Influence of substrate dislocation density and quantum well width on the quantum efficiency of violet-emitting GaInN/GaN light-emitting diodes

2009 ◽  
Vol 6 (S2) ◽  
pp. S833-S836 ◽  
Author(s):  
Thorsten Passow ◽  
Markus Maier ◽  
Michael Kunzer ◽  
Crenguta-Columbina Leancu ◽  
Shangjing Liu ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Quantum Well ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Quantum Well Width ◽  
Influence Of Substrate

scholarly journals Dimension control of in situ fabricated CsPbClBr2 nanocrystal films toward efficient blue light-emitting diodes

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chenhui Wang ◽  
Dengbao Han ◽  
Junhui Wang ◽  
Yingguo Yang ◽  
Xinyue Liu ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Blue Emission ◽  
Light Emitting ◽  
Mixed Ligands ◽  
Dimension Control ◽  
Nanocrystal Films ◽  
Width Distribution ◽  
Quantum Well Width

AbstractIn the field of perovskite light-emitting diodes (PeLEDs), the performance of blue emissive electroluminescence devices lags behind the other counterparts due to the lack of fabrication methodology. Herein, we demonstrate the in situ fabrication of CsPbClBr2 nanocrystal films by using mixed ligands of 2-phenylethanamine bromide (PEABr) and 3,3-diphenylpropylamine bromide (DPPABr). PEABr dominates the formation of quasi-two-dimensional perovskites with small-n domains, while DPPABr induces the formation of large-n domains. Strong blue emission at 470 nm with a photoluminescence quantum yield up to 60% was obtained by mixing the two ligands due to the formation of a narrower quantum-well width distribution. Based on such films, efficient blue PeLEDs with a maximum external quantum efficiency of 8.8% were achieved at 473 nm. Furthermore, we illustrate that the use of dual-ligand with respective tendency of forming small-n and large-n domains is a versatile strategy to achieve narrow quantum-well width distribution for photoluminescence enhancement.

(In)AlGaN deep ultraviolet light emitting diodes with optimized quantum well width

2010 ◽  
Vol 207 (9) ◽  
pp. 2198-2200 ◽  
Author(s):  
Tim Kolbe ◽  
Toni Sembdner ◽  
Arne Knauer ◽  
Viola Kueller ◽  
Hernan Rodriguez ◽  
...  
Keyword(s):  
Quantum Well ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Quantum Well Width ◽  
Deep Ultraviolet ◽  
Ultraviolet Light Emitting Diodes

Yellow-green emission for ETS-LEDs and lasers based on a strained–InGaP quantum well heterostructure grown on a transparent, compositionally graded AlInGaP buffer

2002 ◽  
Vol 744 ◽  
Author(s):  
Lisa McGill ◽  
Juwell Wu ◽  
Eugene Fitzgerald
Keyword(s):  
Dislocation Density ◽  
Quantum Well ◽  
Gallium Phosphide ◽  
Light Emitting Diodes ◽  
Green Emission ◽  
Threading Dislocation ◽  
Peak Wavelength ◽  
Device Structure ◽  
Light Emitting ◽  
Threading Dislocation Density

ABSTRACTEpitaxial-transparent-substrate light emitting diodes with a primary emission peak at 590nm and a secondary peak at 560nm have been fabricated in the indium aluminum gallium phosphide (InAlGaP) system. The active layer consists of an undoped, compressively strained indium gallium phosphide (InGaP) quantum well on a transparent In0.22(Al0.2Ga0.8)0.78P/ ∇x[1nx(Al0.2Ga0.8)1-xP] /GaP virtual substrate. Theoretical modeling of this structure predicts an accessible wavelength range of approximately 540nm to 590nm (green to amber). Emission with a peak wavelength of 570nm has been observed via cathodoluminescence studies of undoped structures with a quantum well composition of In0.35Ga0.65P. Light emitting diodes have been fabricated utilizing simple top and bottom contacts. The highest LED power of 0.18μW per facet at 20mA was observed for a quantum well composition of In0.32Ga0.68P and a bulk threading dislocation density on the order of 7×106 cm-2. The spectrum of this device was composed of two peaks: a weak peak at the predicted 560nm wavelength and a stronger peak at 590nm. Based upon superspots present in electron diffraction from the quantum well region, we believe that the observed spectrum is the result of emission from ordered and disordered domains in the active region. The same device structure grown with a bulk threading dislocation density on the order of 5×107 cm-2 exhibited an identical spectral shape with a reduced power of 0.08μW per facet at 20mA. For a quantum well composition of In0.37Ga0.63P and an overall threading dislocation density on the order of 5×107 cm-2, a single peak wavelength of 588nm with a power of 0.06μW per facet at 20mA was observed.

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