Lithography-free oxide patterns as templates for self-catalyzed growth of highly uniform GaAs nanowires on Si(111)

Hakkarainen, Teemu; Schramm, Andreas; Mäkelä, Jarno; Laukkanen, P.; Guina, Mircea

doi:10.1088/0957-4484/26/27/275301

Cited by 33 publications

(38 citation statements)

References 47 publications

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“…The Al 0.3 Ga 0.7 As shell and GaAs supershell were then grown around the NW core using growth conditions that promote radial growth. The details of the Si/SiOx pattern fabrication and NW growth are explained in more detail in 29 and in Supporting information (1-2), which includes also the description of the shell layer growth and characterization of the coaxial heterostructure (Fig. S2-S3 and Table S1).…”

Section: Methodsmentioning

confidence: 99%

“…However, the absorption measurements that would provide the detection of the resonant NW behaviour and therefore direct detection of discrete waveguide modes are still lacking. In this work we used the photo-acoustic spectroscopy (PAS) technique to study absorbance properties of GaAs-AlGaAs heterostructure NWs grown by self-catalyzed technique on lithography-free Si/SiOx patterns 29 .…”

Section: Introductionmentioning

confidence: 99%

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Photo-acoustic spectroscopy revealing resonant absorption of self-assembled GaAs-based nanowires

Leahu

Petronijevic

Belardini

et al. 2017

Sci Rep

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III–V semiconductors nanowires (NW) have recently attracted a significant interest for their potential application in the development of high efficiency, highly-integrated photonic devices and in particular for the possibility to integrate direct bandgap materials with silicon-based devices. Here we report the absorbance properties of GaAs-AlGaAs-GaAs core-shell-supershell NWs using photo-acoustic spectroscopy (PAS) measurements in the spectral range from 300 nm to 1100 nm wavelengths. The NWs were fabricated by self-catalyzed growth on Si substrates and their dimensions (length ~5 μm, diameter ~140–150 nm) allow for the coupling of the incident light to the guided modes in near-infrared (IR) part of the spectrum. This coupling results in resonant absorption peaks in the visible and near IR clearly evidenced by PAS. The analysis reveal broadening of the resonant absorption peaks arising from the NW size distribution and the interaction with other NWs. The results show that the PAS technique, directly providing scattering independent absorption spectra, is a very useful tool for the characterization and investigation of vertical NWs as well as for the design of NW ensembles for photonic applications, such as Si-integrated light sources, solar cells, and wavelength dependent photodetectors.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photo-acoustic spectroscopy revealing resonant absorption of self-assembled GaAs-based nanowires

Leahu

Petronijevic

Belardini

et al. 2017

Sci Rep

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“…The investigated self-catalyzed GaAs NWs were grown by solid-source molecular-beam epitaxy (MBE) on lithographyfree oxide patterns fabricated on p-Si(111) substrates by droplet epitaxy and spontaneous oxidation, as described in detail in Ref. [22]. The nucleation site density of the used template was 4.4 × 10 7 cm −2 .…”

Section: A Nanowire Growthmentioning

confidence: 99%

Te incorporation and activation as n -type dopant in self-catalyzed GaAs nanowires

Hakkarainen

Piton

Fiordaliso

et al. 2019

Phys. Rev. Materials

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Dopant atoms can be incorporated into nanowires either via the vapor-liquid-solid mechanism through the catalyst droplet or by the vapor-solid growth on the sidewalls. Si is a typical n-type dopant for GaAs, but in nanowires it often suffers from a strongly amphoteric nature in the vapor-liquid-solid process. This issue can be avoided by using Te, which is a promising but less common alternative for n-type doping of GaAs nanowires. Here, we present a detailed investigation of Te-doped self-catalyzed GaAs nanowires. We use several complementary experimental techniques, such as atom probe tomography, off-axis electron holography, micro-Raman spectroscopy, and single-nanowire transport characterization, to assess the Te concentration, the free-electron concentration, and the built-in potential in Te-doped GaAs nanowires. By combing the experimental results with a theoretical model, we show that Te atoms are mainly incorporated by the vapor-liquid-solid process through the Ga droplet, which leads to both axial and radial dopant gradients due to Te diffusion inside the nanowires and competition between axial elongation and radial growth of nanowires. Furthermore, by comparing the free-electron concentration from Raman spectroscopy and the Te-atom concentrations from atom probe tomography, we show that the activation of Te donor atoms is 100% at a doping level of 4 × 10 18 cm −3 , which is a significant result in terms of future device applications.

