Journal of the Korean Physical Society

pISSN 0374-4884 eISSN 1976-8524


J. Korean Phy. Soc. 2009; 55(1): 288-293

Published online July 15, 2009

Copyright © The Korean Physical Society.

Smart-particles-containing Multiple Photonic Band Gaps Based onRugate-structured Porous Silicon

Sungjin Kim, Cheolyoung Park, SungGi Lee, Honglae Sohn, YoungChun Ko


Photonic crystals (PCs) containing multi-encoded rugate poroussilicon (PSi) were prepared by applying a composite waveform, a sumof three computer-generated pseudo-sinusoidal current waveforms. ThePCs displayed three sharp photonic band gaps in the opticalreflectivity spectrum. Three types of rugate PSi (H-, HO-, andR-terminated rugate PSi) were used in this study. Free-standingrugate PSi films were obtained from the silicon substrate byapplying an electropolishing current and were then made intoparticles by using an ultrasono-method in an ethanol solution.Sensing experiments using these particles with organic solvents suchas methanol and hexane were performed. Condensation of the organicvapors in the pores increased the refractive index of all theparticles and resulted in a red shift in the photonic peaks. Thespecificity of adsorption or capillary condensation at the surfacesof the smart particles depended dramatically on the surfacechemistry.

Keywords: Rugate porous silicon, Sensor, Organic vapors, Optical encoding