Carrier dynamics at trench defects in InGaN/GaN quantum wells revealed by time-resolved cathodoluminescence

Nanoscale ◽  
2021 ◽  
Author(s):  
Gunnar Kusch ◽  
Ella J Comish ◽  
Kagiso Loeto ◽  
Simon Hammersley ◽  
Menno Kappers ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Spectral Resolution ◽  
Semiconductor Nanostructures ◽  
Carrier Dynamics ◽  
Time Resolved

Time-resolved cathodoluminescence offers new possibilities for the study of semiconductor nanostructures – including defects. The versatile combination of time, spatial, and spectral resolution of the technique can provide new insights...

Spatially and Time-Resolved Carrier Dynamics in Core–Shell InGaN/GaN Multiple-Quantum Wells on GaN Wire

Nano Letters ◽  
2021 ◽  
Author(s):  
Jaime Segura-Ruiz ◽  
Damien Salomon ◽  
Andrei Rogalev ◽  
Joël Eymery ◽  
Benito Alén ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Carrier Dynamics ◽  
Multiple Quantum Wells ◽  
Core Shell ◽  
Multiple Quantum ◽  
Time Resolved

OPTICAL PROPERTIES AND CARRIER DYNAMICS IN ASYMMETRIC COUPLED InGaN MULTIPLE QUANTUM WELLS

2013 ◽  
Vol 06 (02) ◽  
pp. 1350021 ◽  
Author(s):  
GUO-EN WENG ◽  
BAO-PING ZHANG ◽  
MING-MING LIANG ◽  
XUE-QIN LV ◽  
JIANG-YONG ZHANG ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Energy Levels ◽  
Excitation Power ◽  
Equation Model ◽  
Carrier Dynamics ◽  
Multiple Quantum ◽  
Carrier Distribution ◽  
Time Resolved ◽  
Coupled Quantum Wells

Optical properties and carrier dynamics of InGaN/GaN asymmetric coupled quantum wells (ACQWs) are studied by excitation-power-dependent photoluminescence (PL), photoreflectance (PR) and time-resolved PL (TRPL) experiments. Under weak excitations, only the emission from the widest well is observed due to the tunneling from narrower to wider wells. Under strong excitations, the carrier distribution becomes more uniform and an enhanced emission from the mid well (2.5 nm well) is observed. Dependence of the PL intensity on excitation power is well explained by a rate equation model. The energy levels in the ACQW structure are clearly revealed by PR measurements and are in good agreement with calculations. Our results indicate that the enhanced emission from the mid well is ascribed to "reverse tunneling" from 3.0 to 2.5 nm well, which is confirmed by TRPL experiments.

Time Resolved Studies of Proton Irradiated Quantum Dots

2002 ◽  
Vol 722 ◽  
Author(s):  
Saulius Marcinkevičius ◽  
Rosa Leon ◽  
Charlene Lobo ◽  
Brian Magness ◽  
William Taylor
Keyword(s):  
Quantum Dots ◽  
Quantum Wells ◽  
Proton Irradiation ◽  
Three Dimensional ◽  
Carrier Dynamics ◽  
Time Resolved ◽  
Carrier Lifetimes ◽  
Dot Density ◽  
Gaas Quantum Dot ◽  
Time Resolved Photoluminescence

AbstractThe effects of proton irradiation on carrier dynamics were measured by time-resolved photoluminescence on InGaAs/GaAs quantum dot structures with different dot density and substrate orientation, as well as on InAlAs/AlGaAs quantum dots. Results were compared to irradiation effects on carrier dynamics in thin InGaAs quantum wells. We find that carrier lifetimes in QDs are much less affected by proton irradiation than in quantum wells, which can be attributed to the three-dimensional carrier confinement in quantum dots.

scholarly journals Effects of Crystal Morphology on the Hot-Carrier Dynamics in Mixed-Cation Hybrid Lead Halide Perovskites

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 708
Author(s):  
Daniele Catone ◽  
Giuseppe Ammirati ◽  
Patrick O’Keeffe ◽  
Faustino Martelli ◽  
Lorenzo Di Mario ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Carrier Dynamics ◽  
Large Area ◽  
Photovoltaic Properties ◽  
Time Resolved ◽  
Hot Carrier ◽  
Mixed Cation ◽  
Small Crystals ◽  
Characterization Of Materials ◽  
Lead Halide

Ultrafast pump-probe spectroscopies have proved to be an important tool for the investigation of charge carriers dynamics in perovskite materials providing crucial information on the dynamics of the excited carriers, and fundamental in the development of new devices with tailored photovoltaic properties. Fast transient absorbance spectroscopy on mixed-cation hybrid lead halide perovskite samples was used to investigate how the dimensions and the morphology of the perovskite crystals embedded in the capping (large crystals) and mesoporous (small crystals) layers affect the hot-carrier dynamics in the first hundreds of femtoseconds as a function of the excitation energy. The comparative study between samples with perovskite deposited on substrates with and without the mesoporous layer has shown how the small crystals preserve the temperature of the carriers for a longer period after the excitation than the large crystals. This study showed how the high sensitivity of the time-resolved spectroscopies in discriminating the transient response due to the different morphology of the crystals embedded in the layers of the same sample can be applied in the general characterization of materials to be used in solar cell devices and large area modules, providing further and valuable information for the optimization and enhancement of stability and efficiency in the power conversion of new perovskite-based devices.

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