scholarly journals Direct modulation of electroluminescence from silicon nanocrystals beyond radiative recombination rates

2008 ◽  
Vol 92 (9) ◽  
pp. 091103 ◽  
Author(s):  
Josep Carreras ◽  
J. Arbiol ◽  
B. Garrido ◽  
C. Bonafos ◽  
J. Montserrat
Keyword(s):  
Silicon Nanocrystals ◽  
Radiative Recombination ◽  
Recombination Rates ◽  
Direct Modulation

Impact of Anchoring Monolayers on the Enhancement of Radiative Recombination in Light-Emitting Diodes Based on Silicon Nanocrystals

2018 ◽  
Vol 122 (11) ◽  
pp. 6422-6430 ◽  
Author(s):  
Batu Ghosh ◽  
Takumi Hamaoka ◽  
Yoshihiro Nemoto ◽  
Masaki Takeguchi ◽  
Naoto Shirahata
Keyword(s):  
Silicon Nanocrystals ◽  
Radiative Recombination ◽  
Light Emitting Diodes ◽  
Light Emitting

Absorption and Emission of Light in Quantum Structures

2020 ◽  
pp. 343-418
Author(s):  
Vurgaftman Igor
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Quantum Wires ◽  
Incident Light ◽  
Optical Gain ◽  
Two Dimensional ◽  
Intersubband Transitions ◽  
Recombination Rates ◽  
Zinc Blende ◽  
Two Dimensional Materials

This chapter shows how to calculate the absorption coefficient, optical gain, and radiative recombination rates in quantum wells and superlattices. A detailed treatment of both interband and intersubband transitions is presented, and their differences and similarities are considered in detail. The optical properties of wurtzite quantum wells and zinc-blende quantum wires and dots are also discussed. Finally, the interaction of excitonic transitions with incident light in quantum wells is considered as a model for other two-dimensional materials.

scholarly journals Temperature-Dependent Photoluminescence of Manganese Halide with Tetrahedron Structure in Anti-Perovskites

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3310
Author(s):  
Yijie Xia ◽  
Shuaishuai Du ◽  
Pengju Huang ◽  
Luchao Wu ◽  
Siyu Yan ◽  
...  
Keyword(s):  
Energy Level ◽  
Recombination Rate ◽  
Radiative Recombination ◽  
Room Temperature ◽  
Energy Levels ◽  
Radiative Recombination Rate ◽  
Temperature Dependent ◽  
Recombination Rates ◽  
Increasing Temperature ◽  
Temperature Dependent Photoluminescence

The temperature-dependent photoluminescence (PL) properties of an anti-perovskite [MnBr4]BrCs3 sample in the temperature range of 78–500 K are studied in the present work. This material exhibits unique performance which is different from a typical perovskite. Experiments showed that from room temperature to 78 K, the luminous intensity increased as the temperature decreased. From room temperature to 500 K, the photoluminescence intensity gradually decreased with increasing temperature. Experiments with varying temperatures repeatedly showed that the emission wavelength was very stable. Based on the above-mentioned phenomenon of the changing photoluminescence under different temperatures, the mechanism is deduced from the temperature-dependent characteristics of excitons, and the experimental results are explained on the basis of the types of excitons with different energy levels and different recombination rates involved in the steady-state PL process. The results show that in the measured temperature range of 78–500 K, the steady-state PL of [MnBr4]BrCs3 had three excitons with different energy levels and recombination rates participating. The involved excitons with the highest energy level not only had a high radiative recombination rate, but a high non-radiative recombination rate as well. The excitons at the second-highest energy level had a similar radiative recombination rate to the lowest energy level excitons and a had high non-radiative recombination rate. These excitons made the photoluminescence gradually decrease with increasing temperature. This may be the reason for this material’s high photoluminescence efficiency and low electroluminescence efficiency.

scholarly journals Emission Lines of CI and N II in Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 225-225
Author(s):  
V. Escalante
Keyword(s):  
Radiative Recombination ◽  
Transition Probabilities ◽  
Potential Method ◽  
Dielectronic Recombination ◽  
Model Potential ◽  
Emission Lines ◽  
Published Data ◽  
Recombination Rates ◽  
Doubly Excited ◽  
Ngc 7027

A model potential method (Caves and Dalgarno, 1972, J. Quant. Spect. Rad. Transf., 12, 1539) was used to calculate accurate non-hydrogenic radiative recombination rates and transition probabilities of singly excited states of CI and N II. The results can be used to determine the excitation mechanism of emission lines and to estimate N III concentrations in nebulae with CI and N II emission lines. In most nebulae, observed permitted lines of N II are produced by radiative recombination, but sometimes stronger recombination lines are missing in their spectra. The [CI] lines observed in NGC 7027 cannot be explained by simple radiative and dielectronic recombination. The low [CI] λλ9850 + 23/ λ8727 value may indicate that the emission is produced in high density (NeZ 105 cm−3) condensations where partial collisional deexcitation of metastable levels, takes place. N III concentrations were determined using published data of NGC 3242, NGC 3918, and NGC 6572. The procedure outlined by Wilkes et al. (1981, M.N.R.A.S., 197, 1) to determine N abundances from (N+ + N++)/He+ ratios does not always give consistent results with UV or [N II] data. The problem may be due to errors in the calculation of transition probabilities involving the doubly excited levels 2s2p33P0 and 3D0 of N II that affect the branching and effective recombination rate of the multiplet N II λ5680.

