Enhancement in Efficiency and Stability of Oxide-Free Blue Emission from Porous Silicon by Surface Passivation

1998 ◽  
Vol 536 ◽  
Author(s):  
H. Mizuno ◽  
N. Koshida
Keyword(s):  
Porous Silicon ◽  
Surface Chemistry ◽  
Surface Passivation ◽  
Blue Emission ◽  
Hydrogen Gas ◽  
Surface Oxide ◽  
Visible Emission ◽  
Pl Spectra ◽  
Illumination Method

AbstractThe establishment of tuning techniques of visible emission from porous silicon (PS) is very important from both physical and technological viewpoints. As previously reported that the photoluminescence (PL) spectra of PS can continuously be controlled from red to blue simply by postanodization illumination method without any growth of the surface oxide. Details of this oxide-free blue emission have been studied in terms of the PL decay dynamics and surface chemistry. We report here that post-preparation exposure of PS to hydrogen gas is very useful for improvement in efficiency and stability of blue PL. Based on this technique, it has become possible to get blue electroluminescence even at low bias voltages.

Comparative Optical Studies of Chemically Synthesized Silicon Nanocrystals

1996 ◽  
Vol 452 ◽  
Author(s):  
Gildardo R. Delgado ◽  
Howard W.H. Lee ◽  
Susan M. Kauzlarich ◽  
Richard A. Bley
Keyword(s):  
Porous Silicon ◽  
Silicon Nanocrystals ◽  
Surface Passivation ◽  
Theoretical Calculations ◽  
Dominant Role ◽  
Blue Emission ◽  
Surface States ◽  
Si Nanocrystals ◽  
Optical And Electronic Properties ◽  
Passivation Layers

AbstractWe studied the optical and electronic properties of silicon nanocrystals derived from two distinct fabrication procedures. One technique uses a controlled chemical reaction. In the other case, silicon nanocrystals are produced by ultrasonic fracturing of porous silicon layers. We report on the photoluminescence, photoluminescence excitation, and absorption spectroscopy of various size distributions derived from these techniques. We compare the different optical properties of silicon nanocrystals made this way and contrast them with that observed in porous silicon. Our results emphasize the dominant role of surface states in these systems as manifested by the different surface passivation layers present in these different fabrication techniques. Experimental absorption measurements are compared to theoretical calculations with good agreement. Our results provide compelling evidence for quantum confinement in both types of Si nanocrystals. Our results also indicate that the blue emission from very small Si nanocrystals corresponds to the bandedge emission, while the red emission arises from traps.

Surface Engineered Porous Silicon-based Nanostructures for Cancer Therapy

2012 ◽  
Vol 1416 ◽  
Author(s):  
Adi Tzur-Balter ◽  
Naama Massad-Ivanir ◽  
Ester Segal
Keyword(s):  
Porous Silicon ◽  
Surface Chemistry ◽  
Electrochemical Etching ◽  
Release Kinetics ◽  
Drug Carrier ◽  
Drug Loading ◽  
Nitrogen Adsorption ◽  
Cancer Drug ◽  
Cytotoxicity Studies

ABSTRACTIn this work, nanostructured porous silicon (PSi) hosts, synthesized by electrochemical etching of Si, are designed to carry and release the anti cancer drug, mitoxantrone dihydrochloride (MTX). We study the effect of surface chemistry of the Si scaffold on its properties as a drug carrier. The freshly-etched PSi is modified by surface alkylation using thermal hydrosilylation with 1-dodecene. Fourier-transform infrared spectroscopy and nitrogen adsorption-desorption measurements are employed to characterize the PSi carriers after chemical modification. Both, drug loading efficiency and release kinetics are found to be significantly affected by surface chemistry of the PSi. In vitro cytotoxicity studies on human breast carcinoma (MDA-MB-231) cells show that the MTX released from the PSi hosts maintains its cytotoxic functionality.

Tuning the Pore Size and Surface Chemistry of Porous Silicon for Immunoassays

2000 ◽  
Vol 182 (1) ◽  
pp. 547-553 ◽  
Author(s):  
A.M. Tinsley-Bown ◽  
L.T. Canham ◽  
M. Hollings ◽  
M.H. Anderson ◽  
C.L. Reeves ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Surface Chemistry ◽  
Pore Size

Influence of the Surfaces Characteristics on the Luminescent Property of Porous Silicon

2014 ◽  
Vol 1052 ◽  
pp. 181-187
Author(s):  
Yan Li Ding ◽  
Yue Zhao ◽  
Yue Feng ◽  
Xiao Yan Liang ◽  
Lin Jun Wang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Porous Silicon ◽  
Luminescent Property ◽  
Blue Emission ◽  
Surface States ◽  
Green Emission ◽  
Decay Measurement ◽  
Photoconductivity Decay

Photoluminescence of porous silicon (PS) prepared by different etched time was studied. The photoluminescence might originate from the recombination of carriers and surface states, which was proved by FTIR, Raman spectroscopy and SEM. Furthermore, the hydrogen-related groups on the PS surface could eliminate the surface states for the blue emission, but the quantities of surface states for the green emission were depended on the uncovered area on the PS surface. Moreover, the shape of photoconductivity curve was depended on the quantities of the surface states, which also was related to the uncovered area on the PS surface. In addition, the results of the microwave-detected photoconductivity decay measurement indicated thatthe defects on the PS surface increased with the increase of the etched time, which would be related to the increase of the depth of pores.

Blue emission in porous silicon: Oxygen-related photoluminescence

1994 ◽  
Vol 49 (11) ◽  
pp. 7821-7824 ◽  
Author(s):  
L. Tsybeskov ◽  
Ju. V. Vandyshev ◽  
P. M. Fauchet
Keyword(s):  
Porous Silicon ◽  
Blue Emission ◽  
Silicon Oxygen

Blue emission of porous silicon intensified by boron deposition

2005 ◽  
Vol 40 (18) ◽  
pp. 5071-5073 ◽  
Author(s):  
Yue Zhao ◽  
Dongsheng Li ◽  
Deren Yang ◽  
Minghua Jiang
Keyword(s):  
Porous Silicon ◽  
Blue Emission
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