SiGe Nanowires Grown by LPCVD: Morphological and Structural Analysis

Rodrı́guez, A.; Sangrador, J.; Rodrı́guez, T.; Ballesteros, C.; Prieto, C.; Jiménez, J.

doi:10.1557/proc-1258-p05-05

Cited by 5 publications

(7 citation statements)

References 9 publications

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“…The Si NWs had been synthesized by the LPCVD technique at 400 °C for 30 minutes using Si 2 H 6 as precursor gas, with a flow ranging from 8 to 2 sccm. The H 2 flow was changed to achieve a total flow rate of 100 sccm and the total pressure was kept constant at 400 mTorr 14 .…”

Section: Methodsmentioning

confidence: 99%

Electrical, photoelectrical and morphological properties of ZnO nanofiber networks grown on SiO2 and on Si nanowires

et al. 2013

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ZnO nanofibre networks (NFNs) were grown by vapour transport method on Si-based substrates. One type of substrate was SiO 2 thermally grown on Si and another consisted of a Si wafer onto which Si nanowires (NWs) had been grown having Au nanoparticles catalysts. The ZnO-NFN morphology was observed by scanning electron microscopy on samples grown at 600 °C and 720 °C substrate temperature, while an focused ion beam was used to study the ZnO NFN/Si NWs/Si and ZnO NFN/SiO 2 interfaces. Photoluminescence, electrical conductance and photoconductance of ZnO-NFN was studied for the sample grown on SiO 2 . The photoluminescence spectra show strong peaks due to exciton recombination and lattice defects. The ZnO-NFN presents quasi-persistent photoconductivity effects and ohmic I-V characteristics which become nonlinear and hysteretic as the applied voltage is increased. The electrical conductance as a function of temperature can be described by a modified three dimensional variable hopping model with nanometer-ranged typical hopping distances.

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Section: Methodsmentioning

confidence: 99%

Electrical, photoelectrical and morphological properties of ZnO nanofiber networks grown on SiO2 and on Si nanowires

et al. 2013

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“…Either SiH 4 or Si 2 H 6 and GeH 4 were used as precursor gases, and Au metal droplets were used as catalysts. 21 Single Si NWs were grown at 470 C using Si 2 H 6 as a precursor, while the SiGe NWs (with a nominal Ge atomic fraction close to 0.1) were grown at 430 C. The carrier gas was H 2 , preserving for the different precursor flow ratios a total pressure of 400 mTorr all over the growth run. 21 Under these growth conditions, straight NWs with uniform diameters ranging from 30 to 100 nm were obtained.…”

Section: Experimental and Samplesmentioning

confidence: 99%

“…21 Single Si NWs were grown at 470 C using Si 2 H 6 as a precursor, while the SiGe NWs (with a nominal Ge atomic fraction close to 0.1) were grown at 430 C. The carrier gas was H 2 , preserving for the different precursor flow ratios a total pressure of 400 mTorr all over the growth run. 21 Under these growth conditions, straight NWs with uniform diameters ranging from 30 to 100 nm were obtained. A crucial issue concerns the HJ; in a previous work, the different growth approaches followed to achieve the matching between the SiGe and Si segments in the axially heterostructured NWs were discussed.…”

Section: Experimental and Samplesmentioning

confidence: 99%

“…In particular, high resolution TEM images of the HJ region of SiGe/Si HJs did not show structural discontinuities at the junction, nor stacking faults, or other structural defects. 21,22 It is claimed that in VLS growth, the abruptness of the HJ depends on the solubility of the atomic species in the catalyst metal. Due to the reservoir effect in the catalyst droplet once the precursor gas source is switched-off to shift to the composition of the next NW segment, the remaining atoms solved in the catalyst droplet continue to be deposited up to reaching a sub-saturation concentration.…”

Section: Experimental and Samplesmentioning

confidence: 99%

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Electromagnetic field enhancement effects in group IV semiconductor nanowires. A Raman spectroscopy approach

Pura

Anaya

Souto

et al. 2018

Journal of Applied Physics

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Semiconductor nanowires (NWs) are the building blocks of future nanoelectronic devices. Furthermore, their large refractive index and reduced dimension make them suitable for nanophotonics. The study of the interaction between nanowires and visible light reveals resonances that promise light absorption/scattering engineering for photonic applications. Micro-Raman spectroscopy has been used as a characterization tool for semiconductor nanowires. The light/nanowire interaction can be experimentally assessed through the micro-Raman spectra of individual nanowires. As compared to both metallic and dielectric nanowires, semiconductor nanowires add additional tools for photon engineering. In particular, one can grow heterostructured nanowires, both axial and radial, and also one could modulate the doping level and the surface condition among other factors than can affect the light/NW interaction. We present herein a study of the optical response of group IV semiconductor nanowires to visible photons. The study is experimentally carried out through micro-Raman spectroscopy of different group IV nanowires, both homogeneous and axially heterostructured (SiGe/Si). The results are analyzed in terms of the electromagnetic modelling of the light/nanowire interaction using finite element methods. The presence of axial heterostructures is shown to produce electromagnetic resonances promising new photon engineering capabilities of semiconductor nanowires.

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“…The as-grown NWs were sonicated in an ultrasonic bath and suspended in methanol; subsequently the NWs were deposited on an Al substrate by dropcasting. For more details onthe growth of these NWs see [21] and [22]. High resolution transmission electron microscopy (TEM) and energy dispersive x-ray (EDX) analyses of the HJ werecarried out.…”

Section: Experimental Description and Samplesmentioning

confidence: 99%

Local electric field enhancement at the heterojunction of Si/SiGe axially heterostructured nanowires under laser illumination

et al. 2016

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We present a phenomenon concerningelectromagnetic enhancement at the heterojunction region of axially heterostructured Si/SiGe nanowires when the nanowire is illuminated by a focused laser beam. The local electric field is sensed by micro Raman spectroscopy, which allowsthe enhancement of the Raman signal arising from the heterojunction region to be revealed; the Raman signal per unit volume increases at least tentimes with respect to the homogeneous Siand SiGe nanowire segments. In order to explore the physical meaning of this phenomenon, a threedimensional solution of the Maxwell equations of the interaction between the focused laser beam and the nanowire was carried out by finite element methods. A local enhancement of the electric field at the heterojunction was deduced.However, the magnitude of the electromagnetic field enhancement only approaches the experimental one when the free carriers are considered, showing enhanced absorption at the carrier depleted heterojunction region. The existence of this effect promises a way ofimprovingphoton harvesting using axially heterostructured semiconductor nanowires.

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SiGe Nanowires Grown by LPCVD: Morphological and Structural Analysis

Cited by 5 publications

References 9 publications

Electrical, photoelectrical and morphological properties of ZnO nanofiber networks grown on SiO2 and on Si nanowires

Electrical, photoelectrical and morphological properties of ZnO nanofiber networks grown on SiO2 and on Si nanowires

Electromagnetic field enhancement effects in group IV semiconductor nanowires. A Raman spectroscopy approach

Local electric field enhancement at the heterojunction of Si/SiGe axially heterostructured nanowires under laser illumination

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