Size-dependent optical properties of Si nanocrystals embedded in amorphous SiO2 measured by spectroscopic ellipsometry

2011 ◽  
Vol 29 (4) ◽  
pp. 04D112 ◽  
Author(s):  
J. Wei ◽  
J. Price ◽  
T. Wang ◽  
C. Hessel ◽  
M. C. Downer
Keyword(s):  
Optical Properties ◽  
Spectroscopic Ellipsometry ◽  
Amorphous Sio2 ◽  
Size Dependent ◽  
Si Nanocrystals

Size-dependent donor and acceptor states in codoped Si nanocrystals studied by scanning tunneling spectroscopy

Nanoscale ◽  
2017 ◽  
Vol 9 (45) ◽  
pp. 17884-17892 ◽  
Author(s):  
Or Ashkenazi ◽  
Doron Azulay ◽  
Isaac Balberg ◽  
Shinya Kano ◽  
Hiroshi Sugimoto ◽  
...  
Keyword(s):  
Optical Properties ◽  
Semiconductor Nanocrystals ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Scanning Tunneling ◽  
Electrical And Optical Properties ◽  
Size And Shape ◽  
Size Dependent ◽  
Si Nanocrystals ◽  
Donor And Acceptor

The electrical and optical properties of semiconductor nanocrystals (NCs) can be controlled, in addition to size and shape, by doping.

Optical Properties Of Si Nanocrystals Formed In Si02 By Ion Implantation

1998 ◽  
Vol 507 ◽  
Author(s):  
C. W. White ◽  
S. P. Withrow ◽  
A. Meldrum ◽  
J. D. Budai ◽  
D. M. Hembree ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Ion Implantation ◽  
Quantum Confinement ◽  
Dose Dependence ◽  
Interface States ◽  
High Dose ◽  
Size Dependent ◽  
Si Nanocrystals

ABSTRACTSi nanocrystals formed in SiO2 by high-dose ion implantation and annealing give rise to strong optical absorption and intense photoluminescence (PL). The dose dependence of optical absorption provides evidence for size-dependent quantum confinement in the Si nanocrystals. PL peak energies are nearly independent of dose suggesting that surface or interface states play an important role in PL. Estimates of absorption bandgaps in the nanocrystals are given.

scholarly journals Optical Characterization of Ultra-Thin Films of Azo-Dye-Doped Polymers Using Ellipsometry and Surface Plasmon Resonance Spectroscopy

Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Najat Andam ◽  
Siham Refki ◽  
Hidekazu Ishitobi ◽  
Yasushi Inouye ◽  
Zouheir Sekkat
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Spectroscopic Ellipsometry ◽  
Plasmon Resonance ◽  
Complex Refractive Index ◽  
Resonance Spectroscopy ◽  
Doped Polymers

The determination of optical constants (i.e., real and imaginary parts of the complex refractive index (nc) and thickness (d)) of ultrathin films is often required in photonics. It may be done by using, for example, surface plasmon resonance (SPR) spectroscopy combined with either profilometry or atomic force microscopy (AFM). SPR yields the optical thickness (i.e., the product of nc and d) of the film, while profilometry and AFM yield its thickness, thereby allowing for the separate determination of nc and d. In this paper, we use SPR and profilometry to determine the complex refractive index of very thin (i.e., 58 nm) films of dye-doped polymers at different dye/polymer concentrations (a feature which constitutes the originality of this work), and we compare the SPR results with those obtained by using spectroscopic ellipsometry measurements performed on the same samples. To determine the optical properties of our film samples by ellipsometry, we used, for the theoretical fits to experimental data, Bruggeman’s effective medium model for the dye/polymer, assumed as a composite material, and the Lorentz model for dye absorption. We found an excellent agreement between the results obtained by SPR and ellipsometry, confirming that SPR is appropriate for measuring the optical properties of very thin coatings at a single light frequency, given that it is simpler in operation and data analysis than spectroscopic ellipsometry.

Synthesis and size control of Si nanocrystals by SiO/SiO2 superlattices and Er doping

2002 ◽  
Vol 737 ◽  
Author(s):  
J. Heitmann ◽  
D. Kovalev ◽  
M. Schmidt ◽  
L.X. Yi ◽  
R. Scholz ◽  
...  
Keyword(s):  
Phase Separation ◽  
Crystal Size ◽  
Radiative Lifetime ◽  
Size Control ◽  
Luminescence Signal ◽  
Er Doping ◽  
Size Dependent ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Ultrathin Layers

ABSTRACTThe synthesis of nc-Si by reactive evaporation of SiO and subsequent thermal induced phase separation is reported. The size control of nc-Si is realized by evaporation of SiO/SiO2 superlattices. By this method an independent control of crystal size and density is possible. The phase separation of SiO into SiO2 and nc-Si in the limit of ultrathin layers is investigated. Different steps of this phase separation are characterized by photoluminescence, infrared absorption and transmission electron microscopy measurements. The strong room temperature luminescence of nc-Si shows a strong blueshift of the photoluminescence signal from 850 to 750 nm with decreasing crystal size. Several size dependent properties of this luminescence signal, like decreasing radiative lifetime and increasing no-phonon transition properties with decreasing crystal size are in good agreement with the quantum confinement model. Er doping of the nc-Si shows an enhancement of the Er luminescence at 1.54 μm by a factor of 5000 compared to doped SiO2 layers. The decreasing transfer time for the nc-Si to Er transition with decreasing crystal size can be understood as additional proof of increasing recombination probability within the nc-Si for decreasing crystal size.

Sign in / Sign up

Export Citation Format

Share Document