Polycrystalline tubular nanostructures of germanium

Mei, Yongfeng; Siu, G. G.; Li, Z.M.; Fu, Ricky K.Y.; Tang, Zikang; Chu, Paul K.

doi:10.1016/j.jcrysgro.2005.08.029

Cited by 6 publications

(3 citation statements)

References 24 publications

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“…Many 1D materials, including CNTs [2], SiNWs [5], germanium (Ge) NWs [12], zinc oxide NWs [16], and tungsten oxide NWs [17], are regarded as highly promising candidates for field emitters. 1D GeNSs, such as NWs [10][11][12], nanorods [18], nanocones [19], and nanotubes [20] have been grown by vapor-liquid-solid (VLS) [11,21,22], vapor-solid (VS) [23], vapor-solidsolid [24], solution-liquid-solid [25], template-assisted growth [26], and oxide-assisted growth (OAG) routes [27]. A summary of synthesis methods for some GeNSs is listed in table S1 (available at stacks.iop.org/Nano/21/455601/ mmedia).…”

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confidence: 99%

One-dimensional germanium nanostructures—formation and their electron field emission properties

Wu¹,

Hou²,

Chueh³

et al. 2010

Nanotechnology

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Ge nanostructures were synthesized by reduction of GeO(2) in H(2) atmosphere at various temperatures. Entangled and straight Ge nanowires with oxide shells were grown at high temperatures. Ge nanowires with various numbers of nodules were obtained at low temperatures. Ge nanowires without nodules exhibited remarkable field emission properties with a turn-on field of 4.6 V µm(-1) and field enhancement factor of 1242.

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confidence: 99%

One-dimensional germanium nanostructures—formation and their electron field emission properties

Wu¹,

Hou²,

Chueh³

et al. 2010

Nanotechnology

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“…While the growth techniques and mechanisms of GeNWs are relatively well understood, studies on Ge-based nanotubes are not as extensive. Most reported growths of Ge-based nanotubes are based on the vapor adsorption on templated nanostructures such as porous anodic alumina and carbon nanotubes (CNTs) . A self-assembly type approach to the growth of Ge-based nanotubes remains difficult.…”

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confidence: 99%

From Germanium Nanowires to Germanium−Silicon Oxide Nanotubes: Influence of Germanium Tetraiodide Precursor

et al. 2009

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Growth of semiconductor nanowires has attracted immense attention in the field of nanotechnology as nanowires are viewed as the potential basic building blocks of future electronics. The recent renewed interest in germanium as a material for nanostructures can be attributed to its higher carrier mobility and larger Bohr radius as compared to silicon. Self-assembly synthesis of germanium nanowires (GeNWs) is often obtained through a vapor-liquid-solid mechanism, which is essentially a catalytic tip-growth process. Here we demonstrate that by introducing an additional precursor, germanium tetraiodide (GeI(4)), in a conventional furnace system that produces GeNWs on silicon, tubular structures of germanium-silicon (GeSi) oxide can be obtained instead. Incorporation of GeI(4) results in passivation of the metal catalyst, preventing the occurrence of supersaturation, a prerequisite for the catalytic tip growth. We infer that passivation of the metal catalyst impedes Ge incorporation into the catalyst, leaving the catalyst rim as the only active sites for nucleation of both Si and Ge and thus resulting in the growth of GeSi oxide nanotubes via a root-growth process.

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“…Ge has regained significant interest in the research community due to its high carrier mobility, making it as a candidate material for high speed nanoelectronics applications. , The controlled synthesis of anisotropic semiconductor nanostructures is promising for the next generation electronics and photonics devices . Moreover, various Ge nanostructures like nanowires, − nanospikes, nanorods, nanotubes, nanoislands, and nanodots, , have been synthesized successfully. The morphological changes in nanostructures are well-known contributors for tuning their properties, which are being investigated intensively.…”

Section: Introductionmentioning

confidence: 99%

Chromium-Doped Germanium Nanotowers: Growth Mechanism and Room Temperature Ferromagnetism

Katkar

Chu

et al. 2011

Crystal Growth & Design

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The growth of high density germanium (Ge) nanostructures (nanowires and nanotowers) and influence of chromium (Cr) doping on its morphology have been investigated. It is observed that in the absence of Cr, Ge nanowires (NWs) are formed whereas the presence of Cr leads to the growth of Ge nanotowers (NTrs), wherein all other experimental parameters were kept constant. Independent of the Cr concentration, the crystal structures of both nanostructures, that is, NWs and NTrs, are identical. Traditional vapor–liquid–solid (VLS) process was used to explain the growth mechanism of the top of the Ge NTr, consisting of a thin nanowire with a gold tip. The bottom of the NTr consists of lateral (111) and (001) planes of polygonal structure; VLS process along with vapor-solid (VS) process accounts for its further growth. The mechanism for the dopant-dependent morphological changes in Ge nanostructures is clarified. The magnetic properties of the NTrs were probed using a superconducting quantum interference device (SQUID). Room-temperature ferromagnetism in Cr-doped Ge nanotowers was discovered. These findings can thus be exploited for controlling the morphology and generating the magnetic ordering in nonmagnetic semiconductors to develop stabilized novel spintronics devices.

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Polycrystalline tubular nanostructures of germanium

Cited by 6 publications

References 24 publications

One-dimensional germanium nanostructures—formation and their electron field emission properties

One-dimensional germanium nanostructures—formation and their electron field emission properties

From Germanium Nanowires to Germanium−Silicon Oxide Nanotubes: Influence of Germanium Tetraiodide Precursor

Chromium-Doped Germanium Nanotowers: Growth Mechanism and Room Temperature Ferromagnetism

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