Desarrollo de filtros interferenciales para emisores fotoluminiscentes basados en silicio poroso

Abstract

Las propiedades fotoluminiscentes y electroluminiscentes en el visible del silicio poroso hacen de éste un material muy interesante para el desarrollo de disposotivos optoelectrónicos. Para la obtención de dispositivos de calidad es necesario reducir la semianchura del espectro de luminiscencia del silicio poroso, típicamente de unos 100 nm, para conseguir una emisión monocromática. Esto puede conseguirse formando sobre la capa luminiscente una estructura multicapa, también de silicio poroso, que actúe a modo de filtro interferencial. Así se consigue estrechar el rango de emisión cuanto se desee, sencillamente diseñando el filtro de manera conveniente. En este artículo se estudian las propiedades ópticas de las capas de silicio poroso para el posterior diseño de estos filtros. Palabras clave: silicio poroso, multicapa, filtro interferencial, dispositivos optoelectrónicos, propiedades ópticas Development of interference filters for porous silicon based photoluminescent devicesPorous silicon's photoluminescent and electroluminescent properties make it a very interesting material for the development of optoelectronic devices. To obtain high quality devices it is mandatory to narrowen the porous silicon luminescent spectrum, tipically about 100 nm wide. This can be obtained by forming a porous silicon multilayer structure on the luminescent layer that acts as an interference filter. Thus, the emission spectrum can be narrowed as much as wished by simply designing the filter in the appropriate way. In this article, the optical properties of porous silicon layers are studied for future filter design.

Time-Resolved Spectroscopy of Ethanol Evaporation on Free-Standing Porous Silicon Photonic Microcavities

“…The porosity and the thickness for each monolayer of Psi are measured using gravimetric methods. To get the refractive index of each Psi monolayer, we used the effective medium theory of Bruggeman, while considering that we have a homogeneous medium that is associated with an effective dielectric function [ 20 ]. This effective dielectric function is related to the dielectric functions of the two mediums forming this material (air and silicon), where it is assumed that all of the pores or islands of the bulk material experience an average electric field [ 21 ]; the equation is expressed as follows: where is the volume fraction of air within the Psi layer (porosity); is the dielectric function of air; is the dielectric function of c-Si, and represents the dielectric function of Psi; and, is the volume fraction of c-Si in the porous layer.…”

Time-Resolved Spectroscopy of Ethanol Evaporation on Free-Standing Porous Silicon Photonic Microcavities

“…The porosity and the thickness for each monolayer of Psi are measured using gravimetric methods. To get the refractive index of each Psi monolayer, we used the effective medium theory of Bruggeman, while considering that we have a homogeneous medium that is associated with an effective dielectric function [20]. This effective dielectric function is related to the dielectric functions of the two mediums forming this material (air and silicon), where it is assumed that all of the pores or islands of the bulk material experience an average electric field [21]; the equation is expressed as follows:…”

UV distributed Bragg reflectors build from porous silicon multilayers

“…It can thus be assumed that the oxidized PS structure is composed by three components: crystalline silicon, silicon oxide and air [31]. The refractive index (n pso ) of the oxidized PS-ML was calculated using a model that considers the three media [15]. The equation that supports that model is as follows (Eq.…”

“…Both oxidation steps were conducted at atmospheric pressure. The RI of air, silicon and silicon oxide were calculated to predict the maxima of the re-flectance peak in the UV region [15]. It is suggested that the fabricated UV-DBR would be a suitable candidates for applications in short-wavelength devices since the formed structures are nano-sized PS with wide band-gap [16,17].…”