Thermal management and optical entrapment in multilayered porous silicon for use as waveguide (original) (raw)
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Porous silicon as a promising material for photonics
International Journal of Nanotechnology, 2011
Electrochemical etching-a usual technique in nanotechnology-creates porous silicon with novel and useful properties. The considerable and controllable changes in the electronic structure and refractive index of porous silicon make it a promising material for photonics in comparison with bulk silicon. In this paper, we review as well as report on some interesting and unique properties of porous silicon material. In studying porous silicon as a low-dimensional material, we focus on the effect of the surface passivation of silicon nanocrystals on photoluminescence characteristics of such zero-dimensional crystals. As an optical material, we demonstrate the fabrication method and optical properties of the planar waveguide as well as the active waveguide and optical interference filters operated in infrared wavelengths. In addition, we investigated the effect of energy transfer from silicon nanocrystals to erbium ions in the erbium-doped porous silicon waveguide and also elaborate on the origins of the difference between the reflectivity spectra from fabricated filters and that of the simulation program.
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Proceedings of …, 2000
Porous silicon (PS) has been known for quite a long time for its photoluminescence and for its usage as a sensing element. However, only in recent years this material has been proposed as a substrate for integrated optoelectronic devices and, despite the low fabrication costs ...
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ROMOPTO 2000: Sixth Conference on Optics, 2001
This work has been a team effort. The successful completion of this thesis was made possible through the generous support of Dr. Karl D. Hirschman, who not only provided the necessary vision and direction but also continuously gave encouragement and moral support. I would also like to thank Mr. Kevin Witt project sponsor through Semitool Inc. without which the project would have never gone forward. I also would like to express my gratitude to Joshua D. Winans; he was literally the backbone of the entire project by not only providing valuable ideas but also providing SEM images which are a very integral part of this thesis. Furthermore, I would like to thank my colleagues Shaoting Hu, Daiji Kawamura, Andrew McCabe and Chris Shea for their contributions and support. I would like to thank especially Patricia Meller for providing process support whenever needed. The completion of this project would not be possible without the generous support of the Semiconductor and Microsystems Fabrication Laboratory (SMFL) staff: Sean
Application to optical components of dielectric porous silicon multilayers
Applied Physics Letters, 1995
Narrow-band color filters have been integrated on porous silicon layers. Distributed Bragg reflectors and Fabry-Pérot interference filters based on layered porous silicon samples are demonstrated. The effects of narrowing and tuning the porous silicon emission band are shown in structures composed by Fabry-Pérot filters integrated on top of thick porous silicon layers.
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Porous silicon (PS) apart from its diverse properties from bulk Si is also identified to be a photonic material. PS single and multilayer samples are prepared on a polished surface of (1 0 0) Si substrate. A peak fitting technique has been discussed for XRD analysis in the case of a dichromatic beam. Theoretical simulations of light transmission for some special structures are also presented.
Progress in the field of integrated optoelectronics based on porous silicon
Thin Solid Films, 1997
Aluminum-porous silicon (Al-PS) Schottky junctions have demonstrated to be promising candidates for stable, wide band emission, silicon based light sources. Aluminum top contacts are defined by transforming the Al layer between different pads into anodic alumina (Al 2 O 3).The light emitted by the devices arises from the border of the metallic contact through the transparent and insulating alumina. With the aim of obtaining a higher external efficiency, different shapes for the aluminum top contact have been designed and characterised. The layout of the masks used in photolithography has been designed having in mind two possible applications for the light source: (1) as a silicon technologycompatible light source to be used for optical interconnections within VLSI-IC, and (2) as a pixel for 1D and 2D electroluminescent panels. An increase of external quantum efficiency due to increase of perimeter/area ratio has been demonstrated. Furthermore, the detection of the light emitted from the junction by means of a porous silicon photodetector integrated on the same chip is presented. Fabricated devices are characterised by means of electrical and optoelectronic techniques. q Elsevier Science S.A.
Nanostructure and optical propertes of porous silicon layer
Maǧallaẗ ǧāmiʻaẗ kirkūk, 2015
In this paper nanostructures Porous silicon layers have been prepared by electrochemical etching (ECE) technique of (111) P-type silicon wafer with a solution Electrolytic HF: ethanol at a concentration of 1:2 with various anodization currents and etching time of 20 min. The morphological, structural and optical properties of nanostructure porous silicon were investigated by Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD) and Photoluminescence (PL) respectively. From AFM images, we found that the PS layer has sponge like structure, and average diameter of pore and thickness of PS layer increased with increasing of the anodization currents. X-ray diffraction show that the crystal size was reduced toward nanometric scale, and then a broadening of diffraction peaks (111) was observed. The band gap of the samples was measured through the photoluminescence (PL) peak.
Recent progress in integrated waveguides based on oxidized porous silicon
Optical Materials, 2005
In this work we report the latest improvements in integrated optical waveguides based on oxidized porous silicon. Remarkably low propagation loss of 0.2 dB/cm in the visible is demonstrated. Straight waveguides of 1-10 cm long were fabricated in N +-type silicon substrates. Thickness of core region of all fabricated waveguides was of 8 lm while thickness of cladding layer was of 0.8, 1.5, and 2.5 lm. Optical loss in the visible and IR were measured by original method utilizing the 90°vertical bending at the waveguides endings which is a unique property of our waveguides. Significant improvement of the waveguide characteristics was obtained by optimizing the technological process: (a) eliminating the negative effect of swirl defects on uniformity of porous silicon layers; (b) developing the anodization regimes allowing the careful control of the porosity through the porous silicon thickness; (c) using silica mask instead of silicon nitride mask.
Journal of Molecular Structure
Silicon-on insulator (SO1) wafers, consisting of 33 micron thick p-type silicon epitaxial layer grown on 280 micron thick n-type (111) silicon substrate, were electrochemically etched in hydrofluoric acid (HF) to produce porous silicon (PS) samples. The pores of different size and different depth were obtained by etching at different time duration, from 10 to 80 min, using the constant concentration of 48% HF in ethanol solution. The structural and optical properties of porous layers were investigated by Raman, FTIR and photoluminescence (PL) spectroscopy, and scanning electron microscopy. SEM images showed high density of micrometer-sized pores whose morphology and density depended on the etching duration. For all samples the observed PL peak is in the visible spectral range. The intensity of the PL peak was increased with the etching zime. the exception was the epitaxial layer of the sampled etched for 80 min. It showed the strong decrease in the PL peak intensity. For thiw sample...
Porous silicon optical devices for sensing applications
Optical Materials, 2005
Porous silicon (PS) has a great potential in a wide range of fields due to its tuneable effective refractive index, which can be tailored through the precise control of the formation parameters. In particular, high/low porosity layer stacks result in optical multilayer interference filters, such as Bragg reflectors and optical microcavities. In addition, due to its large internal surface, the optical properties of porous silicon are highly sensitive to the environmental conditions. Hence, a change in these conditions results in a shift of the optical spectrum of the PS multilayer structures. In the present work, the optical behavior of PS mirrors is studied, revealing good performance in the visible wavelength range, and showing a great sensitivity to different liquids infiltrated into the porous structure. Furthermore, optical microcavities are also demonstrated to filter the photoluminescence emission of porous silicon, narrowing its spectral width and resulting in highly chromatical light emitting devices. These devices, along with the immobilization of biomolecules on the PS surface, will allow the development of low cost, high sensitivity optical biosensors.