Modification of Visible Light Emission from Silicon Nanocrystals as a Function of Size, Electronic Structure, and Surface Passivation

1998 ◽  
Vol 536 ◽  
Author(s):  
M.V. Wolkin ◽  
J. Jorne ◽  
P.M. Fauchet ◽  
G. Allan ◽  
C. Delerue
Keyword(s):  
Porous Silicon ◽  
Silicon Nanocrystals ◽  
Surface Passivation ◽  
Light Emission ◽  
Electrochemical Etching ◽  
Theoretical Calculations ◽  
Surface Oxidation ◽  
Stain Etching ◽  
Visible Light Emission ◽  
Effect Of Surface

AbstractThe effect of surface passivation and crystallite size on the photoluminescence of porous silicon is reported. Oxygen-free porous silicon samples with medium to ultra high porosities have been prepared by using electrochemical etching followed by photoassisted stain etching. As long as the samples were hydrogen-passivated the PL could be tuned from the red (750nm) to the blue (400nm) by increasing the porosity. We show that when surface oxidation occurred, the photoluminescence was red-shifted. For sizes smaller than 2.8nm, the red shift can be as large as 1eV but for larger sizes no shift has been observed. Comparing the experimental results with theoretical calculations, we suggest that the decrease in PL energy upon exposure to oxygen is related to recombination involving an electron or an exciton trapped in Si=O double bonds. This result clarifies the recombination mechanisms in porous silicon.

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.

Influence of reaction parameters on the photoluminescence properties of free standing functionalized silicon nanocrystals

2010 ◽  
Vol 1260 ◽  
Author(s):  
Anoop Gupta ◽  
Hartmut Wiggers
Keyword(s):  
Optical Properties ◽  
Surface Functionalization ◽  
Silicon Nanocrystals ◽  
Organic Molecules ◽  
Surface Passivation ◽  
Light Emission ◽  
Emission Spectra ◽  
Surface Oxidation ◽  
Free Standing ◽  
The Stability

AbstractWhile silicon nanostructures acquire novel optical properties due to miniaturization, the stability of light emission is severely limited because of exciton trapping due to surface oxidation coming along with the formation of defects. Grafting of organic molecules on a hydrogen-terminated silicon surface via hydrosilylation provides a promising route to stabilize their surface against oxidation. In this communication, we report on the effect of surface passivation on the optical properties of freestanding silicon nanocrystals (Si-NCs). The surface functionalization of hydrogen-terminated Si-NCs with organic molecules was achieved via liquid phase hydrosilylation. We demonstrate that surface functionalization does not preserve the original emission of hydrogen-terminated Si-NCs. It is observed that the emission spectrum of green emitting hydrogen-terminated Si-NCs is red shifted after surface functionalization. We find that the direction of shift does not depend on the type of organic ligands and the reaction conditions, however, the amount of shift can be altered. The factors influencing the shift in the emission spectra of functionalized Si-NCs with respect to hydrogen-terminated samples are discussed.

scholarly journals Tailorable, visible light emission from silicon nanocrystals

1999 ◽  
Vol 74 (21) ◽  
pp. 3164-3166 ◽  
Author(s):  
J. P. Wilcoxon ◽  
G. A. Samara
Keyword(s):  
Visible Light ◽  
Silicon Nanocrystals ◽  
Light Emission ◽  
Visible Light Emission

Structural, Surface Morphological and Photoluminescence Properties of Nanostructured Porous Silicon Material for Optoelectronics Application

2012 ◽  
Vol 584 ◽  
pp. 290-294 ◽  
Author(s):  
Jeyaprakash Pandiarajan ◽  
Natarajan Jeyakumaran ◽  
Natarajan Prithivikumaran
Keyword(s):  
Porous Silicon ◽  
Current Density ◽  
Light Emission ◽  
Electrochemical Etching ◽  
Light Emitting Diode ◽  
Radiative Transition ◽  
Sem Images ◽  
Optoelectronic Application ◽  
Gap Opening ◽  
P Type

