Characterization of Visible and Infrared (1.54 μm) Luminescence from Er-doped Porous Si

1996 ◽  
Vol 422 ◽  
Author(s):  
R. White ◽  
X. Wu ◽  
U. Hömmerich ◽  
F. Namavar ◽  
A. M. Cremins-Costa
Keyword(s):  
Temperature Dependence ◽  
Photoluminescence Excitation ◽  
Porous Si ◽  
Pl Intensity ◽  
Si Nanostructures ◽  
Er Doped

AbstractResults of a photoluminescence excitation (PLE) study of Er-implanted porous Si (Er: PSi) are presented. Erbium was implanted at a dose of 1×1015 Er/cm2 at 380 keV and annealed for 30 minutes at 6507deg;C. We observed a nearly identical PLE intensity behavior from 1.54 μm and visible-emitting Er: PSi. This observation indicates that both visible and infrared photoluminescence (PL) arise from carrier mediated processes, and that the 1.54 μm Er3+ PL is related to the porous Si nanostructures. Measurements of the temperature dependence (15–375K) of Er3+ PL intensity and lifetime are also reported.

Characterization of Erbium Doped SiO2 Layers Formed On Silicon By Spark Processing

1997 ◽  
Vol 486 ◽  
Author(s):  
John V. St. John ◽  
Jeffery L. Coffer ◽  
Young Gyu Rho ◽  
Patrick Diehl ◽  
Russell F. Pinizzotto ◽  
...  
Keyword(s):  
Rare Earth ◽  
Porous Silicon ◽  
Porous Si ◽  
Rare Earth Ion ◽  
Temperature Oxidation ◽  
X Ray ◽  
Near Ir ◽  
Erbium Doped ◽  
Er Doped

AbstractDeposition of a rare earth salt layer on a silicon substrate with subsequent spark processing yields a porous Si layer and SiO 2 cap doped with the rare earth ion. We have characterized luminescent Er-doped porous SiO2 on Si by scanning electron microscopy, energy dispersive Xray spectroscopy, as well as visible and near IR photoluminescence (PL) spectroscopies. Energydispersive x-ray maps indicate that the erbium concentration in the porous layer can be controlled by varying the molarity of the erbium solution deposited on the substrate prior to spark processing. Visible PL measurements reveal that the concentration of Er3+ is proportional to the resultant intensity of the visible fluorescence transitions; however, for the near IR fluorescence peak at 1.54 gim, self-quenching due to erbium clustering occurs at higher concentrations. Erbium-doped porous silicon layers can also be obtained by diffusion of an erbium salt into porous silicon formed by anodic etching of Si in hydrofluoric acid. Densification of the porous Si layers through high temperature oxidation after erbium diffusion forms erbium-doped SiO2 layers.

Photoluminescence and photoluminescence excitation spectroscopy of Er-doped Si prepared by laser ablation

1999 ◽  
Vol 75 (1) ◽  
pp. 97-99 ◽  
Author(s):  
Wai Lek Ng ◽  
M. P. Temple ◽  
P. A. Childs ◽  
F. Wellhofer ◽  
K. P. Homewood
Keyword(s):  
Laser Ablation ◽  
Photoluminescence Excitation ◽  
Er Doped

Photoluminescence Excitation Spectroscopy of Carbon-Doped Gallium Nitride

1998 ◽  
Vol 537 ◽  
Author(s):  
E. E. Reuter ◽  
R. Zhang ◽  
T. F. Kuech ◽  
S. G. Bishop
Keyword(s):  
Complete Characterization ◽  
Photoluminescence Excitation ◽  
Yellow Luminescence ◽  
Broad Excitation Band ◽  
Carbon Doped ◽  
Sapphire Substrates ◽  
Red Luminescence ◽  
Unusual Shape

