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Experimental evidence of the photonic bandgap and defect effect in Si‐SiO 2 multilayer structures
Author(s) -
Bouaziz L.,
Nachi K.,
Gamra D.,
Lejeune M.,
Zeinert A.,
Zellama K.,
Bouchriha H.
Publication year - 2015
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201400171
Subject(s) - photonic crystal , band gap , materials science , reflection (computer programming) , optoelectronics , silicon , layer (electronics) , photonics , sputter deposition , transmission (telecommunications) , optics , spectral line , sputtering , thin film , nanotechnology , physics , telecommunications , astronomy , computer science , programming language
We have elaborated a one dimensional photonic crystal (Si/SiO 2 ) by depositing alternative silicon and silica layers by radiofrequency magnetron sputtering technique with cold plasma. After optimising the layer thickness to get good transmission, we studied the effect of the crystal layers number on the transmission and reflection spectra. We have shown that the photonic bandgap appears after five alternating Si and SiO 2 layers and is well structured after nine alternating layers with a pseudo‐band gap of 1.75 eV. We have also introduced a defect in the structure by changing the thickness of one Si layer, than of one SiO2 layer, in the middle of the structure and observed a corresponding defect mode frequency. Using a theoretical model based on the Plane Wave Expansion method and an appropriate code calculation, we have shown that to have a better defined photonic bandgap, the most appropriate number of periods of the alternating layers should be higher than ten and corresponds to a photonic bandgap of 1.60 eV. We have also theoretically reproduced the experimental transmission and reflection spectra with good agreement.