The promotion of silicon (Si) from being the key material for microelectronics to an interesting material for optoelectronic application is a consequence of the possibility to reduce its device dimensionally by a cheap and easy technique. In fact, electrochemical etching of Si under controlled conditions leads to the formation of nanocrystalline porous silicon (PS) where quantum confinement of photo excited carriers and surface species yield to a band gap opening and an increased radiative transition rate resulting in efficient light emission. In the present study, the nanostructured PS samples were prepared using anodic etching of p-type silicon. The effect of current density on structural and optical properties of PS, has been investigated. XRD studies confirm the presence of silicon nanocrystallites in the PS structure. By increasing the current density, the average estimated values of grain size are found to be decreased. SEM images indicate that the pores are surrounded by a thick columnar network of silicon walls. The observed PL spectra at room temperature for all the current densities confirm the formation of PS structures with nanocrystalline features. PL studies reveal that there is a prominent visible emission peak at 606 nm. The obtained variation of intensity in PL emission may be used for intensity varied light emitting diode applications. These studies confirm that the PS is a versatile material with potential for optoelectronics application.

Visible light emission from apnjunction of porous silicon and microcrystalline silicon carbide

1993 ◽  
Vol 63 (9) ◽  
pp. 1209-1210 ◽  
Author(s):  
Toshiro Futagi ◽  
Takahiro Matsumoto ◽  
Masakazu Katsuno ◽  
Yasumitsu Ohta ◽  
Hidenori Mimura ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Porous Silicon ◽  
Visible Light ◽  
Light Emission ◽  
Microcrystalline Silicon ◽  
Visible Light Emission

The Oxidation Behavior of Silicon Nanocrystals in the Submonolayer Region

1997 ◽  
Vol 486 ◽  
Author(s):  
J. Diener ◽  
M. Ben-Chorin ◽  
D. I. Kovalev ◽  
G. Polisski ◽  
F. Koch
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Porous Silicon ◽  
Silicon Nanocrystals ◽  
Oxidation Behavior ◽  
Surface Oxidation ◽  
Square Root ◽  
Mesoporous Silicon ◽  
Si Nanocrystals ◽  
Evolution Of Oxygen

AbstractFourier transform infrared spectroscopy is used to determine the time evolution of oxygen incorporation onto the surface of silicon nanocrystals. Oxygen concentrations up to one monolayer are investigated. The temporal progress of surface oxidation of Si nanocrystals in porous silicon shows a linear dependence on the square root of the oxidation time. This is similar to the oxidation of bulk Si and mesoporous silicon.

Bright visible light emission from electro-oxidized porous silicon

1993 ◽  
pp. 593-602
Author(s):  
J.C. Vial ◽  
S. Billat ◽  
A. Bsiesy ◽  
G. Fishman ◽  
F. Gaspard ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Visible Light ◽  
Light Emission ◽  
Oxidized Porous Silicon ◽  
Visible Light Emission

Visible light emission from innate silicon nanocrystals in an oxide matrix grown at low temperature

2006 ◽  
Vol 17 (8) ◽  
pp. 2073-2077 ◽  
Author(s):  
Z X Cao ◽  
R Song ◽  
L B Ma ◽  
Y Du ◽  
A L Ji ◽  
...  
Keyword(s):  
Low Temperature ◽  
Visible Light ◽  
Silicon Nanocrystals ◽  
Light Emission ◽  
Oxide Matrix ◽  
Visible Light Emission

Bright visible light emission from electro-oxidized porous silicon

1993 ◽  
Vol 185 (1-4) ◽  
pp. 593-602 ◽  
Author(s):  
J.C. Vial ◽  
S. Billat ◽  
A. Bsiesy ◽  
G. Fishman ◽  
F. Gaspard ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Visible Light ◽  
Light Emission ◽  
Oxidized Porous Silicon ◽  
Visible Light Emission
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