Photoluminescence Characteristics of HF-Treated Silicon Nanocrystals

1996 ◽  
Vol 452 ◽  
Author(s):  
S. Nozaki ◽  
S. Sato ◽  
H. Ono ◽  
H. Morisaki
Keyword(s):  
Great Increase ◽  
Dangling Bonds ◽  
Porous Si ◽  
Helium Atmosphere ◽  
Pl Spectra ◽  
Si Nanocrystals ◽  
Evaporation Technique ◽  
Pl Intensity ◽  
Average Size ◽  
Gas Evaporation Technique

AbstractSi nanocrystals were deposited in a helium atmosphere by the gas-evaporation technique. Their average size is 3.5 nm, much smaller than those of the Si nanocrystals deposited in an argon atmosphere. The PL spectra of the as-deposited and the HF-treated Si nanocrystals were compared. A great increase in the PL intensity of the HF-treated Si nanocrystals is attributed to the hydrogen passivation of Si surface dangling bonds. A good correlation between the amount of Si-O bonds and the PL intensity suggests that the oxygen-passivation of dangling bonds is required for the red-band PL. The PL spectra of the HF-treated Si nanocrystals resemble those of porous Si and clearly indicate that the HF-treated Si nanocrystals well simulate the porous Si.

Influence of the Dispersion of the Size of the Si Nanocrystals on their Emission Spectra

1994 ◽  
Vol 358 ◽  
Author(s):  
J. B. Khurgin ◽  
E. W. Forsythe ◽  
S. I. Kim ◽  
B. S. Sywe ◽  
B. A. Khan ◽  
...  
Keyword(s):  
Systematic Study ◽  
Quantum Confinement ◽  
Emission Spectra ◽  
Emission Peak ◽  
Nanocrystal Size ◽  
Pl Spectra ◽  
Si Nanocrystals ◽  
Average Size ◽  
Size Dispersion ◽  
Confinement Model

ABSTRACTA systematic study of the PL spectra of Si quantum nanocrystals in the SiO2 matrix has been performed. The results have been fitted to a quantum-confinement model that includes the nanocrystal size dispersion rather than a specific size of the nanocrystal. This serves as a strong confirmation of the confinement-induced nature of the PL. It has been shown that if the dispersion is taken into account, the position of the emission peak as well as the PL width can always be correlated with the average size of the nanocrystal.

Optical Properties of Si Nanoclusters with Passivated Surfaces

1996 ◽  
Vol 431 ◽  
Author(s):  
L. N. Dinh ◽  
L. L. Chase ◽  
M. Balooch ◽  
W. J. Siekhaus ◽  
F. Wooten
Keyword(s):  
Blue Shift ◽  
Buffer Gas ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Pl Spectra ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Decay Times ◽  
Average Size

AbstractSi nanoclusters with average size of a few nanometers have been synthesized by thermal vaporization of Si in an Ar buffer gas, and passivated with oxygen or atomic hydrogen. High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) revealed that these nanoclusters were crystalline. All samples showed strong infrared and/or visible photoluminescence (PL) with varying decay times from nanoseconds to microseconds depending on synthesis conditions. Absorption mainly in the Si cores was observed by photoluminescence excitation (PLE) spectroscopy. The visible components of PL spectra were noted to blue shift and broaden as the size of the Si nanocrystals (nc-Si) was reduced, and there were differences in PL spectra for hydrogen and oxygen passivated nc-Si. Our data can be explained best by a model involving absorption between quantum confined states in the Si cores and emission by surface/interface states.

Transformation of optical properties of Si-rich Al2O3 films at thermal annealing

2013 ◽  
Vol 1617 ◽  
pp. 81-84
Author(s):  
E. Vergara Hernandez ◽  
B. Perez Miltan ◽  
J. Jedrzejewski ◽  
I. Balberg
Keyword(s):  
Optical Properties ◽  
Thermal Annealing ◽  
Peak Position ◽  
Pl Spectra ◽  
Glass Substrates ◽  
Si Nanocrystals ◽  
Temperature Dependences ◽  
Pl Intensity ◽  
Si Content ◽  
Al2o3 Films

ABSTRACTThe effect of thermal annealing on the optical properties of Al2O3 films with different Si content was investigated by the photoluminescence method. Si-rich Al2O3 films were prepared by RF magnetron co-sputtering of the silicon and alumina targets on long quarts glass substrates. Photoluminescence (PL) spectra of freshly prepared Si-rich Al2O3 films are characterized by three PL bands with the peak positions at 2.97-3.00, 2.25-2.29 and 1.50 eV. The thermal annealing of the films at 1150 °C during 30 min stimulates the formation of Si nanocrystals (NCs) in the film area with Si content exceeded 60%. After the thermal annealing the PL intensity of all mentioned PL bands decreases and the new PL band appears with the peak position at 1.67 eV. The new PL band is attributed to the photo currier recombination inside of Si NCs. The size of NCs estimated from the PL peak position 1.67 eV of Si NC emission is about ∼-4.5-5.0 nm.The temperature dependences of PL spectra of Si-rich Al2O3 films have been studied in the range of 10-300K with the aim to reveal the mechanism of recombination transitions for mentioned above PL bands 2.97-3.00, 2.25-2.29 and 1.50 eV in freshly prepared films. The thermal activation of PL intensity and permanent PL peak positions in the temperature range 10-300K permit to assign these PL bands to defect related emission in Al2O3 matrix.