AbstractWe have done a comparative study of carbon-doped GaN and undoped GaN utilizing photoluminescence (PL) and photoluminescence excitation (PLE) spectroscopies in order to investigate deep levels involved in yellow luminescence (YL) and red luminescence (RL). When the GaN was excited by above-bandgap light, red luminescence (RL) centered at 1.82 eV was the dominant below-gap PL from undoped GaN, but carbon-doped GaN below-gap PL was dominated by yellow luminescence (YL) centered at 2.2 eV. When exciting PL below the band-gap with 2.4 eV light, undoped GaN had a RL peak centered at 1.5 eV and carbon-doped GaN had a RL peak centered at 1.65 eV. PLE spectra of carbon-doped GaN, detecting at 1.56 eV, exhibited a strong, broad excitation band extending from about 2.1 to 2.8 eV with an unusual shape that may be due to two or more overlapping excitation bands. This RL PLE band was not observed in undoped GaN. We also demonstrate that PL spectra excited by below gap light in GaN films on sapphire substrates are readily contaminated by 1.6-1.8 eV and 2.1-2.5 eV chromium-related emission from the substrate. A complete characterization of the Cr emission and excitation bands for sapphire substrates enables the determination of the excitation and detection wavelengths required to obtain GaN PL and PLE spectra that are free of contributions from substrate emission.

Preparation and Characterization of Porous Si-Coated SiC Fiber Media

2004 ◽  
Vol 449-452 ◽  
pp. 233-236 ◽  
Author(s):  
Jun Suh Yu ◽  
B.S. Lee ◽  
Sung Churl Choi ◽  
Ji Hun Oh ◽  
Jae Chun Lee
Keyword(s):  
Electrical Conductivity ◽  
Silicon Content ◽  
Porous Si ◽  
Electrically Conductive ◽  
Electrode Distance ◽  
Sic Fiber ◽  
Effective Electrical Conductivity ◽  
The One ◽  
Fiber Preforms

Electrically conductive porous Si/SiC fiber media were prepared by infiltration of liquid silicon into porous carbon fiber preforms. The series rule of mixture for the effective electrical conductivity was applied to the disc shaped samples to estimate their silicon content, effective electrical conductivity and porosity. The electrical conductivity was estimated by assuming the disc sample as a plate of equivalent geometry, i.e., same thickness, electrode distance and volume. As the volumetric content of silicon in a sample increases from 0.026% to 0.97%, the estimated electrical conductivity increases from 0.17 S/cm to 2.09 S/cm. The porosity of the samples measured by Archimedes principle was in the range of 75~83% and 1~4% less than the one estimated by the series rule of mixture for the effective electrical conductivity.

scholarly journals Dynamics of Anomalous Temperature-Induced Emission Shift in MOCVD-grown (Al, In)GaN Thin Films

2000 ◽  
Vol 5 (S1) ◽  
pp. 796-802 ◽  
Author(s):  
Yong-Hoon Cho ◽  
G. H. Gainer ◽  
J. B. Lam ◽  
J. J. Song ◽  
W Yang ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Stokes Shift ◽  
Energy Shift ◽  
Peak Position ◽  
Time Resolved ◽  
Temperature Range ◽  
Al Content ◽  
Peak Energy ◽  
Emission Behavior ◽  
Pl Intensity

We present a comprehensive study of the optical characteristics of (Al, In)GaN epilayers measured by photoluminescence (PL), integrated PL intensity, and time-resolved PL spectroscopy. For not only InGaN, but also AlGaN epilayers with large Al content, we observed an anomalous PL temperature dependence: (i) an “S-shaped” PL peak energy shift (decrease-increase-decrease) and (ii) an “inverted S-shaped” full width at half maximum (FWHM) change (increase-decrease-increase) with increasing temperature. Based on time-resolved PL, the S shape (inverted S shape) of the PL peak position (FWHM) as a function of temperature, and the much smaller PL intensity decrease in the temperature range showing the anomalous emission behavior, we conclude that strong localization of carriers occurs in InGaN and even in AlGaN with rather high Al content. We observed that the following increase with increasing Al content in AlGaN epilayers: (i) a Stokes shift between the PL peak energy and the absorption edge, (ii) a redshift of the emission with decay time, (iii) the deviations of the PL peak energy, FWHM, and PL intensity from their typical temperature dependence, and (iv) the corresponding temperature range of the anomalous emission behavior. This indicates that the band-gap fluctuation responsible for these characteristics is due to energy tail states caused by non-random inhomogeneous alloy potential variations enhanced with increasing Al content.

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