Raman spectroscopy and strain mapping in individual<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mtext>Ge-Si</mml:mtext><mml:mi>x</mml:mi></mml:msub></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mtext>Ge</mml:mtext><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:math>core-shell nanowires

Dillen, David C.; Varahramyan, K.; Corbet, Chris M.; Tutuc, Emanuel

doi:10.1103/physrevb.86.045311

Cited by 28 publications

(30 citation statements)

References 38 publications

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“…In particular, new terms arise in the corresponding strain and stress tensors that are absent in homogeneous NWs. We illustrate our results via the example of Ge/Si NWs, given the fact that the coherence of their interfaces has already been demonstrated experimentally [41,42]. The derived formulas for the static strain can be considered a further extension of those listed in Ref.…”

Section: Introductionmentioning

confidence: 61%

Acoustic phonons and strain in core/shell nanowires

2014

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We study theoretically the low-energy phonons and the static strain in cylindrical core/shell nanowires (NWs). Assuming pseudomorphic growth, isotropic media, and a force-free wire surface, we derive algebraic expressions for the dispersion relations, the displacement fields, and the stress and strain components from linear elasticity theory. Our results apply to NWs with arbitrary radii and arbitrary elastic constants for both core and shell. The expressions for the static strain are consistent with experiments, simulations, and previous analytical investigations; those for phonons are consistent with known results for homogeneous NWs. Among other things, we show that the dispersion relations of the torsional, longitudinal, and flexural modes change differently with the relative shell thickness, and we identify new terms in the corresponding strain tensors that are absent for uncapped NWs. We illustrate our results via the example of Ge/Si core/shell NWs and demonstrate that shell-induced strain has large effects on the hole spectrum of these systems.

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Section: Introductionmentioning

confidence: 61%

Acoustic phonons and strain in core/shell nanowires

2014

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“…Assuming a coherently strained core-shell NW [36] and the effect of the elastic strain on the energy bands [37], we calculate a Ge-Si 1-x Ge x conduction band offset of −0.19 eV. Consequently, the inversion charges are mostly in the Si 1-x Ge x shell, near the dielectric/NW interface, and are subject to increased surface roughness and fixed interface charge scattering.…”

Section: Device Characterization and Scaling Propertiesmentioning

confidence: 99%

Realization and Scaling of ${\rm Ge}{\hbox{--}}{\rm Si}_{1{\hbox{-}}{\rm x}}{\rm Ge}_{\rm x}$ Core-Shell Nanowire $n$-FETs

Liu

Dillen

Nah

et al. 2013

IEEE Trans. Electron Devices

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We present the realization and scaling properties of germanium-silicon-germanium (Ge-Si 1-x Ge x ) core-shell nanowire (NW) n-type, -gate field-effect transistors (FETs). The devices show superior performance to the counterparts without the Si 1-x Ge x shell. With a channel length (L ch ) of 380 nm and a diameter of 40 nm, we demonstrate a subthreshold swing of 180 mV/dec, and an ON-current (I ON ) of 60 μA/μm, comparable with recent results in Ge n-type FinFETs fabricated by top-down techniques. By systematically studying the scaling properties, we identify the contribution of the channel and contact resistances to device characteristics. We conclude that I ON is not limited by the contact resistance but rather by a relatively large channel resistance, presumably associated with a high-interface trap density ( D i t ).

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“…Up until now, most of the research effort has been focused on homogeneous NWs; however, heterostructured NWs are necessary for the fabrication of advanced devices. Some effort has been focused on core/shell heterostructured NWs, mainly focused on the stress assessment, but much less effort has been devoted to the optical properties of axially heterostructured NWs.…”

Section: Introductionmentioning

confidence: 99%

About the Interaction Between a Laser Beam and Group IV Nanowires: A Study of the Electromagnetic Field Enhancement in Homogeneous and Heterostructured Nanowires

Pura

Anaya

Jiménez

2018

Physica Status Solidi (a)

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The optical properties of semiconductor nanowires (NWs) are object of study because they are the building blocks of the future nanophotonic devices. The high refractive index and its reduced dimension, make them suitable for photon engineering. The study of the interaction between NWs and visible light has revealed resonances of the light absorption/scattering by the NWs. Micro‐Raman spectroscopy is used as a characterization method of semiconductor NWs. The relation between the Raman intensity and the incident electromagnetic (EM) field permits to study the light/NW interaction through the micro‐Raman spectra of individual NWs. As compared to either metallic or dielectric NWs, the semiconductor NWs add additional tools to modify its interaction with light, for example, the composition, the presence of heterostructures, both axial and radial, doping, and the surface morphology. One presents herein a study of the optical response of group IV semiconductor NWs to visible photons. The study is experimentally carried out through the micro‐Raman spectroscopy of different group IV NWs, both homogeneous and heterostructured (SiGe/Si), and the results are analyzed in terms of the EM modeling of the light/NW interaction using finite element methods (FEMs). The heterostructures are seen to produce additional resonances allowing new photonic capacities to the semiconductor NWs.

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Raman spectroscopy and strain mapping in individualGe-SixGe1−xcore-shell nanowires

Cited by 28 publications

References 38 publications

Acoustic phonons and strain in core/shell nanowires

Acoustic phonons and strain in core/shell nanowires

Realization and Scaling of ${\rm Ge}{\hbox{--}}{\rm Si}_{1{\hbox{-}}{\rm x}}{\rm Ge}_{\rm x}$ Core-Shell Nanowire $n$-FETs

About the Interaction Between a Laser Beam and Group IV Nanowires: A Study of the Electromagnetic Field Enhancement in Homogeneous and Heterostructured Nanowires

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