The Origin Of Light Emission From Porous Silicon

1997 ◽  
Vol 486 ◽  
Author(s):  
M. Ben-Chorin ◽  
H. Heckler ◽  
D. Kovalev ◽  
B. Averboukh ◽  
G. Polisski ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Radiative Recombination ◽  
Light Emission ◽  
Hole Burning ◽  
Si Nanocrystals ◽  
Quantum Confined ◽  
Viable Model

AbstractWe report on luminescence hole burning experiments, which prove that radiative recombination between quantum confined states is the only viable model for the mechanism of the light emission from porous silicon. We find that more than 90% of the luminescence originates from quantum confined states inside the Si nanocrystals.

Theory of the Physical Properties of Si Nanocrystals

1994 ◽  
Vol 358 ◽  
Author(s):  
M. Lannoo ◽  
C. Delerue ◽  
G. Allan ◽  
E. Martin
Keyword(s):  
Porous Silicon ◽  
Radiative Recombination ◽  
Surface Defects ◽  
Stokes Shift ◽  
Optical Excitation ◽  
Recombination Time ◽  
Si Nanocrystals ◽  
Donor And Acceptor ◽  
Electron Hole Pair ◽  
Level Of Understanding

ABSTRACTThis paper reviews calculations concerning several aspects of silicon crystallites and their relevance for porous silicon. This begins with the optical properties of perfect crystallites: gap versus size, radiative recombination time, relative importance of phonon assisted transitions. A second part is devoted to the determination of the excitonic exchange splitting and of the Stokes shift which are found to bring a similar contribution (∼10 to 20 meV). The effect of surface defects like dangling bonds is then investigated with their contribution to the recombination time. The Auger non radiative recombination time is also calculated and found to be short (∼1 nsec). This is confirmed by some experiments on porous silicon which show a saturation effect of the photoluminescence under intense optical excitation or under cathodic polarization in aqueous solution, Auger recombination preventing the existence of more than one electron-hole pair per crystallite. Donor and acceptor impurities are studied in detail (screening of Coulomb potential, notion of ionization energy) with the conclusion that they are ionized. A final discussion shows the present level of understanding and identifies problems remaining to be solved.

Formation of Luminescent Si Nanocrystals by High-Temperature Annealing of Ion-Beam-Sputtered Si/SiO2 Multilayers

2003 ◽  
Vol 775 ◽  
Author(s):  
Suk-Ho Choi ◽  
Jun Sung Bae ◽  
Kyung Jung Kim ◽  
Dae Won Moon
Keyword(s):  
Quantum Confinement ◽  
Radiative Recombination ◽  
Ion Beam ◽  
Quantum Confinement Effect ◽  
Visible Range ◽  
Ion Beam Sputtering ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Beam Sputtering ◽  
Microscopy Images

AbstractSi/SiO2 multilayers (MLs) have been prepared under different deposition temperatures (TS) by ion beam sputtering. The annealing at 1200°C leads to the formation of Si nanocrystals in the Si layer of MLs. The high resolution transmission electron microscopy images clearly demonstrate the existence of Si nanocrystals, which exhibit photoluminescence (PL) in the visible range when TS is ≥ 300°C. This is attributed to well-separation of nanocrystals in the higher-TS samples, which is thought to be a major cause for reducing non-radiative recombination in the interface between Si nanocrystal and surface oxide. The visible PL spectra are enhanced in its intensity and are shifted to higher energy by increasing TS. These PL behaviours are consistent with the quantum confinement effect of Si nanocrystals.

Light Emission from Microcrystalline Si Confined in SiO2Matrix through Partial Oxidation of Anodized Porous Silicon

1992 ◽  
Vol 31 (Part 2, No.1A/B) ◽  
pp. L1-L3 ◽  
Author(s):  
Toshimichi Ito ◽  
Toshimichi Ohta ◽  
Akio Hiraki
Keyword(s):  
Porous Silicon ◽  
Partial Oxidation ◽  
Light Emission

Photoluminescence of Sm doped porous silicon—evidence for light emission through luminescence centers in SiO2layers

1994 ◽  
Vol 64 (24) ◽  
pp. 3282-3284 ◽  
Author(s):  
J. Lin ◽  
L. Z. Zhang ◽  
Y. M. Huang ◽  
B. R. Zhang ◽  
G. G. Qin
Keyword(s):  
Porous Silicon ◽  
Light Emission ◽  
Luminescence Centers

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.

Observation of quantum-confined luminescence in partially oxidized porous silicon

2000 ◽  
Vol 80 (4) ◽  
pp. 679-689 ◽  
Author(s):  
Giampiero Amato ◽  
L. Boarino ◽  
D. Midellino ◽  
A. M. Rossi
Keyword(s):  
Porous Silicon ◽  
Oxidized Porous Silicon ◽  
Quantum Confined

scholarly journals Two-dimensional photonic crystals increasing vertical light emission from Si nanocrystal-rich thin layers

2018 ◽  
Vol 9 ◽  
pp. 2287-2296
Author(s):  
Lukáš Ondič ◽  
Marian Varga ◽  
Ivan Pelant ◽  
Alexander Kromka ◽  
Karel Hruška ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Light Emission ◽  
Periodic Structures ◽  
Normal Direction ◽  
Thin Layers ◽  
Two Dimensional ◽  
Lattice Constants ◽  
Leaky Modes ◽  
Si Nanocrystals ◽  
Si Nanocrystal

