Mechanisms of exciton photoluminescence quenching in the electric field of a standing surface acoustic wave

2019 ◽  
Vol 33 (06) ◽  
pp. 1950032
Author(s):  
D. V. Gulyaev ◽  
K. S. Zhuravlev
Keyword(s):  
Acoustic Wave ◽  
Electric Field ◽  
Quantum Wells ◽  
Surface Acoustic Wave ◽  
Impact Ionization ◽  
Interface Roughness ◽  
Nonradiative Recombination ◽  
Recombination Centers ◽  
Subsequent Capture ◽  
The Impact

Mechanisms of exciton photoluminescence (PL) quenching in the longitudinal electric field of a standing surface acoustic wave (SAW) have been studied by the example of type II GaAs/AlAs superlattices (SLs). Such SLs with a long lifetime of nonequilibrium carriers have allowed examining the influence of the SAW electric field on the excitonic PL both under the continuous and impulse laser excitations. It has been found that the mechanisms of the interaction of excitons and a SAW electric field depend upon the kinetic energy of excitons and carriers. As for hot excitons and carriers, the standing SAW electric field causes the impact ionization of excitons with a subsequent capture of free carriers at the nonradiative recombination centers, which results in a decrease in the steady-state exciton PL. As for cold excitons and carriers, the impact of excitons with the carriers accelerated by the SAW electric field results mainly in exciton delocalization from the levels of quantum wells formed due to interface roughness with a subsequent capture of excitons at the nonradiative recombination centers, which leads to the acceleration of the PL kinetics.

Nonradiative recombination centers in deep UV-wavelength AlGaN quantum wells detected by below-gap excitation light

2019 ◽  
Vol 58 (SC) ◽  
pp. SCCB37 ◽  
Author(s):  
M. Ismail Hossain ◽  
Yuri Itokazu ◽  
Shunsuke Kuwaba ◽  
Norihiko Kamata ◽  
Noritoshi Maeda ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Nonradiative Recombination ◽  
Excitation Light ◽  
Recombination Centers ◽  
Deep Uv

scholarly journals Photoluminescence Characterization of Nonradiative Recombination Centers in Light Emitting Materials by Utilizing Below-Gap Excitation: A Mini Review of Two-Wavelength Excited Photoluminescence

2015 ◽  
Vol 43 ◽  
pp. 1-9
Author(s):  
Norihiko Kamata ◽  
Abu Zafor Md. Touhidul Islam
Keyword(s):  
Quantum Wells ◽  
Electrical Contact ◽  
Intensity Change ◽  
Nonradiative Recombination ◽  
Excitation Light ◽  
Light Emitting ◽  
Recombination Centers ◽  
Pl Intensity ◽  
Trap Filling

We have developed an optical method of detecting and characterizing nonradiative recombination (NRR) centers without electrical contact. The method combines a below-gap excitation (BGE) light with a conventional above-gap excitation light in photoluminescence (PL) measurement, and discriminates the PL intensity change due to switching on and off the BGE. A quantitative analysis of the detected NRR centers became possible by utilizing the saturating tendency of the PL intensity change with increasing the BGE density due to trap filling effect. Some experimental results of AlGaAs, InGaN, and AlGaN quantum wells were shown to allocate the development and present status as well as to exemplify their interpretations.

Optical detection of nonradiative recombination centers in AlGaN quantum wells for deep UV region

2014 ◽  
Vol 11 (3-4) ◽  
pp. 832-835 ◽  
Author(s):  
A. Z. M. Touhidul Islam ◽  
N. Murakoshi ◽  
T. Fukuda ◽  
H. Hirayama ◽  
N. Kamata
Keyword(s):  
Quantum Wells ◽  
Optical Detection ◽  
Nonradiative Recombination ◽  
Recombination Centers ◽  
Deep Uv

Ion-Induced Anomalous Charge Collection Mechanisms in SiC Schottky Barrier Diodes

2015 ◽  
Vol 821-823 ◽  
pp. 575-578 ◽  
Author(s):  
Takahiro Makino ◽  
Manato Deki ◽  
Shinobu Onoda ◽  
Norihiro Hoshino ◽  
Hidekazu Tsuchida ◽  
...  
Keyword(s):  
Electric Field ◽  
Schottky Barrier ◽  
Layer Thickness ◽  
Epitaxial Layer ◽  
Impact Ionization ◽  
Heavy Ion ◽  
Charge Collection ◽  
Static Electric Field ◽  
The Impact ◽  
Lower Electric Field

The charge induced in SiC-SBDs with different epi-layer thicknesses by ion incidence was measured to understand the mechanism of heavy-ion-induced anomalous charge collection in SiC-SBDs. SiC SBD of which epitaxial-layer thicknesses is close to ion range show larger anomalous charge collection than SBD with thicker epi-layer although the former one has lower electric field than the later one. The gains of collected charge from the SBDs suggest that the impact ionization under 0.16 - 0.18 MV/cm of the static electric field in depletion layer is not dominant mechanisms for the anomalous charge collection. It is suggested that the epitaxial-layer thickness and ion-induced transient high electric field are key to understand the anomalous charge collection mechanisms in SBDs.

Photoluminescence intensity of GaN films with widely varying dislocation density

2003 ◽  
Vol 18 (5) ◽  
pp. 1247-1250 ◽  
Author(s):  
Yue Jun Sun ◽  
Oliver Brandt ◽  
Klaus H. Ploog
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Geometrical Model ◽  
Nonradiative Recombination ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Recombination Centers ◽  
The Impact

We investigated the impact of the presence of dislocations on room-temperature photoluminescence intensity in GaN films grown by molecular beam epitaxy. To determine both screw and edge dislocation densities, we employed x-ray diffraction in conjunction with a geometrical model, which relate the width of the respective reflections to the polar and azimuthal orientational spread. There is no direct dependence of the emission efficiency on the density of either type of dislocation in the samples under investigation. We conclude that dislocations are not the dominant nonradiative recombination centers for GaN grown by molecular beam epitaxy.

scholarly journals Radiative Lifetime of Excitons in GaInN/GaN Quantum Wells

1996 ◽  
Vol 1 ◽  
Author(s):  
Jin Seo Im ◽  
Volker Härle ◽  
Ferdinand Scholz ◽  
Andreas Hangleiter
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Decay Time ◽  
Elevated Temperatures ◽  
Radiative Lifetime ◽  
Thermal Dissociation ◽  
Interface Roughness ◽  
Nonradiative Recombination ◽  
Quantum Well Structures ◽  
Decay Times

We have studied GaInN/GaN quantum well structures grown by LP-MOVPE by picosecond time-resolved photoluminescence spectroscopy. For the quantum wells we find rather long PL decay times of up to 600 ps at low temperature. At temperatures higher than about 100 K, the decay time decreases rapidly, reaching about 75 ps at room temperature. From measurements of the integrated PL intensity, we conclude that this decrease of the decay time is due to nonradiative recombination processes. By combining our data for the lifetime and the intensity, we derive the radiative lifetime, which is constant at low temperature and increases at elevated temperatures. We explain this behavior on the basis of the interface roughness at low temperature and thermal dissociation of excitons at higher temperatures.

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