Role of nonradiative recombination centers and extended defects in nonpolar GaN on light emission efficiency

2011 ◽  
Vol 98 (7) ◽  
pp. 072104 ◽  
Author(s):  
A. Y. Polyakov ◽  
N. B. Smirnov ◽  
A. V. Govorkov ◽  
H. Amano ◽  
S. J. Pearton ◽  
...  
1993 ◽  
Vol 63 (22) ◽  
pp. 3023-3025 ◽  
Author(s):  
S. Guha ◽  
J. M. DePuydt ◽  
J. Qiu ◽  
G. E. Hofler ◽  
M. A. Haase ◽  
...  

2020 ◽  
Vol 8 (26) ◽  
pp. 12964-12967
Author(s):  
Xie Zhang ◽  
Jimmy-Xuan Shen ◽  
Mark E. Turiansky ◽  
Chris G. Van de Walle

BiPb is not a recombination center in hybrid perovskites, but promotes the formation of the actual recombination centers—iodine interstitials.


1994 ◽  
Vol 351 ◽  
Author(s):  
Shinji Nozaki ◽  
S. Sato ◽  
H. Ono ◽  
H. Morisaki

ABSTRACTThe oxygen-containing silicon (Si) ultrafine particles have been deposited onto Si and SiO2 substrates by evaporation of Si powder in an oxygen-containing argon atmosphere. The asdeposited Si ultrafine particles exposed to the ultraviolet light emit blue light, which is strong enough to be seen with the naked eye. The blue light emission is associated with a broad photoluminescence (PL) peak at 2.7 eV, which is attributed to radiative recombination via a radiative recombination center. The proposed model with one radiative and two nonradiative recombination centers well explains the temperature-dependent PL peak intensity.


Author(s):  
David R. Veblen

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.


2021 ◽  
Vol 186 ◽  
pp. 109025
Author(s):  
João Humberto Dias Campos ◽  
Meiry Edivirges Alvarenga ◽  
Maykon Alves Lemes ◽  
José Antônio do Nascimento Neto ◽  
Freddy Fernandes Guimarães ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agata Bojarska-Cieślińska ◽  
Łucja Marona ◽  
Julita Smalc-Koziorowska ◽  
Szymon Grzanka ◽  
Jan Weyher ◽  
...  

AbstractIn this work we investigate the role of threading dislocations in nitride light emitters with different indium composition. We compare the properties of laser diodes grown on the low defect density GaN substrate with their counterparts grown on sapphire substrate in the same epitaxial process. All structures were produced by metalorganic vapour phase epitaxy and emit light in the range 383–477 nm. We observe that intensity of electroluminescence is strong in the whole spectral region for devices grown on GaN, but decreases rapidly for the devices on sapphire and emitting at wavelength shorter than 420 nm. We interpret this behaviour in terms of increasing importance of dislocation related nonradiative recombination for low indium content structures. Our studies show that edge dislocations are the main source of nonradiative recombination. We observe that long wavelength emitting structures are characterized by higher average light intensity in cathodoluminescence and better thermal stability. These findings indicate that diffusion path of carriers in these samples is shorter, limiting the amount of carriers reaching nonradiative recombination centers. According to TEM images only mixed dislocations open into the V-pits, usually above the multi quantum wells thus not influencing directly the emission.


2013 ◽  
Vol 20 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Gunasekar Naresh-Kumar ◽  
Jochen Bruckbauer ◽  
Paul R. Edwards ◽  
Simon Kraeusel ◽  
Ben Hourahine ◽  
...  

AbstractWe combine two scanning electron microscopy techniques to investigate the influence of dislocations on the light emission from nitride semiconductors. Combining electron channeling contrast imaging and cathodoluminescence imaging enables both the structural and luminescence properties of a sample to be investigated without structural damage to the sample. The electron channeling contrast image is very sensitive to distortions of the crystal lattice, resulting in individual threading dislocations appearing as spots with black–white contrast. Dislocations giving rise to nonradiative recombination are observed as black spots in the cathodoluminescence image. Comparison of the images from exactly the same micron-scale region of a sample demonstrates a one-to-one correlation between the presence of single threading dislocations and resolved dark spots in the cathodoluminescence image. In addition, we have also obtained an atomic force microscopy image from the same region of the sample, which confirms that both pure edge dislocations and those with a screw component (i.e., screw and mixed dislocations) act as nonradiative recombination centers for the Si-doped c-plane GaN thin film investigated.


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