The realization of a pn-diode using only silicon nanoparticles

Meseth, Martin; Ziółkowski, Pawel; Schierning, Gabi; Theissmann, Ralf; Petermann, Nils; Wiggers, Hartmut; Benson, Niels; Schmechel, Roland

doi:10.1016/j.scriptamat.2012.04.039

Cited by 16 publications

(15 citation statements)

References 11 publications

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“…Energy dispersive X-ray scans across the structure in panel (e) confirm that the oxygen content in the porous region is enhanced by at least a factor of 4. 94 Correlating the SEM image in panel (e) to the thermal conductivity map in panel (b) suggests that the porous regions clearly visible in SEM exhibit a lower thermal conductivity compared to the surrounding area. At least in principle, this apparently lower thermal conductivity could arise from the local increase of the absorbed laser power, which in turn could be caused by the roughness of the surface visible in the SEM micrographs.…”

Section: B Bulk-nanocrystalline Siliconmentioning

confidence: 92%

Spatially resolved determination of thermal conductivity by Raman spectroscopy

Stoib¹,

Filser²,

Stötzel³

et al. 2014

Semicond. Sci. Technol.

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We review the Raman shift method as a non-destructive optical tool to investigate the thermal conductivity and demonstrate the possibility to map this quantity with a micrometer resolution by studying thin film and bulk materials for thermoelectric applications. In this method, a focused laser beam both thermally excites a sample and undergoes Raman scattering at the excitation spot. The temperature dependence of the phonon energies measured is used as a local thermometer. We discuss that the temperature measured is an effective one and describe how the thermal conductivity is deduced from single temperature measurements to full temperature maps, with the help of analytical or numerical treatments of heat diffusion. We validate the method and its analysis on 3-and 2-dimensional single crystalline samples before applying it to more complex Si-based materials. A suspended thin mesoporous film of phosphorus-doped laser-sintered Si 78 Ge 22 nanoparticles is investigated to extract the in-plane thermal conductivity from the effective temperatures, measured as a function of the distance to the heat sink. Using an iterative multigrid Gauss-Seidel algorithm the experimental data can be modelled yielding a thermal conductivity of 0.1 W/m K after normalizing by the porosity. As a second application we map the surface of a phosphorus-doped 3-dimensional bulknanocrystalline Si sample which exhibits anisotropic and oxygen-rich precipitates. Thermal conductivities as low as 11 W/m K are found in the regions of the precipitates, significantly lower than the 17 W/m K in the surrounding matrix. The present work serves as a basis to more routinely use the Raman shift method as a versatile tool for thermal conductivity investigations, both for samples with high and low thermal conductivity and in a variety of geometries.

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Section: B Bulk-nanocrystalline Siliconmentioning

confidence: 92%

Spatially resolved determination of thermal conductivity by Raman spectroscopy

Stoib¹,

Filser²,

Stötzel³

et al. 2014

Semicond. Sci. Technol.

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“…It turns out that negligible sintering is observed, consistent with Meseth et al's work. 13 However, the sintering of Si NCs becomes apparent when the hot-pressing temperature increases to 950 • C, as shown in Fig. 3(b).…”

Section: Methodsmentioning

confidence: 95%

“…It has been shown that viscous flow induced by the melting of oxide at the NC surface and that of smaller Si NCs in a Si-NC ensemble predominately determines the sintering process of Si NCs. 13 Although the exposure of Si NCs to air is minimized in the current work, oxide at the NC surface must have been formed somehow. Given the fact that P may even enhance the oxidation of Si NCs, 9 considerable oxide should exist at the surface of our P-hyperdoped Si NCs.…”

Section: Methodsmentioning

confidence: 97%

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Low-resistivity bulk silicon prepared by hot-pressing boron- and phosphorus-hyperdoped silicon nanocrystals

Luan

Koura

et al. 2014

AIP Advances

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Technologically important low-resistivity bulk Si has been usually produced by the traditional Czochralski growth method. We now explore a novel method to obtain low-resistivity bulk Si by hot-pressing B- and P-hyperdoped Si nanocrystals (NCs). In this work bulk Si with the resistivity as low as ∼ 0.8 (40) mΩ•cm has been produced by hot pressing P (B)-hyperdoped Si NCs. The dopant type is found to make a difference for the sintering of Si NCs during the hot pressing. Bulk Si hot-pressed from P-hyperdoped Si NCs is more compact than that hot-pressed from B-hyperdoped Si NCs when the hot-pressing temperature is the same. This leads to the fact that P is more effectively activated to produce free carriers than B in the hot-pressed bulk Si. Compared with the dopant concentration, the hot-pressing temperature more significantly affects the structural and electrical properties of hot-pressed bulk Si. With the increase of the hot-pressing temperature the density of hot-pressed bulk Si increases. The highest carrier concentration (lowest resistivity) of bulk Si hot-pressed from B- or P-hyperdoped Si NCs is obtained at the highest hot-pressing temperature of 1050 °C. The mobility of carriers in the hot-pressed bulk Si is low (≤ ∼ 30 cm-2V-1s-1) mainly due to the scattering of carriers induced by structural defects such as pores.

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“…This is the reason why this type of process is currently widely used in solar cell production. However, despite its potential application for nanostructure doping such as nano-grains in nc-Si [1,2,4], nanowires [5] or nanocrystals [6,7], atomic transport in nanometric phases is still poorly known. In the case of nc-Si, it has been shown that atomic transport kinetics could be enhanced in nanograins and that triple junction diffusion is several orders of magnitude faster than grain boundary (GB) diffusion [8,9].…”

mentioning

confidence: 99%

Anomalous B diffusion profiles in nanocrystalline Si

Portavoce

2015

Scripta Materialia

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The realization of a pn-diode using only silicon nanoparticles

Cited by 16 publications

References 11 publications

Spatially resolved determination of thermal conductivity by Raman spectroscopy

Spatially resolved determination of thermal conductivity by Raman spectroscopy

Low-resistivity bulk silicon prepared by hot-pressing boron- and phosphorus-hyperdoped silicon nanocrystals

Anomalous B diffusion profiles in nanocrystalline Si

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