Theory of optical properties of quantum wires in porous silicon

Sanders, G. D.; Chang, Yia‐Chung

doi:10.1103/physrevb.45.9202

Cited by 338 publications

(124 citation statements)

References 12 publications

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“…In particular, [41] and [42] describe second neighbor empirical sp d s electronic bandstructure calculations in qualitative agreement with the results presented here, and [48] uses those results to compute transport properties.…”

Section: Discussionsupporting

confidence: 67%

Electronic Properties of Silicon Nanowires

Zheng

Rivas

Lake

et al. 2005

IEEE Trans. Electron Devices

181

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Section: Discussionsupporting

confidence: 67%

Electronic Properties of Silicon Nanowires

Zheng

Rivas

Lake

et al. 2005

IEEE Trans. Electron Devices

181

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“…Thus, the ab initio calculations suggest that all three SWSNTs are possibly metals. In contrast, for H-terminated 1D silicon nanowires, previous ab initio calculations (30)(31)(32)(33)(34) have shown that they possess wider band gap than that (1.17 eV) of cubic diamond silicon. The narrower the silicon nanowires, the wider their band gap.…”

mentioning

confidence: 75%

Metallic single-walled silicon nanotubes

Bai

Zeng²,

Tanaka³

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

129

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Atomistic computer-simulation evidences are presented for the possible existence of one-dimensional silicon nanostructures: the square, pentagonal, and hexagonal single-walled silicon nanotubes (SWSNTs). The local geometric structure of the SWSNTs differs from the local tetrahedral structure of cubic diamond silicon, although the coordination number of atoms of the SWSNTs is still fourfold. Ab initio calculations show that the SWSNTs are locally stable in vacuum and have zero band gap, suggesting that the SWSNTs are possibly metals rather than wide-gap semiconductors.L ow-dimensional nanostructures are known to have properties that can be markedly different from their bulk counterparts. For example, as shown in a recent experiment (1), Ho and coworkers demonstrated atom-by-atom evolution of electronic band structure of 1D gold chain. For semiconductor nanostructures, when the carriers (electrons and holes) are confined to dimensions less than their de Bröglie wavelength (typically a few nanometers), quantum-mechanical size effects can emerge. The carrier confinement at the nanoscale can be in 0D (quantum dots), 1D (quantum wires), or 2D (quantum wells) (2). Indeed, the current interest in fabricating low-dimensional semiconductor nanostructures, coined as band-structure engineering, has largely relied on novel quantum-mechanical size effects.The crystalline structure of 3D bulk silicon is cubic diamond, similar to that of carbon diamond. However, unlike the carbon counterpart (3), a 1D single-walled silicon nanotube (SWSNT) has not been found in nature yet, largely because silicon prefers sp 3 bonds rather than sp 2 bonds (4). Indeed, silicon has been viewed as nontubular solid rather than tubular solid, similar to carbon and boron nitride. The cubic diamond silicon is known as a semiconductor with an energy band gap of 1.17 eV (1 eV ϭ 1.602 ϫ 10 Ϫ19 J). At high pressures, however, the cubic-diamondstructured silicon can undergo a phase transformation to highly coordinated (sixfold or above) metallic phases such as the ␤-tin and hexagonal closed-packed structures (5). To date, experimentally produced 1D-like nanostructures of silicon [e.g., porous silicon (6) and silicon nanowires (7-12)] all assume either the cubic diamond crystalline structure or the local structure of amorphous silicon. A commonly reported electronic property of the 1D silicon nanostructures is that they all have wider band gap than the cubic diamond silicon. Here we present atomistic computer-simulation evidences of three thinnest SWSNTs: the square, pentagonal, and hexagonal silicon nanotubes. The local geometric structure of these SWSNTs differs from that of cubic diamond silicon and the surface-passivated 1D silicon nanowires. It also differs from that of the carbon-nanotube-like ''hypothetical'' SWSNTs (4, 13-15), because the latter types of SWSNTs are composed of both sp 3 and sp 2 bonds. Moreover, ab initio quantum-mechanical calculations show that the present SWSNTs exhibit an entirely opposite trend in the band-gap change compared wi...

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“…Theoretical and experimental studies show that as the dimension of crystalline Si domains is reduced to a few nanometers, many of the optical and electronic transport properties are modified due to the confinement. [16][17][18] Likewise, molecular dynamics simulations have also shown that, for these small domains, the thermal conductivities could be even two orders of magnitude smaller than that of bulk silicon. 19 Nevertheless, in spite of the importance to understand the underlying transport physics in silicon NWs and their application in nanodevices, to the best of our knowledge, very little attention has been paid on the effect of structural peculiarities at the nanoscale of Si NWs on the measured properties.…”

Section: Introductionmentioning

confidence: 99%

Influence of the (111) twinning on the formation of diamond cubic/diamond hexagonal heterostructures in Cu-catalyzed Si nanowires

Arbiol

Morral

Estradé

et al. 2008

Journal of Applied Physics

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The occurrence of heterostructures of cubic silicon/hexagonal silicon as disks defined along the nanowire ͗111͘ growth direction is reviewed in detail for Si nanowires obtained using Cu as catalyst. Detailed measurements on the structural properties of both semiconductor phases and their interface are presented. We observe that during growth, lamellar twinning on the cubic phase along the ͗111͘ direction is generated. Consecutive presence of twins along the ͗111͘ growth direction was found to be correlated with the origin of the local formation of the hexagonal Si segments along the nanowires, which define quantum wells of hexagonal Si diamond. Finally, we evaluate and comment on the consequences of the twins and wurtzite in the final electronic properties of the wires with the help of the predicted energy band diagram.

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Theory of optical properties of quantum wires in porous silicon

Cited by 338 publications

References 12 publications

Electronic Properties of Silicon Nanowires

Electronic Properties of Silicon Nanowires

Metallic single-walled silicon nanotubes

Influence of the (111) twinning on the formation of diamond cubic/diamond hexagonal heterostructures in Cu-catalyzed Si nanowires

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