Optical and electronic properties of periodic Si nanostructures

Tavkhelidze, A.; Bayramov, Ayaz; Aliyeva, Yegana; Jangidze, Larissa; Skhiladze, Givi; Asadullayeva, S. G.; Alekperov, O. Z.; Mamedov, Nazim

doi:10.1002/pssc.201700093

Cited by 9 publications

(1 citation statement)

References 17 publications

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“…Carrier transport measurements, G-doped junction characteristics and measurements of optical characteristics [34,35] indicate that nanograting fabrication leads to reduction of density of quantum states in both 2D and 3D structures. In our opinion, this is owing to the special boundary conditions imposed by a nanograting on the electron wave function.…”

Section: Resultsmentioning

confidence: 98%

Nanograting layers of Si

et al. 2019

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The paper presents research regarding the complex behavior of materials based on Si and SiO2, geometrically processed at nano-scale. The geometry, which induces the doping effect (G-doping), occurred when it was possible to fabricate nanograting structures. Studies on the influence of nanograting structures on the properties of materials have shown that this process may lead to effects similar to those created by doping with donors. The resistivity values measured in Si-based nanograting layers, for example, were approximately 10−2 Ω cm, similar to those of Si semiconductors doped with phosphorus ‘impurities’ having a volume concentration of 1018 cm−3. This increase in electronic properties, as a result of the nanograting structure, seems to appear due to the fact that the electrons rejected in the process are placed in the structure vacancies. It has been experimentally proven that, in the case of semiconductors, the nanograting structuring makes the rejected electrons from the valence band to be placed in the conduction band. In the paper, after samples fabrication with nanograting structures on Si films placed on SiO2 support, the I–V curves of the obtained layers were drawn, both by measuring in four points and also in two points. The resistivity measurements were made in two directions: along and perpendicular to the strips of the structure and showed the existence of an anisotropy.

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Section: Resultsmentioning

confidence: 98%

Nanograting layers of Si

et al. 2019

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Negative Magnetoresistance in Si Nanograting Layers

Tavkhelidze

Grabecki

Jangidze

et al. 2019

Physica Status Solidi (a)

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Experimental measurements of low-temperature electron transport across Si nanogratings with 200 nm period are reported. The structure is fabricated of silicon on insulator layer using laser interference lithography followed by reactive ion etching. For transport measurements, macroscopic Hall bar formed in the patterned layer is used. The main result is negative magnetoresistance observed for temperatures lower than 60 K and not saturating in magnetic fields up to 9 Tesla. It is interpreted in terms of weak localization suppression and fit the magnetoresistance curves by both the two-dimensional and three-dimensional theoretical models. Surprisingly, both models describe satisfactorily the data and thus the problem of dimensionality remains unsettled. However, obtained values of the phase coherence lengths are significantly smaller than both the nanograting period and layer thickness, indicating that the dominant scattering mechanism is not result of the nanostructure geometry.

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Spectroscopic planar diffraction ellipsometry of Si‐based multilayer structure with subwavelength grating

Mamedov

Tavkhelidze

Bayramov

et al. 2017

Phys. Status Solidi C

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Spectroscopic ellipsometry has been applied at room temperature to a multilayer device structure with plain and nanograting‐embedded Si layer on the top. In both cases, the real and imaginary parts of the complex dielectric function of the top layer have been retrieved. In nanograting case, ellipsometric data were collected in planar diffraction geometry. A profound change in dielectric function in the photon energy region between 1.5 and 3.5 eV is established for nanograting‐embedded Si layer compared to plain Si layer. Both real and imaginary parts of the former are no longer Si‐like and resemble more those for metals. The maximum of interband density‐of‐states for optical transitions is positioned at 2.1 eV and coincides with the energy of optical transitions from the main irradiative eigenstate. The obtained results are discussed in terms of geometry‐induced doping changes in interband density of states.

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Optical and electronic properties of periodic Si nanostructures

Cited by 9 publications

References 17 publications

Nanograting layers of Si

Nanograting layers of Si

Negative Magnetoresistance in Si Nanograting Layers

Spectroscopic planar diffraction ellipsometry of Si‐based multilayer structure with subwavelength grating

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