Broadband Chirped InAs Quantum-Dot Superluminescent Light-Emitting Diodes With In<sub>x</sub>Al<sub>1-x</sub>As Strain-Reducing Layers

In this paper, broadband InAs quantum-dot (QD) superluminescent light-emitting diodes (SLEDs) are grown by molecular beam epitaxy, fabricated, and then characterized. In order to achieve broadband and uniform emission spectra, the active regions contain a combination of chirped InAs QDs with differe...

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Bibliographic Details
Main Authors: Ruizhe Yao, Nicholas Weir, Chi-Sen Lee, Wei Guo
Format: Article
Language:English
Published: IEEE 2016-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/7486046/
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Summary:In this paper, broadband InAs quantum-dot (QD) superluminescent light-emitting diodes (SLEDs) are grown by molecular beam epitaxy, fabricated, and then characterized. In order to achieve broadband and uniform emission spectra, the active regions contain a combination of chirped InAs QDs with different In<sub>x</sub>Al<sub>1-x</sub>As strain-reducing layers (SRLs). It has been shown that the In<sub>x</sub>Al<sub>1-x</sub>As SRLs can effectively enlarge the QD emission energy separation between the ground and the excited states. In this paper, QDs with increased energy separation are utilized to enable a broadband QD ensemble by adding additional QD layers with the ground state emission wavelength tuned to fill the gap in emission. In addition, we employed a short postgrowth annealing process of 30 s to further even out the emission spectra. Characterizations of the emission spectra of the as-grown QDs and fabricated QD SLEDs are performed by room-temperature photoluminescence and electroluminescence under continuous-wave (c-w) operation, respectively. In the SLED devices, a broad and uniform spectrum with a linewidth of 100 nm at 3 dB is realized at an injection current level of 100 mA, and no significant spectrum dip is observed in the entire injection current window ranging from 50 <inline-formula> <tex-math notation="LaTeX">$\mu\text{A}$</tex-math></inline-formula> to 100 mA.
ISSN:1943-0655