On Applicability of Time-Resolved Optical Techniques for Characterization of Differently Grown 3C-SiC Crystals and Heterostructures

2012 ◽  
Vol 711 ◽  
pp. 159-163 ◽  
Author(s):  
Patrik Ščajev ◽  
Pavels Onufrijevs ◽  
Georgios Manolis ◽  
Mindaugas Karaliūnas ◽  
Saulius Nargelas ◽  
...  
Keyword(s):  
Room Temperature ◽  
Defect Density ◽  
Growth Conditions ◽  
Free Carrier ◽  
Band Edge Emission ◽  
Free Carrier Absorption ◽  
Free Standing ◽  
Optical Techniques ◽  
Time Resolved ◽  
Photoelectrical Properties

We applied a number of time-resolved optical techniques for investigation of optical and photoelectrical properties of cubic SiC grown by different technologies on different substrates. The excess carriers were injected by a short laser pulse and their dynamics was monitored by free-carrier absorption, light-induced transient grating, and photoluminescence techniques in a wide excitation range. Combining an optical and electrical probe beam delay, we found that free carrier lifetimes in differently grown layers vary from few ns up to 20 μs. Temperature dependences of carrier diffusivity and lifetime revealed a pronounced carrier trapping in thin sublimation grown layers. In free-standing layers and thick sublimation layers, the ambipolar mobility was found the highest (120 cm2/Vs at room temperature). A linear correlation between the room-temperature band edge emission and carrier lifetime in differently grown layers was attributed to defect density, strongly dependent on the used growth conditions.

scholarly journals Влияние условий роста и уровня легирования на кинетику люминесценции слоев Ge : Sb, выращенных на кремнии

2020 ◽  
Vol 54 (7) ◽  
pp. 685
Author(s):  
Д.В. Юрасов ◽  
Н.А. Байдакова ◽  
А.Н. Яблонский ◽  
А.В. Новиков
Keyword(s):  
Doping Level ◽  
Room Temperature ◽  
Carrier Lifetime ◽  
Growth Conditions ◽  
Published Data ◽  
Rapid Thermal Anneal ◽  
Time Resolved ◽  
Light Emitting ◽  
Pl Intensity ◽  
Time Resolved Photoluminescence

Light-emitting properties of Ge-on-Si(001) layers doped by Sb were studied by stationary and time-resolved photoluminescence (PL) at room temperature. It was obtained that the PL intensity of n-Ge/Si(001) structures is maximized when the doping level is close to the equilibrium solubility of Sb in Ge (~1019 cm-3) which is in accordance with the previously published data. Time-resolved studies of the direct-related PL signal have shown that both the donor density and the growth conditions of doped layer, in particular, the growth temperature influence the PL kinetics. It was obtained that the increase of doping level leads to the decrease of the characteristic carrier lifetime. Moreover, usage of low growth temperatures which is needed to form the doped n-Ge layers also results in shortening of the carrier lifetime as compared with Ge layers grown at high temperatures. It was found that rapid thermal anneal at proper conditions could partially compensate the above mentioned detrimental effects and lead to the increase of both the PL intensity and carrier lifetime.

Time-resolved measurement of free carrier absorption, diffusivity, and internal quantum efficiency in silicon

2013 ◽  
Vol 103 (9) ◽  
pp. 092101 ◽  
Author(s):  
Jet Meitzner ◽  
Frederick G. Moore ◽  
Brock M. Tillotson ◽  
Stephen D. Kevan ◽  
Geraldine L. Richmond
Keyword(s):  
Quantum Efficiency ◽  
Internal Quantum Efficiency ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Time Resolved ◽  
Carrier Absorption

Excitation-Wavelength Dependent and Time-Resolved Photoluminescence Studies of Europium Doped GaN Grown by Interrupted Growth Epitaxy (IGE)

2005 ◽  
Vol 866 ◽  
Author(s):  
Ei Ei Nyein ◽  
Uwe Hömmerich ◽  
Chanaka Munasinghe ◽  
Andrew J. Steckl ◽  
John M. Zavada
Keyword(s):  
Room Temperature ◽  
Growth Conditions ◽  
Excitation Wavelength ◽  
Time Resolved ◽  
Pl Intensity ◽  
Photoluminescence Studies ◽  
Two Peaks ◽  
Time Resolved Photoluminescence ◽  
Cycling Time ◽  
The Eu

AbstractThe emission properties of Eu doped GaN thin films prepared by interrupted growth epitaxy (IGE) were investigated through excitation-wavelength dependent and time-resolved photoluminescence (PL) studies. Under above-gap excitation (333-363 nm) large differences were observed in the Eu3+ PL intensity and spectral features as a function of Ga shutter cycling time. The overall strongest red Eu3+ PL intensity was obtained from a sample grown with a Gashutter cycling time of 20 minutes. The main Eu3+ emission line originating from 5D0→ 7F2 transition was composed of two peaks located at 620 nm and 622 nm, which varied in relative intensity depending on the growth conditions. The room-temperature emission lifetimes of the samples were non-exponential and varied from ∼50 νs to ∼200 νs (1/e lifetimes). Under resonant excitation at 471 nm (7F0→5D2) all samples exhibited nearly identical PL spectra independent of Ga shutter cycling time. Moreover, the Eu3+ PL intensities and lifetimes varied significantly less compared to above-gap excitation. The excitation wavelengths dependent PL results indicate the existence of different Eu3+ centers in GaN: Eu, which can be controlled by the Ga shutter cycling time.

