van der Waals Epitaxy of InAs Nanowires Vertically Aligned on Single-Layer Graphene

Hong, Young June; Lee, Wi Hyoung; Wu, Yaping; Ruoff, Rodney S.; Fukui, Takashi

doi:10.1021/nl204109t

Cited by 122 publications

(142 citation statements)

References 28 publications

(46 reference statements)

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“…The absence of any catalyst droplet at the tip of the InAs NWs indicates that the NWs were grown by a catalyst-free mechanism. The catalyst-free growths of InAs as well as InGaAs NWs on graphitic substrates have also been reported by Hong et al and Mohseni et al using MOCVD [51,[167][168][169]. These successful growths of III-V NWs on different graphitic substrates open up for the development of new hybrid system where the unique properties of both NWs and graphene can be utilized for fabricating various novel devices.…”

Section: Nw Growth On Graphenementioning

confidence: 60%

Position-Controlled Uniform GaAs Nanowires on Silicon using Nanoimprint Lithography

et al. 2014

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This thesis deals with the growth of GaAs nanowires (NWs) by molecular beam epitaxy (MBE) using vapor-liquid-solid method on various substrates including GaAs(111)B, Si(111) and graphene. The growth of the NWs on GaAs substrates was carried out by Au-catalyzed technique, whereas the growths on Si and graphene substrates were carried out using self-catalyzed technique that has been the main focus of this thesis. The long-term goal of this work was to produce p-n radial junction GaAs NWs for solar cell applications.Necessary conditions were established for obtaining vertical self-catalyzed GaAs NWs on Si(111), which is reproducible from run-to-run. One of the major issues in these NWs grown by both Au-and self-catalyzed techniques is their crystal structure. The Au-catalyzed GaAs NWs usually adopt a wurtzite (WZ) crystal phase, whereas the self-catalyzed NWs a zinc blende (ZB) phase. However, in both the cases the NWs contain stacking faults, rotational twins or/and a mixed crystal phase. The ZB and WZ phases show different optical properties, and one phase might be favored over other for certain applications. Therefore the crystal phase was controlled within single NWs by tuning the V/III ratio and introducing GaAsSb inserts. The change of the crystal phases was correlated with the change in the contact angle of the Ga droplet.Since the discovery of graphene, an ultra-thin two-dimensional material, the research on graphene has become an active field in recent years due to its remarkable properties including excellent electrical and thermal conductivities, mechanical strength and flexibility, and optical transparency. By growing the semiconductor NWs on graphene, a completely new hybrid system can be envisioned where the unique properties of both NWs and graphene can be utilized. Therefore we established a method for the growth of semiconductor NWs on graphene by demonstrating epitaxial growth of vertical GaAs and InAs NWs on different graphitic substrates.Core-shell heterostructure, doping, optical properties, and position controlled growth of self-catalyzed GaAs NWs were investigated. Growth of GaAs/GaAsSb coreshell NWs where the Sb content was tuned from about 10% -70% was studied. The effect of growth temperature and the Sb flux on the morphology of GaAsSb shell was investigated. In addition, by utilizing the core-shell geometry where the shell copies the crystal phase of the core, WZ phase of GaAsSb was demonstrated. Successful p-type doping of GaAs core using Be as dopant, and n-type doping of GaAs shell using Si and Te as dopants were achieved. To investigate the optical properties, GaAs/AlGaAs coreshell NWs were grown with different V/III ratios during the core growth. The NWs grown with high V/III ratio, despite containing a higher density of twinned ZB and WZ GaAs with SFs, were found to have superior optical quality as compared to the NWs grown with low V/III ratio that contain pure ZB GaAs. The observed V/III ratio dependent optical quality was correlated to the intrinsic defects such as As vac...

