TIME-RESOLVED PHOTOLUMINESCENCE OF EXCITONS IN HgI2

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3920-3923 ◽  
Author(s):  
N. OHNO ◽  
X. M. WEN
Keyword(s):  
Radiative Recombination ◽  
Luminescence Band ◽  
Broad Band ◽  
Relaxation Processes ◽  
Time Resolved ◽  
Carrier Lifetimes ◽  
Broad Luminescence Band ◽  
Donor Acceptor ◽  
Exciton Annihilation ◽  
Time Resolved Photoluminescence

The time-resolved photoluminescence (TRPL) of red HgI 2 single crystal has been measured to determine the carrier lifetimes and to reveal the energy relaxation of excitons. Sharp near-bandgap luminescence lines due to free and bound excitons are observed at 530 nm, and a broad luminescence band appears at 630 nm at low temperatures. TRPL experiments of the near-bandgap luminescence have revealed that the luminescence comprise fast (30 to 200 ps) and slow (100 to 400 ps) decay components, showing several relaxation processes in free and bound exciton annihilation. TRPL of the broad band at 630 nm has shown that the luminescence is ascribed to the radiative recombination of donor-acceptor (DA) pairs.

Defects in bulk ZnO studied by steady-state and time-resolved photoluminescence

2007 ◽  
Vol 1035 ◽  
Author(s):  
Michael A. Reshchikov
Keyword(s):  
Broad Band ◽  
Peak Position ◽  
Pulse Excitation ◽  
Time Interval ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Nonexponential Decay ◽  
Donor Acceptor ◽  
Pl Spectrum ◽  
Time Resolved Photoluminescence

AbstractUnintentionally doped bulk ZnO samples were grown by hydrothermal method in Tokyo Denpa Co. Ltd. (Japan) and MTI Corporation. At low temperatures the PL spectrum contained a very broad band with the peak position (between 2.0 and 2.4 eV) depending on the excitation intensity. Evolution of the PL spectrum after a pulse excitation revealed that the broad band is composed of an orange (OL) and green (GL) luminescence bands having maxima at 1.96 and ∼2.35 eV, respectively. The GL band dominated at times up to 1 ms and then disappeared. The OL band decayed as approximately t−1 over a wide time interval, and its spectrum could be recorded even 24 hours after the excitation source was switched off. The slow nonexponential decay of the OL band is attributed to transitions from shallow donors to a deep acceptor (donor-acceptor pair transitions).

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.

Robust single-mode lasers based on hexagonal CdS microflakes

2020 ◽  
Vol 8 (32) ◽  
pp. 11201-11208
Author(s):  
Yang Mi ◽  
Yaoyao Wu ◽  
Jinchun Shi ◽  
Sheng-Nian Luo
Keyword(s):  
Radiative Recombination ◽  
Single Mode ◽  
Whispering Gallery Mode ◽  
Radiative Recombination Rate ◽  
Electron Hole ◽  
High Quality ◽  
Time Resolved ◽  
Whispering Gallery ◽  
Electron Hole Plasma ◽  
Time Resolved Photoluminescence

We have achieved single-mode whispering-gallery-mode lasing in CdS microflakes with sharp linewidth (∼0.12 nm) and high quality factor (∼4200). Such lasers are superior to previous CdS lasers in these lasing parameters. Through time-resolved photoluminescence measurements, electron–hole plasma recombination is established to be the lasing mechanism. The radiative recombination rate of CdS microflakes is enhanced by a factor of ∼4.7 due to the Purcell effect.

scholarly journals Defect Characterization in ZnGeP2 by Time -Resolved Photoluminescence

1996 ◽  
Vol 450 ◽  
Author(s):  
N. Dietz ◽  
W. Busse ◽  
H. E. Gumlich ◽  
W. Ruderman ◽  
I. Tsveybak ◽  
...  
Keyword(s):  
Energy Range ◽  
Infrared Emission ◽  
Luminescence Spectra ◽  
Broad Emission Band ◽  
Wide Energy Range ◽  
Time Resolved ◽  
Broad Emission ◽  
Donor Acceptor ◽  
Donor States ◽  
Time Resolved Photoluminescence

