Influence of structural nonuniformity and nonradiative processes on the luminescence efficiency of InGaAsN quantum wells

2006 ◽  
Vol 88 (1) ◽  
pp. 011903 ◽  
Author(s):  
L. Geelhaar ◽  
M. Galluppi ◽  
G. Jaschke ◽  
R. Averbeck ◽  
H. Riechert ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Luminescence Efficiency ◽  
Structural Nonuniformity ◽  
Nonradiative Processes

Scale Effects on Exciton Localization and Nonradiative Processes in GaN/AlGaN Quantum Wells

2000 ◽  
Vol 180 (1) ◽  
pp. 127-132 ◽  
Author(s):  
M. Gallart ◽  
A. Morel ◽  
T. Taliercio ◽  
P. Lefebvre ◽  
B. Gil ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Scale Effects ◽  
Exciton Localization ◽  
Nonradiative Processes

High Luminescence Efficiency from GaAsN Layers Grown by MBE with RF Nitrogen Plasma Source

2001 ◽  
Vol 692 ◽  
Author(s):  
Victor M. Ustinov ◽  
Nikolai A. Cherkashin ◽  
Nikolai A. Bert ◽  
Andrei F. Tsatsul'nikov ◽  
Alexei R. Kovsh ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Plasma Source ◽  
Peak Position ◽  
Nitrogen Plasma ◽  
Rf Plasma ◽  
Photoluminescence Intensity ◽  
Temperature Growth ◽  
Luminescence Efficiency ◽  
Lower Temperature ◽  
Reference Layer

Abstract(In)GaAsN based heterostructures have been found to be promising candidates for the active region of 1.3 micron VCSELs. However, (In)GaAsN bulk layers and quantum wells usually demonstrate lower photoluminescence intensity than their nitrogen-free analogues. Defects associated with lower temperature growth and N-related defects due to plasma cell operation and possible nonuniform distribution of nitrogen enhance the non-radiative recombination in N-contained layers. We studied the photoluminescence intensity of GaAsN layers as a function of N content in MBE grown samples using rf-plasma source. Increasing the growth temperature to as high as 520 °C in combination with the increase in the growth rate allowed us to avoid any N-related defects up to 1.5% of nitrogen. Low-temperature-growth defects can be removed by post-growth annealing. We achieved the same radiative efficiency of GaAsN samples grown at 520°C with that of reference layer of GaAs grown at 600°C. Compositional fluctuations in GaAsN layers lead to characteristic S-shape of temperature dependence of photoluminescence peak position and this feature is the more pronounced the higher the amount of nitrogen in GaAsN. Annealing reduces compositional fluctuations in addition to the increase in the photoluminescence intensity. The results obtained are important for further improving the characteristics of InGaAsN lasers emitting at 1.3 micron.

scholarly journals Anomalous Temperature Dependence of Photoluminescence Caused by Non-Equilibrium Distributed Carriers in InGaN/(In)GaN Multiple Quantum Wells

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1023
Author(s):  
Yuhao Ben ◽  
Feng Liang ◽  
Degang Zhao ◽  
Xiaowei Wang ◽  
Jing Yang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Temperature Dependence ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Hydrogen Treatment ◽  
Key Factors ◽  
Anomalous Temperature ◽  
Luminescence Efficiency ◽  
Integrated Intensity ◽  
Non Equilibrium

An increase of integrated photoluminescence (PL) intensity has been observed in a GaN-based multiple quantum wells (MQWs) sample. The integrated intensity of TDPL spectra forms an anomalous variation: it decreases from 30 to 100 K, then increases abnormally from 100 to 140 K and decreases again when temperature is beyond 140 K. The increased intensity is attributed to the electrons and holes whose distribution are spatial non-equilibrium distributed participated in the radiative recombination process and the quantum barrier layers are demonstrated to be the source of non-equilibrium distributed carriers. The temperature dependence of this kind of spatial non-equilibrium carriers’ dynamics is very different from that of equilibrium carriers, resulting in the increased emission efficiency which only occurs from 100 to 140 K. Moreover, the luminescence efficiency of MQWs with non-equilibrium carriers is much higher than that without non-equilibrium carriers, indicating the high luminescence efficiency of GaN-based LEDs may be caused by the non-equilibrium distributed carriers. Furthermore, a comparison analysis of MQWs sample with and without hydrogen treatment further demonstrates that the better quantum well is one of the key factors of this anomalous phenomenon.

