Time-Resolved Photoluminescence of CD(1-x)MN(x)SE and CD(1-x)MN(x)TE as a Function of Temperature

1986 ◽  
Vol 89 ◽  
Author(s):  
J. J. zayhowski ◽  
R. N. Kershaw ◽  
D. Ridgley ◽  
K. Dwight ◽  
A. Wold ◽  
...  
Keyword(s):  
Simple Model ◽  
Low Temperatures ◽  
Radiative Lifetime ◽  
Formation Time ◽  
Threshold Temperature ◽  
Magnetic Polaron ◽  
Time Resolved ◽  
Radiative Efficiency ◽  
Magnetic Polarons ◽  
Time Resolved Photoluminescence

AbstractThe characteristics of the photoluminescence of Cd(1-x)Mn(x)Se (x = 0.05, 0.10, 0.20, 0.30) and Cd(1-x)Mn(x)Te (x = 0.20, 0.30, 0.45) change considerably as the sample temperature is reduced below the exciton-magnetic polaron (EMP) threshold temperature. At low temperatures the formation of magnetic polarons has large effects on the luminescence energy, the radiative lifetime, the radiative efficiency, and the spectral half-width of the luminescence. It is also observed that the formation time of the EMP increases almost linearly with temperature. All of these effects are explained with a simple model for the EMP.

Exciton Lifetimes in GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
J.P. Bergman ◽  
C. Harris ◽  
B. Monemar ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Decay Time ◽  
Low Temperatures ◽  
Radiative Recombination ◽  
Radiative Lifetime ◽  
Free Exciton ◽  
Time Resolved ◽  
A Value ◽  
Donor And Acceptor ◽  
Exciton Recombination ◽  
Time Resolved Photoluminescence

ABSTRACTWe have performed time resolved photoluminescence measurements of the exciton recombination in different GaN samples at low temperatures. In epitaxial layers the decay time of the free exciton is typically faster than 100 ps. This is due to a dominating non-radiative recombination process. In thick bulk samples we have resolved and measured the decay time of the free exciton with a value of about 200 ps. We believe that this value is close to the radiative lifetime for free excitons in GaN. We have also shown that excitation transfer occurs between free and bound exciton states. We have furthermore measured the decay of the donor and acceptor bound excitons, and obtained values of the decay time of 250 ps and 1200 ps, respectively.

SELF-TRAPPED EXCITONS IN ORTHORHOMBIC SnBr2

2001 ◽  
Vol 15 (28n30) ◽  
pp. 4009-4012 ◽  
Author(s):  
Y. YAMASAKI ◽  
N. OHNO
Keyword(s):  
Time Dependence ◽  
Low Temperatures ◽  
Luminescence Band ◽  
Radiative Decay ◽  
Time Resolved ◽  
Tunneling Recombination ◽  
Exciton Region ◽  
Time Resolved Photoluminescence ◽  
Stokes Shifts ◽  
2.5 Ev Luminescence

Luminescence properties of SnBr 2 have been studied to reveal the photo-excited exciton relaxation process. Two types of luminescence with large Stokes shifts are found at low temperatures; the 2.2-eV luminescence band produced under the photo-excitation in the first exciton region, and the 2.5-eV luminescence band stimulated by photons with energies above the bandgap. The time-resolved photoluminescence measurements have revealed that the 2.2-eV luminescence comprises fast (1.2 μs) and slow (6.4 μs) exponential decay components, whereas the 2.5-eV luminescence shows the time dependence of I(t)∞ t-0.9. These results suggest that the former band is attributed to the radiative decay of self-trapped excitons, and the latter band would originate from tunneling recombination of holes with the STEL as in the case of lead halides.