High Quality Epitaxial Growth on 4° Off-Axis 4H SiC with Addition of HCl

2008 ◽  
Vol 600-603 ◽  
pp. 103-106 ◽  
Author(s):  
Jie Zhang ◽  
Janice Mazzola ◽  
Swapna G. Sunkari ◽  
Gray Stewart ◽  
Paul B. Klein ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Room Temperature ◽  
Carrier Lifetime ◽  
Defect Density ◽  
Free Exciton ◽  
High Quality ◽  
Pin Diodes ◽  
Time Resolved ◽  
Good Surface ◽  
Comprehensive Characterization

Epitaxial growth of 3-in, 4° off-axis 4H SiC with addition of HCl has been presented. Good surface morphology with a low defect density has been obtained, even for epi thickness of 38 µm. Comprehensive characterization techniques conducted on the epi material obtained in this process have independently confirmed the high purity and low density of crystalline imperfections. Low temperature PL displays clear free exciton I77 recombination while no L1 line is discernable. DLTS measurements have confirmed a low concentration of Z1/2 and EH6/7 below or in the range of 1011 cm-3. Time resolved PL at room temperature performed on a 38 µm thick epi wafer gives long carrier lifetime in the range of 1.5 to above 5 µsec. PiN diodes with diode area up to 25 mm2 have demonstrated blocking voltages above 900V, with a max electric field of above 2.5 MV/cm.

Band‐to‐band and free‐carrier absorption coefficients in heavily doped silicon at 4 K and at room temperature

1991 ◽  
Vol 69 (6) ◽  
pp. 3687-3690 ◽  
Author(s):  
S. C. Jain ◽  
A. Nathan ◽  
D. R. Briglio ◽  
D. J. Roulston ◽  
C. R. Selvakumar ◽  
...  
Keyword(s):  
Room Temperature ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Absorption Coefficients ◽  
Doped Silicon ◽  
Carrier Absorption ◽  
Heavily Doped

Optically Detected Temperature Dependences of Carrier Lifetime and Diffusion Coefficient in 4H- and 3C-SiC

2011 ◽  
Vol 679-680 ◽  
pp. 205-208 ◽  
Author(s):  
Jawad ul Hassan ◽  
Patrik Ščajev ◽  
Kęstutis Jarašiūnas ◽  
Peder Bergman
Keyword(s):  
Diffusion Coefficient ◽  
Decay Time ◽  
Carrier Lifetime ◽  
Free Carrier ◽  
Free Carrier Absorption ◽  
Time Resolved ◽  
Temperature Dependences ◽  
Carrier Absorption ◽  
Time Resolved Photoluminescence ◽  
And Diffusion

Free carrier dynamics has been studied in 4H- and 3C-SiC in a wide temperature range using time-resolved photoluminescence, free carrier absorption, and light induced transient grating techniques. Considerably high carrier lifetime was observed in 3C-SiC epitaxial layers grown on 4H-SiC substrates using hot-wall CVD with respect to previously reported values for 3C-SiC grown either on Si or on 6H-SiC substrates. The temperature dependences of carrier lifetime and diffusion coefficient for 4H- and 3C-SiC were compared. Shorter photoluminescence decay time with respect to free carrier absorption decay time was observed in the same 4H-SiC sample, while these techniques revealed similar trends in the carrier lifetime temperature dependencies. However, the latter dependences for hot-wall CVD-grown 3C layers were found different if measured by time resolved photoluminescence and free carrier absorption techniques.

Controlling Growth of InAs/GaAs Self-Assembled Quantum Dots to Give 1.3 μm Room Temperature Emission

1999 ◽  
Vol 571 ◽  
Author(s):  
Surama Malik ◽  
Philip Siverns ◽  
David Childs ◽  
Christine Roberts ◽  
Jean-Michel Hartmann ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Excited States ◽  
Room Temperature ◽  
Growth Parameters ◽  
High Growth ◽  
Growth Conditions ◽  
Time Resolved ◽  
Confining Potential ◽  
Decay Times ◽  
Self Assembled

ABSTRACTWe have investigated the extent to which the emission wavelength of self-assembled InAs/GaAs quantum dots can be controlled by growth parameters using conventional solid source MBE. Changing from conventionally high growth rates to a very low growth rate (LGR) and a relatively high substrate temperature, tunes the photoluminescence (PL) emission from 1.1 μm to 1.3 μm at room temperature. Atomic force micrographs obtained from uncapped samples reveal that these LGRQDs are larger, lower in density and extremely uniform in size. The improved size uniformity is reflected in the reduction of the PL linewidth from 78 meV to 22 meV. Under conditions of high excitation, emission from the ground and two excited states each separated by ∼70 meV is observed. This implies a parabolic confining potential. Time resolved photoluminescence (TRPL) measurements of dots grown under the various growth conditions yield radiative lifetimes which reflect the depth of the confining potential. A comparison of the decay times measured for the excited states show that the relaxation of carriers within the dots cannot be ascribed to phonon effects.

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