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Journal or Publication Title:
Armenian Journal of Physics=Ֆիզիկայի հայկական հանդես
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Title:
NANOSCALE POROUS SILICON PHOTONIC MICROCAVITY STRUCTURES FOR OPTICAL SENSING OF ETHANOL
Creator:
P. N. Patel ; V. Mishra ; A. K. Panchal ; J. D'Cruz
Subject:
Physics ; Optics ; Materials science
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Abstract:
Porous silicon (PS) is emerged as a unique and promising nanomaterial for the optoelectronic devices and the sensing applications. In this study, nanoscale PS photonic microcavity (MC) sensor device structures, prepared by anodization of crystalline silicon wafer, are proposed as a large surface area matrix for sensing the different concentrations of ethanol solution. Fabry–Perot reflectance fringes were observed from the PSMC structures prepared under the anodization conditions with different current densities and etching time profiles. The optical characterization of the PSMC structures, before thermal oxidation, showed a sharp photonic resonance and blue shifted and narrowed after thermal oxidation process. The photonic resonance wavelength of PSMC sensor device showed significant red shift after capillary adsorption of ethanol because the structure refractive index changes after infiltration of the pores of the PSMC sensor device structures. The resonance wavelength shift showed a linear relationship with the different concentrations of ethanol for the natural oxidized PSMC structures and thermal oxidized PSMC structures. The thermal oxidized structures showed better sensibility feature and this result was attributed to passivation of the surface devices. Also, we observe the ability of reversible sensing by PSMC sensor device structures.