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Qi Z.,Huazhong University of Science and Technology | Li S.,Huazhong University of Science and Technology | Li S.,Xiamen sanAn Optoelectronics Co. | Li S.,Tianjin Sanan Optoelectronics Co. | And 6 more authors.
Journal of Electronic Materials | Year: 2015

The influences of the different growth methods of GaAs cap layer on the self-assembled InAs quantum dots were investigated via photoluminescence and transmission electron microscopy. A two-step growth technique, consisting of a low temperature pulsed atomic layer epitaxy and a high temperature conventional continuous growth method, could improve the surface morphology and photoluminescence intensity due to the enhancement of Ga atomic mobility and the reduction in dislocation density. Furthermore, the photoluminescence peak shows a red shift instead of a blue shift due to the strain relaxation. © 2015 The Minerals, Metals & Materials Society

Tianjin Sanan Optoelectronics Co. | Date: 2015-06-10

A light-emitting diode includes at least an N-type layer, a light-emitting layer and a P-type layer, wherein the light-emitting layer forms a V-shaped indentation or pit during epitaxial process and the V pit is filled in with at least one type of metal nanoparticles to generate surface plasma coupling effect and to improve recombination probability of holes and electrons, thus improving internal quantum efficiency; further, a V pit is generated in the N-type layer during epitaxial process; surface plasma coupling effect is generated by filling metal nanoparticles in the V pit to increase light reflection, light extraction efficiency and external quantum efficiency, thereby improving light emitting efficiency of LED; and the V pit is formed directly by adjusting growth rate, thickness, temperature, pressure or doping during epitaxial process instead of etching, which causes no damage to the LED epitaxial layer, thus simplifying process and improving device stability.

Li S.,Xiamen sanAn Optoelectronics Co. | Li S.,Tianjin Sanan Optoelectronics Co. | Li S.,Huazhong University of Science and Technology | Bi J.,Xiamen sanAn Optoelectronics Co. | And 16 more authors.
Nanoscale Research Letters | Year: 2015

The InAs/GaAs quantum dots structure embedded in GaInP/Ga(In)As/Ge triple junction solar cell with and without Ga0.90In0.10As strain reducing layer was investigated. Conversion efficiency of 33.91% at 1,000 suns AM 1.5D with Ga0.90In0.10As strain reducing layer was demonstrated. A 1.19% improvement of the conversion efficiency was obtained via inserting the Ga0.90In0.10As strain reducing layer. The main contribution of this improvement was from the increase of the short-circuit current, which is caused by the reduction of the Shockley–Read–Hall recombination centers. Consequently, there was a decrease in open circuit voltage due to the lower thermal activation energy of confined carriers in Ga0.9In0.1As than GaAs and a reduction in the effective band gap of quantum dots. © 2015, Li et al.; licensee Springer.

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