AbstractSteady state and time-resolved photoluminescence (PL) investigations on ZnGeP2 crystals grown from the vapor phase by high pressure physical vapor transport (HPVT) and from the melt by gradient freezing (GF) are reported. The luminescence spectra reveal a broad infrared emission with peak position at 1.2 eV that exhibits features of classical donor-acceptor recombination. The hyperbolic decay characteristic over a wide energy range, investigated from 1.2 eV up to 1.5eV, suggest that this broad emission band is related to one energetic recombination center. Higher energetic luminescence structures at 1.6eV and 1.7eV were revealed after annealing of ZnGeP2 crystals in vacuum for a longer period of time. The emission decay behavior in this energy range is characterized by two hyperbolic time constants, viewed as the supercomposition of the decay from the broad emission center peaked at 1.2eV and additional donor-acceptor recombination emissions at 1.6eV and 1.7eV, respectively. ZnGeP2 crystals grown under Ge-deficient conditions by HPVT show an additional emission structure at 1.8 eV with sharp emission fine structures at 1.778 eV related to the presence of additional donor states.

Time-resolved photoluminescence in CdIn2S4

1987 ◽  
Vol 65 (3) ◽  
pp. 204-207 ◽  
Author(s):  
S. Charbonneau ◽  
E. Fortin ◽  
J. Beauvais
Keyword(s):  
Single Crystals ◽  
Free Electron ◽  
Continuous Wave ◽  
Time Window ◽  
Photoluminescence Spectra ◽  
Time Resolved ◽  
Spectral Bands ◽  
Window Technique ◽  
Donor Acceptor ◽  
Time Resolved Photoluminescence

Photoluminescence spectra of CdIn2S4 single crystals at 1.8 K under both continuous-wave (CW) and pulsed excitation were obtained. In the latter case, a variable time-window technique was used to observe the time evolution of the spectra between 0 and 100 μs. In contrast to previous studies, four spectral bands were observed under both CW and pulsed, intrinsic or extrinsic excitation. In particular, two bands previously unobserved under extrinsic excitation were detected at 1.35 and 1.68 eV, and have been attributed to donor–acceptor pairs and free-electron to acceptor transitions respectively.

scholarly journals Localized Surface Plasmon on 6H SiC with Ag Nanoparticles

2017 ◽  
Vol 897 ◽  
pp. 634-637
Author(s):  
Yi Wei ◽  
Ahmed Fadil ◽  
Hai Yan Ou
Keyword(s):  
Ag Nanoparticles ◽  
Internal Quantum Efficiency ◽  
Minority Carrier Lifetime ◽  
Fdtd Simulation ◽  
Localized Surface Plasmon ◽  
Ag Nanoparticle ◽  
Ag Nps ◽  
Time Resolved ◽  
Donor Acceptor ◽  
Time Resolved Photoluminescence

Silver (Ag) nanoparticles (NPs) were deposited on the surface of bulk Nitrogen-Boron co-doped 6H silicon carbide (SiC), and the Ag NPs were observed to induce localized surface plasmons (LSP) resonances on the SiC substrate, which was expected to improve the internal quantum efficiency (IQE) of the emissions of the donor-acceptor pairs of the SiC substrate. Room-temperature measurements of photoluminescence (PL), transmittance and time-resolved photoluminescence (TRPL) were applied to characterize the LSP resonances. Through the finite-difference time-domain (FDTD) simulation of the LSP resonance of an Ag nanoparticle on the SiC substrate, it is predicted that when the diameter of the cross section on the xy plane of the Ag nanoparticle is greater than 225 nm, the LSP starts to enhance the PL intensity. With implementation of a 3rd order exponential decay fitting model to the TRPL results, it is found that the average minority carrier lifetime of the SiC substrate decreased.

scholarly journals Time Resolved Photoluminescence of Cubic Mg Doped GaN

1999 ◽  
Vol 572 ◽  
Author(s):  
R. Seitz ◽  
C. Gaspar ◽  
T. Monteiro ◽  
E. Pereira ◽  
B. Schoettker ◽  
...  
Keyword(s):  
Blue Emission ◽  
Spectral Shift ◽  
Excitation Density ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Deep Donor ◽  
Cubic Gan ◽  
Donor Acceptor ◽  
Time Resolved Photoluminescence ◽  
Mg Doped

ABSTRACTMg doped cubic GaN layers were studied by steady state and time resolved photoluminescence. The blue emission due to Mg doping can be decomposed in three bands. The decay curves and the spectral shift with time delays indicates donor-acceptor pair behaviour. This can be confirmed by excitation density dependent measurements. Furthermore temperature dependent analysis shows that the three emissions have one impurity in common. We propose that this is an acceptor level related to the Mg incorporation and the three deep donor levels are due to compensation effects.

Sign in / Sign up

Export Citation Format

Share Document