Atomic Structural Analysis of Nanowire Defects and Polytypes Enabled Through Cross‐Sectional Lattice Imaging

Hemesath, Eric R.; Schreiber, Daniel K.; Kisielowski, Christian; Petford‐Long, Amanda K.; Lauhon, Lincoln J.

doi:10.1002/smll.201102404

Cited by 17 publications

(21 citation statements)

References 33 publications

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“…As a matter of fact, as shown by Arbiol2324 and Lopez19, different hexagonal polytypes, originating from the periodic ordering of stacking faults along the [111] irection, can coexist in the same wire. These structures also can be responsible of the experimental TEM observation we report on in this work25.…”

Section: Resultssupporting

confidence: 53%

Visible and Infra-red Light Emission in Boron-Doped Wurtzite Silicon Nanowires

Fabbri

Rotunno

Lazzarini

et al. 2014

Sci Rep

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Silicon, the mainstay semiconductor in microelectronic circuitry, is considered unsuitable for optoelectronic applications owing to its indirect electronic band gap, which limits its efficiency as a light emitter. Here we show the light emission properties of boron-doped wurtzite silicon nanowires measured by cathodoluminescence spectroscopy at room temperature. A visible emission, peaked above 1.5 eV, and a near infra-red emission at 0.8 eV correlate respectively to the direct transition at the Γ point and to the indirect band-gap of wurtzite silicon. We find additional intense emissions due to boron intra-gap states in the short wavelength infra-red range. We present the evolution of the light emission properties as function of the boron doping concentration and the growth temperature.

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Section: Resultssupporting

confidence: 53%

Visible and Infra-red Light Emission in Boron-Doped Wurtzite Silicon Nanowires

Fabbri

Rotunno

Lazzarini

et al. 2014

Sci Rep

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show abstract

“…The SAED patterns are indexed for Si [111] zone axis, implying the growth occurs in the ] 10 1 [ orientation. The white line-shaped patterns also indicate defects of micro-twin or stacking faults, [150] which is also consistent with the white shining lines directly observed in the dark Si side. As shown in Fig.…”

Section: Side-by-side Biaxial Nanowiressupporting

confidence: 82%

“…It is noted that the line-shaped spots pointed out by the dotted circles imply the existence of the defects. They could be either micro-twin or stacking faults, [150] requiring further atom-resolved observation to confirm. Fig.…”

Section: Side-by-side Biaxial Nanowiresmentioning

confidence: 99%

Growth mechanism of silicon nanowires from nickel-coated silicon wafer

Li¹

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Crystalline silicon (Si) nanowires are important building blocks in devices of photonics, quantum-dots, optoelectronics, and energy. Thermal annealing of metalcovered Si wafers gives rise to clean Si nanowires without metallic catalyst at the tip. The process does not need flammable or toxic gases. However, the growth mechanism is yet elucidated. This project grows Si nanowires by adopting the thermal annealing method: nickel (Ni) is sputtered on Si wafers as catalyst and thereafter a layer of carbon is sputtered to protect Si nanowires from oxidation during thermal annealing. Careful studies via transmission electron microscopy and selected area electron diffraction patterns elucidate the growth process and the relationship between the seeding Ni particle and the grown Si nanowire. The seeding Ni particles are embedded in the Ni-Si-O nanoclusters that are connected with the grown Si nanowires at the end of the nanowire growth. The growth orientation of Ni-seeded Si nanowires is not dictated by surface energy of the various nanocrystal planes, but follows specific structure sensitive principle with the seeding Ni nanoparticles to minimize the mismatch in lattice spacing and dihedral angle at the wire/particle interface. It is inferred that the growth orientation of Si nanowires is determined by the ordered planes of the Ni catalyst particle at the wire/particle interface. The various morphologies of the nanowires are controlled by the diameter and vibration of the Ni-Si-O droplet, the distribution of the Ni-Si, Ni-Si-O y (y≈1) and Ni-Si-O x (x≈2) phases, and the supersaturated content in the Ni-Si-O droplet. III ACKNOWLEDGEMENT I wish to deliver my most sincere and deepest gratitude to my supervisor Prof. Sam Zhang Shanyong for his effective academic advisory, continuous guidance and endless patience. Without his encouragement and care, I can't finish this tough work. I owe sincere thanks to Ms. Guo Jun and Mr. Kong Junhua from School of Material Science Engineering for their characterization assistance and constructive suggestions. Sincere thanks to all the researchers in Prof. Sam Zhang's group for their helpful discussions, suggestions and timely assistance.

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“…So far, transmission electron microscopy (TEM) has been one major technique commonly used to characterize the structure of individual 1D nanostructures and reveal the nature of planar defects [6]. However, due to the sophistication of the TEM technique, sometimes, experimental artifacts could be erroneously interpreted or lead to controversy [6-10]. To date, most planar defect-related studies have been focused on 1D nanostructures made of silicon, silicon carbide, III-V (e.g .…”

Section: Introductionmentioning

confidence: 99%

Observation of ‘hidden’ planar defects in boron carbide nanowires and identification of their orientations

et al. 2014

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The physical properties of nanostructures strongly depend on their structures, and planar defects in particular could significantly affect the behavior of the nanowires. In this work, planar defects (twins or stacking faults) in boron carbide nanowires are extensively studied by transmission electron microscopy (TEM). Results show that these defects can easily be invisible, i.e., no presence of characteristic defect features like modulated contrast in high-resolution TEM images and streaks in diffraction patterns. The simplified reason of this invisibility is that the viewing direction during TEM examination is not parallel to the (001)-type planar defects. Due to the unique rhombohedral structure of boron carbide, planar defects are only distinctive when the viewing direction is along the axial or short diagonal directions ([100], [010], or 1true¯10) within the (001) plane (in-zone condition). However, in most cases, these three characteristic directions are not parallel to the viewing direction when boron carbide nanowires are randomly dispersed on TEM grids. To identify fault orientations (transverse faults or axial faults) of those nanowires whose planar defects are not revealed by TEM, a new approach is developed based on the geometrical analysis between the projected preferred growth direction of a nanowire and specific diffraction spots from diffraction patterns recorded along the axial or short diagonal directions out of the (001) plane (off-zone condition). The approach greatly alleviates tedious TEM examination of the nanowire and helps to establish the reliable structure–property relations. Our study calls attention to researchers to be extremely careful when studying nanowires with potential planar defects by TEM. Understanding the true nature of planar defects is essential in tuning the properties of these nanostructures through manipulating their structures.

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Atomic Structural Analysis of Nanowire Defects and Polytypes Enabled Through Cross‐Sectional Lattice Imaging

Cited by 17 publications

References 33 publications

Visible and Infra-red Light Emission in Boron-Doped Wurtzite Silicon Nanowires

Visible and Infra-red Light Emission in Boron-Doped Wurtzite Silicon Nanowires

Growth mechanism of silicon nanowires from nickel-coated silicon wafer

Observation of ‘hidden’ planar defects in boron carbide nanowires and identification of their orientations

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