Dopant-stimulated growth of GaN nanotube-like nanostructures on Si(111) by molecular beam epitaxy

Abstract

In this paper we study growth of quasi-one-dimensional GaN nanowires (NWs) and nanotube (NT)-like nanostructures on Si(111) substrates covered with a thin AlN layer grown by means of plasma-assisted molecular beam epitaxy. In the first part of our study we investigate the influence of the growth parameters on the geometrical properties of the GaN NW arrays. First, we find that the annealing procedure carried out prior to deposition of the AlN buffer affects the elongation rate and the surface density of the wires. It has been experimentally demonstrated that the NW elongation rate and the surface density drastically depend on the substrate growth temperature, where 800 °C corresponds to the maximum elongation rate of the NWs. In the second part of the study, we introduce a new dopant-stimulated method for GaN nanotube-like nanostructure synthesis using a high-intensity Si flux. Transmission electron microscopy was used to investigate the morphological features of the GaN nanostructures. The synthesized structures have a hexagonal cross-section and possess high crystal quality. We propose a theoretical model of the novel nanostructure formation which includes the role of the dopant Si. Some of the Si-doped samples were studied with the photoluminescence (PL) technique. The analysis of the PL spectra shows that the highest value of donor concentration in the nanostructures exceeds 5∙1019 cm−3.

Growth and Characterization of GaP/GaPAs Nanowire Heterostructures with Controllable Composition

“…The problems of ternary alloys synthesis are well known for alloys with molar content x close to 0.5. Semiconductor nanowires (NWs) geometry provides unique ability to overcome the miscibility gap in lattice mismatched systems in comparison with planar structure, thus opening new ways for compounds functionalization and integration on mismatched substrates . Novel properties such as waveguiding behavior, optical cavity effects, and so on, can be realized in NW due to its morphology, making the NWs attractive as nanoscale light sources.…”

Рост нанотрубок и нитевидных нанокристаллов GaN с катализатором Au-Ni

“…Оптоэлектронные свойства нанотрубок и нитевидных нанокристаллов исследованы методами фото-и катодолюминесценции. Формирование жидких капель приводит к росту ННК по хорошо известному механизму пар−жидкость−кристалл [3, 5,12,14]. Так как капля все время смачивает верхнюю фасетку ННК, возникновение полости в центре невозможно, и образуются цельные ННК.…”

“…Рост с твердыми частицами катализатора тоже может приводить к формированию ННК, но по механизму пар−кристалл−кристалл [12,13]. Вследствие того что диффузия в этом случае идет не по всему объему катализатора, а только по поверхности кристалла [5,6], вместо ННК могут образовываться НТ [5], так как потоки галлия и азота по поверхности будут быстро уменьшаться от края к центру.…”

High Quality Growth of Cobalt Doped GaN Nanowires with Enhanced Ferromagnetic and Optical Response

“…1D structures of GaN have also been studied in recent years such as nanowires [37][38][39][40] and nanotubes [41,42]. Different dopants have been incorporated to optimize the physical proprieties of GaN based DMSs such as Mg [43][44][45], Mn [46], Fe [47], Cu [48], Si [49,50], Cr [51] and Tb [52], etc. However, the studies about Co-doped GaN nanowires are very few and even the existing results need to be optimized for a high Curie temperature, better structure, morphology, etc.…”