UNDERSTANDING ULTRAVIOLET EMITTER PERFORMANCE USING INTENSITY DEPENDENT TIME-RESOLVED PHOTOLUMINESCENCE

2007 ◽  
Vol 17 (01) ◽  
pp. 179-188 ◽  
Author(s):  
MICHAEL WRABACK ◽  
GREGORY A. GARRETT ◽  
ANAND V. SAMPATH ◽  
PAUL H. SHEN
Keyword(s):  
Radiative Lifetime ◽  
Active Regions ◽  
Pump Intensity ◽  
Performance Comparison ◽  
Nonradiative Recombination ◽  
Extended Defects ◽  
Light Emitters ◽  
Time Resolved ◽  
Photoluminescence Studies ◽  
Time Resolved Photoluminescence

Time-resolved photoluminescence studies of nitride semiconductors and ultraviolet light emitters comprised of these materials are performed as a function of pump intensity as a means of understanding and evaluating device performance. Comparison of time-resolved photoluminescence (TRPL) on UV LED wafers prior to fabrication with subsequent device testing indicate that the best performance is attained from active regions that exhibit both reduced nonradiative recombination due to saturation of traps associated with point and extended defects and concomitant lowering of radiative lifetime with increasing carrier density. Similar behavior is observed in optically pumped UV lasers. Temperature and intensity dependent TRPL measurements on a new material, AlGaN containing nanoscale compositional inhomogeneities (NCI), show that it inherently combines inhibition of nonradiative recombination with reduction of radiative lifetime, providing a potentially higher efficiency UV emitter active region.

Time-Resolved Photoluminescence of GaN / Ga0.93Al0 .07N Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
P. Lefebvre ◽  
J. Allègre ◽  
B. Gil ◽  
A. Kavokine ◽  
H. Mathieu ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Lifetime ◽  
Temperature Limit ◽  
Multiple Quantum ◽  
Carrier Localization ◽  
Substantial Variation ◽  
Time Resolved ◽  
Potential Fluctuations ◽  
Alloy Disorder ◽  
Time Resolved Photoluminescence

AbstractThe recombination dynamics of excitons in GaN / Ga0.93Al0.07N multiple quantum wells is studied versus lattice temperature. The average decay time of photoluminescence measured at 8K is of ∼330 ps, with a substantial variation of times within the emission line. This is interpreted in terms of carrier localization due to alloy disorder and to well width and depth variations. The radiative lifetime τr of excitons in the wells is found to increase linearly with temperature, with ∂τr / ∂T = 20.5 ± 0.7 ps.K−1. The radiative lifetime of free excitons in the low-temperature limit is deduced to be 2.4 ps, consistent with a longitudinal-transverse splitting ћωLT in GaN of 0.6 meV, in excellent agreement with recent estimations. The ratio of the lifetimes of localized and free excitons is found coherent with the picture of electrons and holes independently localized on short-range defects, instead of excitons localized as a whole on long-range potential fluctuations.

Recombination Dynamics of Surface-Related Excitonic States in Single ZnO Nanowires

2008 ◽  
Vol 8 (1) ◽  
pp. 228-232 ◽  
Author(s):  
Tobias Voss ◽  
Lars Wischmeier
Keyword(s):  
Low Temperatures ◽  
Optical Spectra ◽  
Semiconductor Nanowires ◽  
Emission Lines ◽  
Time Resolved ◽  
Photoluminescence Studies ◽  
Different Diameters ◽  
Excitonic States ◽  
Time Resolved Photoluminescence ◽  
Recombination Dynamics

With decreasing diameter the influence of surface-related effects becomes increasingly important for an understanding of the optical properties of semiconductor nanowires. We present time integrated and time resolved photoluminescence studies of single zincoxide nanowires with different diameters. We analyze the changes in the optical spectra for wires with different surface-to-volume ratios, present optical spectra of single wires at different excitation densities, and study the time-resolved dynamics of the surface related and donor-bound exciton related emission lines for a single nanowire at low temperatures.