We have fabricated two-dimensional photonic crystals (PhCs) on the surface of Si nanocrystal-rich SiO2 layers with the goal to maximize the photoluminescence extraction efficiency in the normal direction. The fabricated periodic structures consist of columns ordered into square and hexagonal pattern with lattice constants computed such that the red photoluminescence of Si nanocrystals (SiNCs) could couple to leaky modes of the PhCs and could be efficiently extracted to surrounding air. Samples having different lattice constants and heights of columns were investigated in order to find the configuration with the best performance. Spectral overlap of the leaky modes with the luminescence spectrum of SiNCs was verified experimentally by measuring photonic band diagrams of the leaky modes employing angle-resolved spectroscopy and also theoretically by computing the reflectance spectra. The extraction enhancement within different spatial angles was evaluated by means of micro-photoluminescence spectroscopy. More than 18-fold extraction enhancement was achieved for light propagating in the normal direction and up to 22% increase in overall intensity was obtained at the spatial collection angle of 14°.

Strongly Superlinear Light Emission and Large Induced Absorption in Oxidized Porous Silicon Films

1998 ◽  
Vol 536 ◽  
Author(s):  
H. Koyama ◽  
P. M. Fauchet
Keyword(s):  
Porous Silicon ◽  
Thermal Effects ◽  
Light Emission ◽  
Laser Intensity ◽  
Excitation Intensity ◽  
Silicon Films ◽  
Free Standing ◽  
Induced Absorption ◽  
Cw Laser ◽  
Oxidized Porous Silicon

AbstractThe optical properties of oxidized free-standing porous silicon films excited by a cw laser have been investigated. It is found that samples oxidized at 800–950 °C show a strongly superlinear light emission at an excitation intensity of ∼10 W/cm2. This emission has a peak at 900–1100 nm and shows a blueshift as the oxidation temperature is increased. These samples also show a very large induced absorption, where the transmittance is found to decrease reversibly by ≤99.7 %.The induced absorption increases linearly with increasing pump laser intensity. Both the superlinear emission and the large induced absorption are quenched when the samples are attached to materials with a higher thermal conductivity, suggesting that laser-induced thermal effects are responsible for these phenomena.

LUMINESCENCE BEHAVIOR AND MECHANISM OF LIGHT-EMITTING POROUS SILICON

1994 ◽  
Vol 08 (02) ◽  
pp. 69-92 ◽  
Author(s):  
XUN WANG
Keyword(s):  
Porous Silicon ◽  
Blue Light ◽  
Light Emission ◽  
Energy State ◽  
Surface Recombination Velocity ◽  
Luminescence Spectroscopy ◽  
Carrier Injection ◽  
Blue Light Emission ◽  
Light Emitting ◽  
Si Nanostructures

In this review article, we give a new insight into the luminescence mechanism of porous silicon. First, we observed a “pinning” characteristic of photoluminescent peaks for as-etched porous silicon samples. It was explained as resulting from the discontinuous variation of the size of Si nanostructures, i.e. the size quantization. A tight-binding calculation of the energy band gap widening versus the dimension of nanoscale Si based on the closed-shell Si cluster model agrees well with the experimental observations. Second, the blue-light emission from porous silicon was achieved by using boiling water treatment. By investigating the luminescence micrographic images and the decaying behaviors of PL spectra, it has been shown that the blue-light emission is believed to be originated from the porous silicon skeleton rather than the surface contaminations. The conditions for achieving blue light need proper size of Si nanostructures, low-surface recombination velocity, and mechanically strong skeleton. The fulfillment of these conditions simultaneously is possible but rather critical. Third, the exciton dynamics in light-emitting porous silicon is studied by using the temperature-dependent and picosecond time-resolved luminescence spectroscopy. A direct evidence of the existence of confined excitons induced by the quantum size effect has been revealed. Two excitation states are found to be responsible for the visible light emission, i.e. a higher lying energy state corresponding to the confined excitons in Si nanostructures and a lower lying state related with surfaces of Si wires or dots. A picture of the carrier transfer between the quantum confined state and the surface localized state has been proposed. Finally, we investigated the transient electroluminescence behaviors of Au/porous silicon/Si/Al structure and found it is very similar to that of an ordinary p-n junction light-emitting diode. The mechanism of electroluminescence is explained as the carrier injection through the Au/porous silicon Schotky barrier and the porous silicon/p-Si heterojunction into the corrugated Si wires, where the radiative recombination of carriers occurs.

Interface transfer processes and spectral hole burning in CdSe quantum confined clusters

1992 ◽  
Vol 117 (1-4) ◽  
pp. 608-613 ◽  
Author(s):  
U. Woggon ◽  
I. Rückmann ◽  
J. Kornack ◽  
M. Müller ◽  
J. Cesnulevicius ◽  
...  
Keyword(s):  
Hole Burning ◽  
Spectral Hole Burning ◽  
Transfer Processes ◽  
Spectral Hole ◽  
Quantum Confined
Sign in / Sign up

Export Citation Format

Share Document