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Section: Nw Growth On Graphenementioning

confidence: 60%

Position-Controlled Uniform GaAs Nanowires on Silicon using Nanoimprint Lithography

et al. 2014

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“…The d 100 interplanar spacing of CVD graphene layers and wurtzite InAs nanorods were 2.1 and 3.7 Å, respectively, which is in agreement with the previously reported values. 19,20 To examine the change in the lattice parameters during the initial growth stage, the evolution of RHEED intensities along the dotted lines in Figure 2b was plotted as a function of time in the combined images shown in the inset of Figure 2c. Inset (i) of Figure 2c clearly shows the 101l À Á Bragg spots of InAs that appeared abruptly with the initiation of growth (t = 0); the position of these spots did not change as growth progressed, implying that unstrained InAs nanorod crystals formed directly on CVD graphene layers, without a strain relaxation step.…”

Section: Catalystmentioning

confidence: 99%

“…22 For all azimuthal rotation angles, the RHEED patterns from the InAs nanorods were the same, indicating that the nanorods were vertically well aligned along [0002] WZ and [111] ZB , but their in-plane orientations were random; these results were attributed to in-plane misorientations of grains in the CVD graphene layers. 19,23 RHEED also enabled us to investigate the growth of In x Ga 1 − x As coaxial shell layers as well as InAs nanorods. For In x Ga 1 − x As coaxialshell layer growth, although the RHEED intensity decreased with growth time as the nanorod thickness increased, no significant change in the RHEED pattern was observed, as shown in Figures 2d and e.…”

Section: Catalystmentioning

confidence: 99%

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Catalyst-free growth of InAs/InxGa1−xAs coaxial nanorod heterostructures on graphene layers using molecular beam epitaxy

Tchoe

Kim

et al. 2015

NPG Asia Mater

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We report the catalyst-free growth of InAs/In x Ga 1 − x As coaxial nanorod heterostructures on large-area graphene layers using molecular beam epitaxy and our investigation of the chemical composition and crystal structure of these heterostructures using electron microscopy. The graphene layers used as the substrate were prepared by chemical vapor deposition and transferred onto SiO 2 /Si substrates. InAs nanorods and their heterostructures were grown vertically on the graphene layers; electron microscopy images revealed uniform distributions for their diameter, length and density. Cross-sectional electron microscopy images showed that In x Ga 1 − x As layers, having uniform composition, coated heteroepitaxially the entire surface of the InAs nanorods, without interfacial layers or structural defects. The catalyst-free growth mechanism of InAs nanorods on graphene was investigated using in situ reflection high-energy electron diffraction.

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“…InAs nanowire growth on single-layer graphene has also been reported. (43) Group III nitrides are good compounds for UV photodetectors because of their high thermal stability, wide bandgap, high breakdown voltage, and high photoresponsivity. (44,45) …”

Section: Iii-v Compoundsmentioning

confidence: 99%

A Review of Nanotechnology for Highly Sensitive Photodetectors for Vision Sensors of Insect-like Robots

2015

Sensors and Materials

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Insect-like robots for various purposes have been widely studied in recent years. Owing to the small size of the insect-like robots, reducing the size of the receptive field is an important subject. Furthermore, most insect-like robots are required to work at night as well as day. Therefore, an ultrahigh-sensitivity sensor with an ultrasmall size is essential for the realization of insect-like robots. A high photon-to-electron conversion efficiency above the limitation of conventional devices can be achieved in a nanostructure owing to its quantum effect. In this paper, we report on the fabrication methods and materials for making nanostructures, and introduce nanostructure photodetectors with an explanation of the principle of the quantum effect.

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van der Waals Epitaxy of InAs Nanowires Vertically Aligned on Single-Layer Graphene

Cited by 122 publications

References 28 publications

Position-Controlled Uniform GaAs Nanowires on Silicon using Nanoimprint Lithography

Position-Controlled Uniform GaAs Nanowires on Silicon using Nanoimprint Lithography

Catalyst-free growth of InAs/InxGa1−xAs coaxial nanorod heterostructures on graphene layers using molecular beam epitaxy

A Review of Nanotechnology for Highly Sensitive Photodetectors for Vision Sensors of Insect-like Robots

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