Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Zhou, Tong; Zhong, Zhenyang

doi:10.1063/1.4866356

Cited by 10 publications

(11 citation statements)

References 31 publications

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“…It has been found that surface energy is considerably influenced by the miscut angles. 21,31,41 The overall fact that the NW width is nearly not affected by the miscut angle indicates that the variation in surface energy is balanced by that in elastic energy due to the anisotropicity of the vicinal surface. Our results disclose that the elastic energy on the vicinal surface is also considerably affected by the miscut angle.…”

Section: Resultsmentioning

confidence: 99%

“…These are the main factors underlying the sensitive self-assembly of nanostructures on miscut substrates. 21,41 Next, we analyze the measurement of the wetting layers as a function of miscut angles. From a thermodynamic point of view, transition from a flat film to undulated surface occurs because elastic energy relaxation eventually overcomes the extra cost of creating an undulated surface during growth.…”

Section: Resultsmentioning

confidence: 99%

“…For example, on a normal Si (001) surface, hut clusters can be elongated to become NWs during thermal annealing. 17 On a vicinal Si (001) surface misoriented toward the <110> direction by several degrees, self-assembled GeSi nanostructures evolve from asymmetric-pyramid-like quantum dots (QDs) to NWs in the special case of the Si (1 1 10) surface, [18][19][20][21] whereas, in the former case, an extremely long annealing time is required. Moreover, the obtained GeSi NWs frequently intersect since the NWs can orient along either of the two perpendicular <100> directions.…”

Section: Introductionmentioning

confidence: 99%

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Unique features of laterally aligned GeSi nanowires self-assembled on the vicinal Si (001) surface misoriented toward the [100] direction

et al. 2015

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We demonstrate laterally aligned and catalyst-free GeSi nanowires (NWs) via self-assembly of Ge on miscut Si (001) substrates toward the [100] direction by an angle θ (θ < 11°). The NWs are bordered by (001) and (105) facets, which are thermodynamically stable. By tuning the miscut angle θ, the NW height can be easily modulated with a nearly constant width. The thickness of the wetting layer beneath the NWs also shows a peculiar behavior with a minimum at around 6°. An analytical model, considering the variation of both the surface energy and the strain energy of the epilayer on vicinal surfaces with the miscut angle and layer thickness, shows good overall agreement with the experimental results. It discloses that both the surface energy and stain energy of the epilayer on vicinal surfaces can be considerably affected in the same trend by the surface steps. Our results not only shed new light on the growth mechanism during heteroepitaxial growth, but also pave a prominent way to fabricate and meanwhile modulate laterally aligned and dislocation-free NWs.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Unique features of laterally aligned GeSi nanowires self-assembled on the vicinal Si (001) surface misoriented toward the [100] direction

et al. 2015

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“…Clearly, current researches mainly focus on the improvement of luminescence properties by acquiring quantum dots with high density, uniform sizes and other special structures. Zhou et al 71 observed a quite strong Photoluminescence (PL) peak of dense GeQDs on a miss-cut substrate even at 300 K, as shown in Fig. 9, which was attributed to the good con¯nement of excitons in dense GeQDs due to the absence of the wetting layer.…”

Section: Preparation and Structures Of Geqds On Planar Substratementioning

confidence: 95%

Review of the Preparation and Structures of Si Nanowires, Ge Quantum Dots and Their Composites

Weng

Yang

et al. 2019

NANO

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Because the motion of charge carriers in nanowires and quantum dots is restricted within nanoscale in two and three dimensions, respectively, both nanowires and quantum dots exhibit many excellent optoelectronic properties. Particularly, with the advantage of being compatible with Si integrated circuits, Silicon nanowires (SiNWs) and germanium quantum dots (GeQDs) have been extensively studied in the past few decades. In order to explore novel physical properties, the integration of SiNWs and GeQDs has attracted great attention recently. In this paper, recent researches on the preparation methods and structures of SiNWs, GeQDs and their composites are reviewed, respectively. The synthesis of SiNWs with random distribution and ordered arrays by using vapor–liquid–solid growth mechanism and metal-assisted chemical etching technique is firstly summarized. Some special structures of SiNWs are also discussed. Furthermore, the development of some novel structures of GeQDs for further improving their optical properties is reviewed. Finally, the growth mechanism and structure evolution of SiNWs/GeQDs composites are illustrated from the view of theory and experiment. The strain in Ge shell layers and SiNWs, the relationship between Ge growth mode and SiNW diameter, and the distribution of GeQDs on the radial and axial directions of SiNWs are discussed in detail. The research about the growth of SiNWs/GeQDs composite structures is in its early stage, so there are many questions that need to be resolved in future.

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“…The mechanism behind the formation and stability of these nanowires are attributed to abnormal faceting of the wetting layer [6, 13] or extended huts [10, 20], which is driven by the low surface energy of their {1 0 5} side facets under equilibrium phase. These lateral nanowires have shown potential applications for nano-electronics [10, 21], spintronic devices [22, 23], and optoelectronics [24, 25]. …”

Section: Introductionmentioning

confidence: 99%

Formation of Self-Connected Si0.8Ge0.2 Lateral Nanowires and Pyramids on Rib-Patterned Si(1 1 10) Substrate

Chen

Lü

2017

Nanoscale Res Lett

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In this work, Si0.8Ge0.2 is deposited onto the rib-patterned Si (1 1 10) template oriented in the [1 −1 0] direction. Atomic force microscopy (AFM) reveals that the rib sidewalls reshape into pyramid-covered (0 0 1) and smooth {1 1 3} facets, respectively, while the {1 0 5} facets-bounded lateral SiGe nanowires dominate the rib top along the [5 5 −1] direction. At both the rib shoulder sites and the pyramid vacancy sites, self-connecting occurs between the meeting nanowire and pyramids to form elongated huts, which are driven by the minimization of the total energy density according to the finite-element simulations results. These results suggest a convenient solution to form lateral SiGe nanowires covering multi-faceted surfaces on the patterned template.

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Dramatically enhanced self-assembly of GeSi quantum dots with superior photoluminescence induced by the substrate misorientation

Cited by 10 publications

References 31 publications

Unique features of laterally aligned GeSi nanowires self-assembled on the vicinal Si (001) surface misoriented toward the [100] direction

Unique features of laterally aligned GeSi nanowires self-assembled on the vicinal Si (001) surface misoriented toward the [100] direction

Review of the Preparation and Structures of Si Nanowires, Ge Quantum Dots and Their Composites

Formation of Self-Connected Si0.8Ge0.2 Lateral Nanowires and Pyramids on Rib-Patterned Si(1 1 10) Substrate

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