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“…This technique enables fabrication of highly uniform NW ensembles with tailorable NW density. [32] They were then exposed to a tilted flux of Au that resulted in nonuniform gold layers above the three sides and the tip of the NWs. The light that impinges on such structures under a proper oblique angle will be differently absorbed for circular polarizations of opposite handedness; this optical activity is usually indirectly measured as a difference in power transmitted/reflected by the chiral nanostructure-setup.…”

Section: Introductionmentioning

confidence: 99%

Evidence of Optical Circular Dichroism in GaAs‐Based Nanowires Partially Covered with Gold

Leahu

Petronijevic

Belardini

et al. 2017

Advanced Optical Materials

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thus paves the way for the important applications spreading from negative refraction, [1][2][3] chiral sensing [4,5] to production of optical field carrying out optical angular momentum for quantum information applications. [6] It has been shown that plasmonic nanostructures forming 1D [7] elements, 2D metasurfaces, [8][9][10] and 3D metamaterials [11] can exhibit linear chiral response due to their own, intrinsic chirality. Also semiconductor nanostructures can exhibit chiral features. [12][13][14][15][16] From the optical point of view, chiral structures possess the ability to rotate the plane of the polarization of electromagnetic waves (optical activity), and give rise to circular dichroism-i.e., the difference in the absorption of right-and lefthanded circular polarized light.Apart from 3D chiral objects, the possibility to obtain optical chirality, i.e., optical activity, with nonchiral elements was studied in the past, [17] but only recently reconsidered. [18,19] This phenomenon is obtained when the experimental configuration composed by both the nonchiral object and the optical incident field is nonsuperimposable on its mirror image. [20] This is called "extrinsic" chirality; in our previous works we have investigated this type of chirality in tilted golden nanowires by means of both linear (reflection and absorption) and nonlinear (second harmonic generation) measurements. [20][21][22][23] III-V semiconductor nanowires (NWs) have been widely investigated since they exhibit good waveguiding properties thus offering a light manipulation at nanoscale. Coupling of the incident light to the discrete leaky waveguide modes above the bandgap in NWs leads to increased resonant absorption, thus paving the way for important applications such as energy harvesting, spectral selectivity, lasing, spin angular momentum generation, etc. [24][25][26][27] Metallic NWs have also been investigated for plasmonic laser applications [28][29][30] and possibility of surface plasmon polaritons excitation. [31] One step further is the partial covering of such NWs with gold: this can induce, along with the proper experiment setup, the symmetry breaking which leads to chiral response.In this paper, for the first time to our knowledge, we report on a circular dichroism behavior from semiconductor hexagonal Semiconductor nanostructures hybridized with metals have been known to offer new opportunities in nonlinear optics, plasmonics, lasing, biosensors; among them GaAs-based nanowires (NWs) hybridized with gold can offer new functionalities, as chiral sensing and light manipulation, as well as circular polarization sources. This study investigates GaAs-AlGaAs-GaAs NWs fabricated by self-catalyzed growth on Si substrates, and partially covered with gold, thus inducing the symmetry breaking and a potential chiral response. Three different samples are investigated, each of them with a different morphology, as the length and the overall diameter ranging from 4.6 to 5.19 µm and from 138 up to 165 nm, respectively. The samples are first char...

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Lithography-free oxide patterns as templates for self-catalyzed growth of highly uniform GaAs nanowires on Si(111)

Cited by 33 publications

References 47 publications

Photo-acoustic spectroscopy revealing resonant absorption of self-assembled GaAs-based nanowires

Photo-acoustic spectroscopy revealing resonant absorption of self-assembled GaAs-based nanowires

Te incorporation and activation as n -type dopant in self-catalyzed GaAs nanowires

Evidence of Optical Circular Dichroism in GaAs‐Based Nanowires Partially Covered with Gold

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