Influence of the oxide layer for growth of self-assisted InAs nanowires on Si(111)

Madsen, Morten Hannibal; Aagesen, Martin; Krogstrup, Peter; Sørensen, C. B.; Nygård, Jesper

doi:10.1186/1556-276x-6-516

Cited by 32 publications

(32 citation statements)

References 24 publications

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“…The absence of metal droplets on the top of NWs is similar to the InAs NWs grown on Si by MBE which was ascribed to vapour-solid (VS) growth mechanism [20-22]. As the growth conditions of our NWs are similar, we assume that our NW growth also follows a VS mechanism.…”

Section: Resultssupporting

confidence: 69%

Graphitic platform for self-catalysed InAs nanowires growth by molecular beam epitaxy

et al. 2014

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We report the self-catalysed growth of InAs nanowires (NWs) on graphite thin films using molecular beam epitaxy via a droplet-assisted technique. Through optimising metal droplets, we obtained vertically aligned InAs NWs with highly uniform diameter along their entire length. In comparison with conventional InAs NWs grown on Si (111), the graphite surface led to significant effects on the NWs geometry grown on it, i.e. larger diameter, shorter length with lower number density, which were ascribed to the absence of dangling bonds on the graphite surface. The axial growth rate of the NWs has a strong dependence on growth time, which increases quickly in the beginning then slows down after the NWs reach a length of approximately 0.8 μm. This is attributed to the combined axial growth contributions from the surface impingement and sidewall impingement together with the desorption of adatoms during the diffusion. The growth of InAs NWs on graphite was proposed following a vapour-solid mechanism. High-resolution transmission electron microscopy reveals that the NW has a mixture of pure zinc-blende and wurtzite insertions.

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Section: Resultssupporting

confidence: 69%

Graphitic platform for self-catalysed InAs nanowires growth by molecular beam epitaxy

et al. 2014

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“…Usually, a native oxide layer of ~1.5 nm exists on the surface of the Si (111) substrate. [19][20][21] The hardness of the SiO 2 layer (~2.0 GPa 22 ) is much smaller than that of the Si (111) substrate (~11.5 GPa 21 ), and thus the oxide layer can be sheared easily and the initial friction coefficientis small. When the native 10 oxide layer is worn out, the friction coefficient increases.…”

Section: Film Characterizationmentioning

confidence: 99%

Friction mechanism of zinc oxide films prepared by atomic layer deposition

Chai

2015

RSC Adv.

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5Friction and wear can make the normal operation of zinc oxide (ZnO) films in many devices impracticable. In this paper, the friction mechanism of ZnO films was studied. The ZnO films were prepared by atomic layer deposition (ALD) on a Si (111) substrate, and the crystal structure of the films was controlled by adjusting the substrate temperature. The surface morphology, microstructure and composition of the ZnO films were studied by a scanning probe microscopy (SPM), a 10 transmissionelectron microscopy (TEM) and an Auger electron microscopy (AES), respectively. The friction coefficient of the ZnO films was measured by a ball-on-disk tester. The results show that the ZnO film deposited at 300 °C has lager crystal size than that deposited at 150 °C. In addition, the 300 °C deposited ZnO film consists of mainly (002)-textured nanocrystal, while the 150 °C deposited ZnO film consists of other orientational nanocrystal, such as (100) and (101)-textured nanocrystals. The friction 15 coefficient of the ZnO films is ~0.1, much smaller than 0.6 of the Si (111) substrate. Low friction coefficient is attributed to plastic deformation induced nanocrystal structure to amorphous structure transformation. The 150 °C deposited ZnO film has smaller crystal size than the 300 °C deposited ZnO film, and thus deformation more easily and the friction coefficient is smaller. 20 65 sliding tester. In order to make clear the mechanism of the improved tribological property of ZnO films, site selective TEM samples were prepared inside the wear track. ExperimentalThis journal is

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“…However, both sputtered and further etched as well as native oxides can vary in thickness and quality over the sample resulting in inhomogeneous NW growth as observed for InAs NWs in Ref. [10]. With this respect, highly reproducible oxide layers are required.…”

Section: Introductionmentioning

confidence: 96%