Picosecond time-resolved photoluminescence studies of exciton-magnetic polaron complexes in Cd1−xMnxSe

1985 ◽  
Vol 55 (11) ◽  
pp. 941-945 ◽  
Author(s):  
J.J. Zayhowski ◽  
C. Jagannath ◽  
R.N. Kershaw ◽  
D. Ridgley ◽  
K. Dwight ◽  
...  
Keyword(s):  
Magnetic Polaron ◽  
Time Resolved ◽  
Photoluminescence Studies ◽  
Time Resolved Photoluminescence

EXCITON LOCALIZATION IN (Cd,Zn)O EPILAYERS AND (Cd,Zn)O/(Mg,Zn)O MULTI-QUANTUM WELLS ON LATTICE-MATCHED SUBSTRATES

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3853-3856 ◽  
Author(s):  
T. MAKINO ◽  
N. T. TUAN ◽  
C. H. CHIA ◽  
Y. SEGAWA ◽  
M. KAWASAKI ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Molecular Beam ◽  
Radiative Lifetime ◽  
Phonon Coupling ◽  
Time Resolved ◽  
Exciton Localization ◽  
Photoluminescence Studies ◽  
Time Resolved Photoluminescence ◽  
Lattice Matched

We report on optical properties of epitaxial (Cd,Zn)O layers and multi-quantum wells grown by laser molecular-beam epitaxy on lattice-matched ScAlMgO 4 substrates. Exciton-phonon coupling strength in (Cd,Zn)O layers estimated by temperature dependence of the excitonic energy was similar to that deduced in ZnO . Time-resolved photoluminescence studies were performed on the multi-quantum wells, which are almost perfectly lattice-matched (0.034%). Radiative recombination of excitons exhibits a spectral distribution of times. We found that the radiative lifetime increases linearly with temperature, showing a two-dimensional feature of excitons in quantum wells.

Time Resolved Photoluminescence of Yb in InP

1987 ◽  
Vol 104 ◽  
Author(s):  
P. B. Klein
Keyword(s):  
Activation Energy ◽  
Valence Band ◽  
Low Temperatures ◽  
Weak Coupling ◽  
Thermal Activation ◽  
Thermal Activation Energy ◽  
Excited State Lifetime ◽  
Time Resolved ◽  
Exponential Component ◽  
Time Resolved Photoluminescence

ABSTRACTTime resolved photoluminescence (PL) measurements of the internal 4f-4f transitions of Yb3+ have been carried out in InP and GaP. In InP a nonexponential component is observed in the PL decay, and is interpreted in terms of carrier capture by nonequilibrium Yb3+. At low temperatures the exponential component is found to be much faster (≈12.5 μsec) than expected, and is tentatively associated with a weak coupling to resonant valence band states. As the temperature is increased, the PL intensity and the exponential component of the excited state lifetime are quenched with a thermal activation energy of ≈0.1 eV. This is interpreted as being due to the emission of a hole into the valence band by the neutral Yb acceptor.

Time Resolved Photoluminescence Spectroscopy on GaN Epitaxial Layers

1995 ◽  
Vol 378 ◽  
Author(s):  
B. K. Meyer ◽  
D. Volm ◽  
C. Wetzel ◽  
L. Eckey ◽  
J.-Ch. Holst ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Photoluminescence Spectroscopy ◽  
Epitaxial Layers ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Sapphire Substrates ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
Time Resolved Photoluminescence

AbstractFree and bound exciton luminescences as well as donor-acceptor pair recombination of GaN epitaxial layers on 6H-SiC and sapphire substrates were investigated using time integrated and time resolved photoluminescence measurements at low temperatures. Lifetimes are determined for the donor bound exciton at 3.4722eV and for two acceptor bound excitons with energies of 3.4672eV and 3.459eV. Luminescences between 3.29eV and 3.37eV are identified as due to excitons deeply bound to centers located near the substrate-epilayer interface.

Sign in / Sign up

Export Citation Format

Share Document