Short-period AlGaN based superlattices for deep UV light emitting diodes grown by gas source molecular beam epitaxy

2005 ◽  
Vol 892 ◽  
Author(s):  
Sergey Nikishin ◽  
Boris Borisov ◽  
Vladimir Kuryatkov ◽  
Mark Holtz ◽  
Henryk Temkin
Keyword(s):  
Quantum Wells ◽  
Room Temperature ◽  
Light Emission ◽  
Uv Light ◽  
Growth Mode ◽  
Light Emitting ◽  
Gas Source ◽  
Luminescence Efficiency ◽  
Short Period ◽  
Short Period Superlattices

AbstractWe report the results of two studies of the growth and physical properties of AlGaN-based short-period superlattices (SPSLs), each aimed at improving light emission. In the first experiment, we grow structures on bulk AlN substrates. We observe ∼ 3 times higher luminescence efficiency than identically grown structures on sapphire. In the second experiment, we grow structures on sapphire while controlling the growth mode. We observe a significant improvement in the room temperature cathodoluminescence efficiency (at least by factor of 10) of AlGaN quantum wells when the 3D growth mode is induced by reduced flux of ammonia over identically prepared structures grown in the 2D mode.

Room-Temperature Defect Tolerance of Shape Engineered Quantum Dot Structures

2003 ◽  
Vol 799 ◽  
Author(s):  
Matthew Lamberti ◽  
Alex Katsnelson ◽  
Michael Yakimov ◽  
Gabriel Agnello ◽  
Vadim Tokranov ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Wells ◽  
Room Temperature ◽  
Defect Density ◽  
Variable Temperature ◽  
High Energy ◽  
Superior Performance ◽  
Defect Tolerance ◽  
Area Of Interest ◽  
Luminescence Efficiency

ABSTRACTA quantum dot (QD) medium is expected to demonstrate superior performance in various devices when compared with quantum wells (QWs). One area of interest has been the improved defect tolerance of QD media, though it was demonstrated at low temperatures so far. In this study, the defect tolerance of shape-engineered QD structures is compared with that of a QW structure at temperatures up to 300 K. To create high defect densities both QD and QW structures were irradiated with high energy (1.5 MeV) protons (with doses up to 3×1014 cm-2). Then, the relative luminescence efficiency was measured by variable temperature photoluminescence. The shape-engineered QD structure withstood two orders of magnitude higher defect density than the QWs at room temperature. This improvement is correlated with the activation energy for thermal evaporation of 390 meV, acquired through a kinetic model.

Optical Properties of Heavily Doped n-type CdSe Quantum Dots for Intersubband Device Applications

2006 ◽  
Vol 959 ◽  
Author(s):  
Shengkun Zhang ◽  
Xuecong Zhou ◽  
Aidong Shen ◽  
Wubao Wang ◽  
Robert Alfano ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Wells ◽  
Ir Absorption ◽  
Cdse Quantum Dots ◽  
Nonradiative Recombination ◽  
Time Resolved ◽  
Luminescence Efficiency ◽  
Decay Times ◽  
Heavily Doped

ABSTRACTIn this research, interband and intersubband optical properties of heavily doped n-type CdSe quantum dots were investigated by temperature dependent photoluminescence (PL) spectroscopy, picosecond time-resolved PL spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Two doped and one undoped CdSe quantum dot samples with multiple QD layers were grown over ZnCdMgSe barrier layers on InP (001) substrate by molecular beam epitaxy. Heavy doping leads to decreasing of activation energy of nonradiative recombination centers, however, does not affect the luminescence efficiency of doped quantum wells. Time resolved PL experiments show that the PL decay times of the doped samples have weak dependence on well width and are much longer than that of the undoped sample. The two doped CdSe QD samples show strong Intersubband IR absorption that peaked at 2.54 μm, 2.69 μm and 3.51 μm. The ISB absorption is found to be strongly polarization dependent due to the large size of the QDs.

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