires. It is shown that the nanowire density is considerably reduced by increasing the NH content in the vapor phase. We attribute the emergence of the nanowires to the final step of growth occurring after stopping the NH flow and cooling down the substrate. This is supported by a theoretical model based on the calculation of the supersaturation of the ternary InGaN alloy in interaction with the vapor phase as a function of different parameters assessed at the end of growth. It is shown that the decomposition of the InGaN solid alloy indeed becomes favorable below a critical value of the NH partial pressure. The time needed to reach this value increases with increasing the input flow of NH, and therefore the alloy decomposition leading to the formation of nanowires becomes less effective. These results should be useful for fundamental understanding of the growth of InGaN nanostructures and may help to control their morphology and chemical composition required for device applications.
长期以来，富铟氮化铟镓纳米线/纳米棒（NRs）的可控生长一直被认为是一项极具挑战性的任务。在此，我们首次尝试通过氢化物气相外延选择性区域生长法制备氮化铟镓纳米棒。结果表明，通过改变铟/镓流量比，可以生长出铟含量高达90%的不同氮化铟镓纳米棒。此外，在生长的纳米棒表面观察到纳米线，其密度与镓含量成正比。研究了改变NH分压对抑制这些纳米线生长的影响。结果表明，通过增加气相中的NH含量，纳米线密度显著降低。我们将纳米线的出现归因于停止NH气流并冷却衬底后发生的生长最后阶段。基于生长结束时评估的不同参数，通过计算三元氮化铟镓合金与气相相互作用的过饱和度建立的理论模型支持了这一点。结果表明，在NH分压低于临界值时，氮化铟镓固态合金的分解确实变得有利。达到该值所需的时间随着NH输入流量的增加而增加，因此导致纳米线形成的合金分解变得不那么有效。这些结果对于深入理解氮化铟镓纳米结构的生长应该是有用的，并且可能有助于控制其形态和器件应用所需的化学成分。
