The electrodeposition at room temperature of silicon and germanium nanowires from the airand water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P1,4) containing SiCl4 as Si source or GeCl4 as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germ...

The optical absorption in a nanowire heterostructure consisting of a crystalline silicon core surrounded by a conformal shell of amorphous silicon is studied. We show that they exhibit extremely high absorption of 95% at short wavelengths (λ < 550 nm) and a concomitant very low absorption of down to less than 2% at long wavelengths (λ > 780 nm). These results indicate that our nanowires do not ...

Surface roughening during plasma enhanced chemical vapor deposition of hydrogenated amorphous silicon on crystal silicon substrates" Physical Review B. The morphology of a series of thin films of hydrogenated amorphous silicon ͑a-Si:H͒ grown by plasma-enhanced chemical-vapor deposition ͑PECVD͒ is studied using scanning tunneling microscopy. The substrates were atomically flat, oxide-free, single-cr...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Tapani Alasaarela Name of the doctoral dissertation Atomic layer deposited titanium dioxide in optical waveguiding applications Publisher School of Electrical Engineering Unit Department of Microand Nanosciences Series Aalto University publication series DOCTORAL DISSERTATIONS 57/2011 Field of research Photonics Manuscript sub...

The density and molar heat capacity at constant pressure of silicon have been determined with use of molecular dynamics (MD) simulation. The interaction between silicon atoms was expressed by the Sttilinger-Weber potential and MD calculation was conducted on crystalline, liquid and amorphous states of silicon at temperatures between 100 and 3000 K. The density and heat capacity obtained are sho...

The following article appeared in "Nanoparticle deposition in hydrogenated amorphous silicon films during rf plasma deposition," D.

The deformation mechanisms of silicon {001} surfaces during nanoscratching were found to depend strongly on the loading conditions. Nanoscratches with increasing load were performed at 2 μm/s (low velocity) and 100 μm/s (high velocity). The load-penetration-distance curves acquired during the scratching process at low velocity suggests that two deformation regimes can be defined, an elasto-plas...

The present Letter reports on self-diffusion in amorphous silicon. Experiments were done on ^{29}Si/^{nat}Si heterostructures using neutron reflectometry and secondary ion mass spectrometry. The diffusivities follow the Arrhenius law in the temperature range between 550 and 700 °C with an activation energy of (4.4±0.3)  eV. In comparison with single crystalline silicon the diffusivities are tre...

In this paper we study electron dynamics and transport in models of amorphous silicon and amorphous silicon hydride. By integrating the time-dependent Kohn–Sham equation, we compute the time evolution of electron states near the gap, and study the spatial and spectral diffusion of these states due to lattice motion. We perform these calculations with a view to developing ab initio hopping trans...

Paper presents the comparative investigation of photoluminescence and Raman scattering spectra of pure amorphous silicon films and amorphous silicon films with different size Si nanocrystallites. Several PL bands in the IR spectral range with maxima at 0.90, 0.98, 1.14 and 1.36 eV have been revealed in studied samples. The 0.90–0.98 eV PL bands are attributed to the band tail luminescence in Si...