Photoluminescence from Ge/Si Nanocrystals Embedded in Silicon Oxide Matrix Annealed in Hydrogen Gas

2008 ◽  
Vol 1145 ◽  
Author(s):  
Shin-ichiro Uekusa ◽  
Naoki Kosaka
Keyword(s):  
Thin Films ◽  
Silicon Oxide ◽  
Main Peak ◽  
Pl Spectra ◽  
Temperature Range ◽  
V Band ◽  
Si Nanocrystals ◽  
Oxide Matrix ◽  
Pl Intensity ◽  
Ar Gas

AbstractPhotoluminescence (PL) spectra from Si nanocrystals embedded in silicon oxide matrix (Si-SiO2) thin films, Ge embedded in silicon oxide matrix (Ge-SiO2) thin films and both Ge and Si embedded in silicon oxide matrix (Ge/Si-SiO2) thin films prepared by RF magnetron sputtering were investigated. All as-deposited thin films were annealed for 1h in the temperature range from 500°C to 1100°C in Ar or H2 atmosphere. The PL spectra of Si-SiO2 thin films exhibited red luminescence at an annealing temperature of 1100°C and the PL intensity of the sample annealed in H2 gas increased by a factor of approximately 6.3 in comparison with sample annealed in Ar gas. Subsequently, The PL intensity of main peak centered at about 400 nm (V-band) of Ge-SiO2 thin films annealed in H2 gas exhibited strong comparison with the sample annealed in Ar gas. Finally, the PL spectra of Ge/Si-SiO2 thin films exhibited strong peak centered at approximately 500-530 nm (G-band) besides V-band and others in the temperature range from 700°C to 1000°C. The PL intensity of G-band of the samples annealed in H2 gas exhibited weak comparison with Ar gas.

Capacitance-Voltage (C-V) Hysteresis in the Metal-Oxide-Semiconductor Capacitor with Si Nanocrystals Deposited by the Gas Evaporation Technique

2001 ◽  
Vol 686 ◽  
Author(s):  
Puspashree Mishra ◽  
Shinji Nozaki ◽  
Ryuta Sakura ◽  
Hiroshi Morisaki ◽  
Hiroshi Ono ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Supersonic Jet ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Flat Band ◽  
Mos Capacitor ◽  
Si Nanocrystals ◽  
Capacitance Voltage ◽  
Evaporation Technique ◽  
Gas Evaporation Technique

AbstractCapacitance-Voltage (C-V) hysteresis was observed in the Metal-Oxide-Semiconductor (MOS) capacitor with silicon nanocrystals. The MOS capacitor was fabricated by thermal oxidation of Si nanocrystals, which were deposited on an ultra-thin thermal oxide grown previously on a p-type Si substrate. The Si nanocrystals were deposited by the gas evaporation technique with a supersonic jet nozzle. The size uniformity and the crystallinity of the Si nanocrystals are found to be better than those fabricated by the conventional gas evaporation technique. The C-V hysteresis in the MOS capacitor is attributed to electron charging and discharging of the nanocrystals by direct tunneling though the ultra-thin oxide between the nanocrystals and the substrate. The flat-band voltage shift observed during the C-V measurement depends on the size and density of the nanocrystals and also on the magnitude of the positive gate bias for charging. The retention characteristic is also discussed.

Photoluminescence from n-(p-) type impurity doped Si nanocrystals

2000 ◽  
Vol 638 ◽  
Author(s):  
Minoru Fujii ◽  
Atsushi Mimura ◽  
Shinji Hayashi ◽  
Dmitri Kovalev ◽  
Frederick Koch
Keyword(s):  
Free Electrons ◽  
Electron Hole ◽  
P Concentration ◽  
Si Nanocrystals ◽  
Donor And Acceptor ◽  
Impurity Doped ◽  
Pl Intensity ◽  
B Doping ◽  
Three Body ◽  
P Type

AbstractEffects of impurity (P and B) doping on the photoluminescence (PL) properties of Si nanocrystals (nc-Si) in SiO2 thin films are studied. It is shown that with increasing P concentration, PL intensity first increases and then decreases. In the P concentration range where PL intensity increases, quenching of the defect-related PL is observed, suggesting that dangling-bond defects are passivated by P doping. On the other hand, in the range where PL intensity decreases, optical absorptiondue to the intravalley transitions of free electrons generated by P doping appears. The generation of free electrons andthe resultant three-body Auger recombination of electron-hole pairs is considered to be responsible for theobserved PL quenching. In the case of B doping, the behavior is much different. With increasing B concentration, PL intensity decreases monotonously. By combining the results obtained for P and B doped samples, theeffects of donor and acceptor impurities on the PL properties of nc-Si are discussed.

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