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Silicon Films (silicon + film)

Distribution by Scientific Domains

Physics and Astronomy	70%
Polymers and Materials Science	20%

Selected Abstracts

Photoluminescence-Based Sensing With Porous Silicon Films, Microparticles, and Nanoparticles

ADVANCED FUNCTIONAL MATERIALS, Issue 20 2009
Michael J. Sailor
Abstract Here, chemical sensors made from porous Si are reviewed, with an emphasis on systems that harness photoluminescence and related energy- and charge-transfer mechanisms available to porous Si-derived nanocrystallites. Quenching of luminescence by molecular adsorbates involves the harvesting of energy from a delocalized nanostructure that can be much larger than the molecule being sensed, providing a means to amplify the sensory event. The interaction of chemical species on the surface of porous Si can exert a pronounced influence on this process, and examples of some of the key chemical reactions that modify either the surface or the bulk properties of porous Si are presented. Sensors based on micron-scale and smaller porous Si particles are also discussed. Miniaturization to this size regime enables new applications, including imaging of cancerous tissues, indirect detection of reactive oxygen species (ROS), and controlled drug release. Examples of environmental and in vivo sensing systems enabled by porous Si are provided. [source]

Quantized Double-Layer Charging of Iron Oxide Nanoparticles on a-Si:H Controlled by Charged Defects in a-Si:H

ELECTROANALYSIS, Issue 12 2007
Martin Weis
Abstract Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film (a-Si:H) is reported. Quantized double-layer charging of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the excess of negative/positive charged defect states in the a-Si:H layer. The particular charge states in a-Si:H are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. [source]

Monte Carlo study of 2D electron gas transport including Pauli exclusion principle in highly doped silicon

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2008
F. Carosella
Abstract A Multi Sub-band Monte Carlo Simulator improved to efficiently include the Pauli Exclusion Principle is presented. It is used to study the transport in highly doped and ultra-thin silicon film. Both steady state and transient regime of transport for silicon films under uniform driving field are investigated. Such approach aims to be carried out in a full device simulator to improve the modeling of the access region of nano-Double Gate MOSFETs. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Characterization of strength properties of thin polycrystalline silicon films for MEMS applications

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1 2007
R. Boroch
ABSTRACT The aim of this work is to characterize the strength properties of polycrystalline silicon (polysilicon) with the use of tensile and bending test specimens. The strength of thin polysilicon films with different geometry, size and stress concentrations has been measured and correlated with the effective size of the specimen and its stress distribution. The test results are evaluated using a probabilistic strength approach based on the weakest link theory with the use of STAU software. The use of statistic methods of strength prediction of polysilicon test structures with a complex geometry and loading based on test values for standard material tests specimen has been evaluated. [source]

Effect of ion energy on structural and electrical properties of intrinsic microcrystalline silicon layer deposited in a matrix distributed electron cyclotron resonance plasma reactor

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2010
Sanjay K. Ram
Abstract Microcrystalline silicon films were deposited in a matrix distributed electron cyclotron resonance (MDECR) plasma enhanced chemical vapor deposition (PECVD) system using pure silane, under varying substrate bias conditions. Microstructural characterization of the films shows a lower void fraction and a preponderance of nanograins in films deposited at negative bias, while in positive bias a thin incubation layer is seen with a higher void fraction. Plasma emission studies reveal higher electron temperature and more atomic H at positive bias, which lead to early onset of crystallization. The microstructural properties of the films are correlated with the dark and phototransport properties. Our study demonstrates the importance of substrate bias in controlling the ion energy and properties of films deposited in the MDECR reactor. [source]

Cross-sectional AFM study of etching kinetics of oxidized porous silicon

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2004
J. C. Poler
Abstract We have studied the morphology and etching kinetics of partially oxidized porous silicon films. Film morphology and thickness was measured using cross-sectional atomic force microscopy. Air and UV-ozone oxidized porous silicon films were etched in buffered hydrofluoric acid. The observed etching rate was much faster than expected for a bulk film. These data consist of: direct visualization of cluster formation, enhanced etching rates and subsequent analysis of the liberated nanoparticles, and consistent with a mesoporous morphology of undulating Si nanowires. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polycrystalline silicon thin films on glass obtained by nickel-induced crystallization of amorphous silicon

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
J. A. Schmidt
Abstract In this work, we use the nickel-induced crystallization process to crystallize a-Si:H thin films at temperatures compatible with the utilization of glass substrates. Hydrogenated amorphous silicon films are deposited on planar float glass (Schott AF37) by plasma-enhanced chemical vapour deposition. The films, between 400 and 1400 nm thick, are grown intrinsic, slightly p-doped (p - ) or with a combined structure of heavily p-doped / slightly p-doped (p+/p - ) layers. On these films we sputter nickel with concentrations between 2.5×1014 and 3×1015 at./cm2, and then we anneal the samples in a standard nitrogen-purged tube furnace. The process evolves through the formation of the nickel silicide NiSi2, which has a lattice constant very similar to that of c-Si and acts as a nucleation centre. As a result of this thermal treatment we obtain thin polycrystalline films with a grain size over 100 ,m. The high crystallinity of the samples is confirmed through optical and electron microscopy observations, X-rays diffraction and Raman spectroscopy. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Dependence of transport properties in tunnel junction on boron doping

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010
M. J. Shi
Abstract Boron-doped hydrogenated silicon films with different gaseous doping ratio (B2H6/SiH4) were fabricated as recombination p layers in tunnel junctions. The measurements of I-V characteristics of the junctions and transparency spectra of p layer indicated that the best gaseous doping ratio of the recombination layer is 0.04, which is correlated to the degradation of short range order (SRO) in the inserted p thin film. The junction with such recombination layer has small resistance, near ohmic contact. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Determination of critical points on silicon nanofilms: surface and quantum confinement effects

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2008
Emmanouil Lioudakis
Abstract In this work, we present a comprehensive study of the optical properties of nanocrystalline silicon films with thickness varied from 5 to 30 nm. Spectroscopic ellipsometry is employed to determine the dielectric functions of these films using a structural two-layer model based on the rigorous Airy formula. Our investigation gives an important insight of the origin of critical points for direct and indirect gaps of nanocrystalline silicon films as well as the evolution of them with decreasing the film thickness. The influence of the quantum confinement effect due to the nanoscale grain size and the surface vibrations at the interface on the optical properties are examined in detail. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]