Free-standing porous silicon film with a tunable microcavity containing nematic liquid crystal

2008 ◽  
Author(s):  
G.V. Tkachenko ◽  
A.A. Dyomin ◽  
V. Tkachenko ◽  
G. Abbate ◽  
L. De Stefano ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Porous Silicon ◽  
Nematic Liquid Crystal ◽  
Silicon Film ◽  
Free Standing

Tunable NIR filter based on a free-standing porous silicon film containing nematic liquid crystal

2009 ◽  
Vol 11 (10) ◽  
pp. 105106 ◽  
Author(s):  
Georgiy V Tkachenko ◽  
Volodymyr Tkachenko ◽  
Luca De Stefano ◽  
Igor A Sukhoivanov
Keyword(s):  
Liquid Crystal ◽  
Porous Silicon ◽  
Nematic Liquid Crystal ◽  
Silicon Film ◽  
Free Standing

Photoluminescence of Liquid Crystal Infiltrated Porous Silicon Film

2010 ◽  
Vol 663-665 ◽  
pp. 812-815 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Liquid Crystal ◽  
Porous Silicon ◽  
Nematic Liquid Crystal ◽  
Silicon Film ◽  
Luminescent Properties ◽  
Silicon Films ◽  
The Other ◽  
Deep Blue ◽  
Pl Spectrum ◽  
The Cost

We have investigated the photoluminescence (PL) of a porous silicon film in which a typical nematic liquid crystal 4-pentyl-4’-cyanobiphenyl infiltrated. Before the liquid crystal filtration, the PL spectrum of the porous silicon film is comprised of two luminescent bands, one of which is located at about 600 nm whereas the other of which is located at about 450 nm. After the liquid crystal filtration, the porous silicon film gives off intense deep-blue PL with its peak located at about 400 nm at the cost of the complete quenching of the PL from the original porous silicon film. Our results have demonstrated that the luminescent properties of porous silicon films can be dramatically modified by liquid crystal infiltration.

Polarizing Optical Microscopic Characterization of Nematic Liquid Crystal Confined in Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 83-87
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Experimental Study ◽  
Liquid Crystal ◽  
Porous Silicon ◽  
Optical Microscopy ◽  
Nematic Liquid Crystal ◽  
Experimental Investigations ◽  
Electro Optic ◽  
The Given

With polarizing optical microscopy we have investigated the electro-optic properties of a nematic liquid crystal 4-n-pentyl-4′-cyanobipheny confined in the microchannels of porous silicon. Experimental study shows clearly that the liquid crystal molecules tend to align parallel to the direction of the pore columns in porous silicon. Schlieren textures with S = +1 and +2 disclinations were recorded. Our experimental investigations show that uniaxial alignment, the planar radial and the escaped radial configurations exist around the given microchannels of porous silicon.

Photonic Polymer Replicas from Distributed Bragg Reflectors Structured Porous Silicon

2007 ◽  
Vol 7 (11) ◽  
pp. 4165-4168
Author(s):  
Jihoon Kim ◽  
Youngdae Koh ◽  
Seunghyun Jang ◽  
Young Chun Ko ◽  
Hee-Gweon Woo ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Silicon Film ◽  
Composite Films ◽  
Nanometer Scale ◽  
Crystal Layer ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Free Standing ◽  
Reflectivity Spectrum ◽  
Silicon Photonic

Well defined 1-dimentional (1-D) photonic crystals of polymer replicas have been successfully obtained. DBR porous silicon containing nanometer-scale pores are prepared by an anodic electrochemical etch of p++-type silicon wafer. The resulting DBR porous silicon film removed from the substrate by applying an electropolishing current has been thermally oxidized in the furnace at 400 °C for 3 h. Oxidized DBR PSi/polystyrene composite films are prepared by casting of polymer solution onto a free-standing porous silicon photonic crystal layer. Flexible photonic polymer replicas have been prepared after the removal of oxidized DBR PSi matrix in HF/H2O mixture solution. Polymer replicas exhibit a sharp resonance in the reflectivity spectrum. Optical characteristics of photonic polymer replica indicate that the surface of polymer film has a negative structure of DBR PSi. This replica is stable in aqueous solutions for several days without any degradation.

Photonic Polymer Replicas from Distributed Bragg Reflectors Structured Porous Silicon

2007 ◽  
Vol 7 (11) ◽  
pp. 4165-4168 ◽  
Author(s):  
Jihoon Kim ◽  
Youngdae Koh ◽  
Seunghyun Jang ◽  
Young Chun Ko ◽  
Hee-Gweon Woo ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Silicon Film ◽  
Composite Films ◽  
Nanometer Scale ◽  
Crystal Layer ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Free Standing ◽  
Reflectivity Spectrum ◽  
Silicon Photonic

Well defined 1-dimentional (1-D) photonic crystals of polymer replicas have been successfully obtained. DBR porous silicon containing nanometer-scale pores are prepared by an anodic electrochemical etch of p++-type silicon wafer. The resulting DBR porous silicon film removed from the substrate by applying an electropolishing current has been thermally oxidized in the furnace at 400 °C for 3 h. Oxidized DBR PSi/polystyrene composite films are prepared by casting of polymer solution onto a free-standing porous silicon photonic crystal layer. Flexible photonic polymer replicas have been prepared after the removal of oxidized DBR PSi matrix in HF/H2O mixture solution. Polymer replicas exhibit a sharp resonance in the reflectivity spectrum. Optical characteristics of photonic polymer replica indicate that the surface of polymer film has a negative structure of DBR PSi. This replica is stable in aqueous solutions for several days without any degradation.

Active NIR filter with a free-standing porous silicon microcavity containing liquid crystal

2008 ◽  
Author(s):  
Georgiy V. Tkachenko ◽  
Volodymyr Tkachenko ◽  
Giancarlo Abbate ◽  
Luca De Stefano ◽  
Igor A. Sukhoivanov
Keyword(s):  
Liquid Crystal ◽  
Porous Silicon ◽  
Free Standing
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