Investigation of Relationship between Reflection Resonance and Applied Current Density in Bragg Photonic Crystal

Distributed Bragg reflector porous silicon of different characteristics were formed to determine their optical constants in the visible wavelength range using a periodic square wave current between low and high current densities. The surface and cross-sectional SEM images of distributed Bragg reflector porous silicon were obtained using a cold field emission scanning electron microscope. The surface image of distributed Bragg reflector porous silicon indicates that the distributions of pores are even. The cross-sectional image illustrates that the multilayer of distributed Bragg reflector porous silicon exhibits a depth of few microns and applying of square current density during the etching process results two distinct refractive indices in the contrast. Distributed Bragg reflector porous silicon exhibited a porosity depth profile that related directly to the current-time profile used in etch. Its free-standing film was obtained by applying an electropolishing current.

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Free-Standing DBR Porous Silicon Film

Um¹,

Sohn²

2014

“…DBR PSi resulted in two discrete indices and displayed photonic structure of Bragg filters. Chemical modification of PSi multilayer exhibited the modification of its physical, chemical, and electronic properties [25,26] .…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Optically Encoded Porous Silicon Smart Particles

Sohn¹

2014

Optically encoded porous silicon smart particles were successfully fabricated from the free-standing porous silicon thin films using ultrasono-method. DBR PSi was prepared by an electrochemical etch of heavily doped p ++ -type silicon wafer. DBR PSi was prepared by using a periodic pseudo-square wave current. The surface-modified DBR PSi was prepared by either thermal oxidation or thermal hydrosilylation. Free-standing DBR PSi films were generated by lift-off from the silicon wafer substrate using an electropolishing current. Free-standing DBR PSi films were ultrasonicated to create DBRstructured porous smart particles. Optical characteristics of porous smart particles were measured by FT-IR spectroscopy. The surface morphology of porous smart particles was determined by FE-SEM.

“…Porous silicon has advantages for building optical structures as well as very high surface area with various surface chemistry and unusual optical properties. The porosity and pore size of porous silicon can be controlled by modulating the applied current densities [16][17][18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Porous Polymethylmethacrylate Film Showing Optical Reflectivity

Kim¹

2013

This paper describes a method for the preparation of porous polymethylmethacrylate showing optical reflectivity from the porous silicon template. A porous polymethylmethacrylate showing optical reflectivity was prepared by replicating porous silicon template which was obtained by applying a computer-generated periodic square current density and resulted in a mirror with high reflectivity in a specific narrow spectral region. A porous polymethylmethacrylate showing an excellent reflectivity was successfully obtained by dissolving the Porous silicon template from the porous polymethylmethacrylate composite film. A porous polymethylmethacrylate exhibited a sharp reflection resonance in the reflectivity spectrum. Surface image of the porous polymethylmethacrylate indicated that the surface of the porous polymethylmethacrylate film had a porous structure. These porous polymethylmethacrylate films in aqueous solutions were stable for several days without any degradation.