Carrier Dynamics in Poly(Octylthiophene) Gels

2000 ◽  
Vol 660 ◽  
Author(s):  
J-C Vial ◽  
B. Pépin-Donat ◽  
A. Viallat ◽  
P. Fedorko
Keyword(s):  
Decay Time ◽  
Radiative Recombination ◽  
Carrier Transport ◽  
Organic Dyes ◽  
Dilution Effect ◽  
Carrier Dynamics ◽  
Swelling Ratio ◽  
Recombination Rates ◽  
Photoluminescence Decay ◽  
Interchain Interactions

ABSTRACTCarrier dynamics properties in swollen poly(octylthiophene) gels are investigated via their radiative and non-radiative recombination rates (Wr and Wnr respectively) as a function of their swelling ratio (Q). Photoluminescence decay time (τ, in the picosecond range) and luminescence quantum efficiency (QE) are found to strongly increase with Q. This implies that Wr increases and Wnr decreases as Q increases; such a result cannot be understood if one accounts only for the well-known dilution effect observed for organic dyes. Our interpretation is that the enhanced carrier transport due to the increase of interchain interactions observed upon deswelling induces a separation of carriers. Then, these latter present an increased probability to find non-radiative traps. Variation of the conductivity versus Q in doped gels is also discussed.

Radiative Recombination Rates in GaN, InN, AlN and their Solid Solutions

1996 ◽  
Vol 423 ◽  
Author(s):  
A. V. Dmitriev ◽  
A. L. Oruzheinikov
Keyword(s):  
Solid Solutions ◽  
Radiative Recombination ◽  
Energy Gap ◽  
Wide Band ◽  
Linear Interpolation ◽  
Recombination Rates ◽  
Wide Band Gap ◽  
Wide Range ◽  
Conductivity Band ◽  
First Time

AbstractThe radiative recombination rates have been calculated for the first time in the wide band gap wurtzite semiconductors GaN, InN and AIN and their solid solutions GaxAl1−xN and InxAl1−xN on the base of existing data on the energy band structure and optical absorption in these materials. We calculated the interband matrix elements for the direct optical transitions between the conductivity band and the valence one using the experimental photon energy dependence of the absorption coefficient near the band edge. In our calculations we assumed that the material parameters of the solid solutions (the interband matrix element, carrier effective masses and so on) could be obtained by a linear interpolation between their values in the alloy components. The temperature dependence of the energy gap was taken in the form proposed by Varshni. The calculations of the radiative recombination rates were performed in the wide range of temperature and alloy compositions.

Measurement of nonradiative Auger and radiative recombination rates in strained‐layer quantum‐well systems

1993 ◽  
Vol 62 (2) ◽  
pp. 166-168 ◽  
Author(s):  
M. C. Wang ◽  
K. Kash ◽  
C. E. Zah ◽  
R. Bhat ◽  
S. L. Chuang
Keyword(s):  
Quantum Well ◽  
Radiative Recombination ◽  
Recombination Rates ◽  
Strained Layer

scholarly journals Tunable Luminescent A-SiNxOy Films with High Internal Quantum Efficiency and Fast Radiative Recombination Rates

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2494
Author(s):  
Pengzhan Zhang ◽  
Leng Zhang ◽  
Xuefeng Ge ◽  
Sake Wang
Keyword(s):  
Radiative Recombination ◽  
Light Emission ◽  
Internal Quantum Efficiency ◽  
Silicon Oxynitride ◽  
Quantum Yields ◽  
Planar Geometry ◽  
Defect States ◽  
Recombination Rates ◽  
Time Resolved ◽  
Level Model

In this work, we systematically investigated the Nx bonding defects that induced high photoluminescence internal quantum efficiencies (PL IQEs) and very fast radiative recombination processes in amorphous silicon oxynitride (a-SiNxOy) systems. The luminescent N‒Si‒O bonding-related defect states were checked for the XPS, EPR, and temperature-dependent steady-state PL (TD-SSPL) properties. The PL IQEs were calculated from PL quantum yields through the principle of planar geometry optics, and then confirmed by the TD-SSPL properties. The radiative recombination rates [kr(R)] were determined by combining the PL IQE values and ns-PL lifetimes obtained from time-resolved PL measurements. Both the PL IQE, exceeding 72%, and the fast kr(R) (~108 s−1) are proportional to the concentration of Nx defects, which can be explained by N‒Si‒O bonding states related to the quasi-three-level model, suggesting the possible realization of stimulated light emission in a-SiNxOy systems.

Preparation condition and recombination rates at radiative defects in a-Si:H

2014 ◽  
Vol 92 (7/8) ◽  
pp. 561-564
Author(s):  
Chisato Ogihara ◽  
Yuta Shintoku ◽  
Kei Yamaguchi ◽  
Kazuo Morigaki
Keyword(s):  
Recombination Rate ◽  
Radiative Recombination ◽  
Preparation Condition ◽  
Thermal Excitation ◽  
Nonradiative Recombination ◽  
Radiative Recombination Rate ◽  
Recombination Rates ◽  
Strong Electron ◽  
Temperature Variations ◽  
Preparation Conditions

Recombination rates at radiative defects in the hydrogenated amorphous silicon films prepared at various preparation conditions, estimated from intensities and characteristic lifetimes of defect photoluminescence, have been investigated. The temperature variations of the radiative recombination rate are discussed in terms of a model in which the increase of the radiative recombination rate is attributed to the thermal excitation of the holes from deep and strongly localised tail states to shallow and more extended tail states. The temperature variations of nonradiative recombination rate are discussed in terms of a theory for the case of strong electron–phonon coupling.

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