Carrier Dynamics in Porous Silicon: from the Femtosecond to the Second

1994 ◽  
Vol 358 ◽  
Author(s):  
Philippe M. Fauchet
Keyword(s):  
Porous Silicon ◽  
Time Domain ◽  
Room Temperature ◽  
Auger Recombination ◽  
Excitation Intensity ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
Oxidized Porous Silicon ◽  
Red Luminescence ◽  
Absorption Measurements

ABSTRACTThe luminescence in red-emitting porous silicon exhibits a distribution of lifetimes in the μsec time domain at room temperature and in the msec time domain at cryogenic temperatures. However, the luminescence and carrier dynamics in porous silicon display transients that vary from much less than 1 psec to ∼ 1 sec, depending on the measurement conditions and sample preparation. We have investigated the carrier dynamics in porous silicon by two time-resolved techniques. The blue photoluminescence of oxidized porous silicon has been measured with 100 ps time resolution as a function of the oxidation method, emission wavelength, excitation intensity and measurement temperature. The blue luminescence has a distinct origin from the well-studied red luminescence and we attribute it to defects in the oxide. Femtosecond photoinduced absorption measurements have been performed on thin red-emitting porous silicon films. The wavelength and intensity dependence of the recovery are interpreted in terms of trapping and of Auger recombination at high excitation intensity. Our results also show conclusively that red-emitting porous silicon is not a direct gap semiconductor.

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.

scholarly journals Ultrafast dynamics of a bi-stable azopyridine Ni-porphyrin spin switch after photoexcitation in the porphyrin B-bands

2019 ◽  
Vol 205 ◽  
pp. 05019
Author(s):  
Sebastian Megow ◽  
Julia Bahrenburg ◽  
Mark Dittner ◽  
Birthe Kohly ◽  
Joachim Gripp ◽  
...  
Keyword(s):  
High Spin ◽  
Room Temperature ◽  
Ultrafast Dynamics ◽  
Time Resolved ◽  
Spin Switch ◽  
Absorption Measurements

Femtosecond time-resolved absorption measurements of a magnetically bi-stable azopyridine Ni-porphyrin in solution at room temperature show that the photo-induced dynamics are dominated by transient low-spin ⇄ high-spin interconversion involving Ni (d2) and (d, d) states.

Fabrication of Macroporous Silicon in Organic Electrolytes and their Luminescence

2017 ◽  
Vol 748 ◽  
pp. 127-131 ◽  
Author(s):  
Wu Lin Li ◽  
Wen Jing Yang ◽  
Mei Long ◽  
Gen Rong Li ◽  
Yan Ma ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Electrochemical Process ◽  
Macroporous Silicon ◽  
Organic Solution ◽  
Organic Electrolytes ◽  
Red Luminescence ◽  
Organic Solutions ◽  
Side Illumination ◽  
Nanoporous Layer

The quasi-regular arrangements porous silicon was fabricated by by electrochemical process using organic solutions with front-side illumination, and SEM showed that the morphology of porous silicon was dependent sensitively on the current density, organic electrolytes and their concentration. The results indicate that N-dimethylformamide (DMF) is the best organic solution and quasi-regular arranged pores can be well organized in 20%HF/DMF solution. The luminescence shows fresh porous silicon can emit the red luminescence at room temperature and quench after nanoporous layer destroyed.

Picosecond carrier dynamics and studies of Auger recombination processes in indium arsenide at room temperature

1992 ◽  
Vol 46 (20) ◽  
pp. 13194-13200 ◽  
Author(s):  
K. L. Vodopyanov ◽  
H. Graener ◽  
C. C. Phillips ◽  
T. J. Tate
Keyword(s):  
Indium Arsenide ◽  
Room Temperature ◽  
Auger Recombination ◽  
Carrier Dynamics ◽  
Recombination Processes

Fast Photoluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
V. Petrova-Koch ◽  
T. Muschik ◽  
D. I. Kovalev ◽  
F. Koch ◽  
V. Lehmann
Keyword(s):  
Porous Silicon ◽  
Response Time ◽  
Spectral Range ◽  
Luminescence Band ◽  
Room Temperature ◽  
Internal Surface ◽  
Porous Si ◽  
Time Resolved ◽  
Processed Material ◽  
Defect Luminescence

ABSTRACTTime-resolved studies of the visible photoluminescence in porous silicon with three different coverages of the internal surface are reported. We use aged, naturally oxidized porous Si (oxihydride), rapid thermal processed material (oxide) and samples stored in HF (pure hydride). A new, fast luminescence band in the blue-green spectral range and with response time less than 100 ns is observed at room temperature in each of the samples, although with different intensities. The observations prove that this is not an oxide-defect luminescence. We speculate on mechanisms for the origin of the fast luminescence in nanometer-size crystallites of Si.

Temperature-dependent picosecond time-resolved carrier dynamics in visible-light-emitting porous silicon

1994 ◽  
Vol 91 (3) ◽  
pp. 239-243 ◽  
Author(s):  
Jian Wang ◽  
Wen-cheng Wang ◽  
Jia-biao Zheng ◽  
Fu-long Zhang ◽  
Xiao-yuan Hou ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Visible Light ◽  
Carrier Dynamics ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Light Emitting

Carrier dynamics in oxidized porous silicon

1996 ◽  
Vol 80 (3) ◽  
pp. 1749-1756 ◽  
Author(s):  
Shuji Komuro ◽  
Takashi Kato ◽  
Takitaro Morikawa ◽  
Patrick O’Keeffe ◽  
Yoshinobu Aoyagi
Keyword(s):  
Porous Silicon ◽  
Carrier Dynamics ◽  
Oxidized Porous Silicon

Room Temperature led's for the MID-Infrared Based on in(AS,SB) Strained Layer Superlattices

1996 ◽  
Vol 450 ◽  
Author(s):  
C. C. Phillips ◽  
P. J. P. Tang ◽  
M. J. Puliin ◽  
H. R. Hardaway ◽  
S. J. Chung ◽  
...  
Keyword(s):  
Room Temperature ◽  
Auger Recombination ◽  
Type Ii ◽  
Time Resolved ◽  
Mid Infrared ◽  
Strained Layer ◽  
Carrier Confinement ◽  
Strained Layer Superlattices

ABSTRACTArsenic-rich InAs/InAs1−x Sbx strained-layer superlattices (SLS's) are studied in time-resolved optical, and CW magneto-optical spectroscopies. A pronounced type-II offset, with electrons confined to the alloy layers, is found. High radiative efficiencies at wavelengths well into the mid-IR, and the suppression of Auger recombination yield LED's operating at 3–10 μm. Present room temperature powers are ∼30 μW, probably limited by inadequate carrier confinement.

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