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AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) experience a notable reduction in efficiency within the 280-330 nm wavelength range, known as the "UVB gap". Given the extensive applications of UV LEDs in this wavelength range, it is imperative to bridge this efficiency gap. In this study, a strategy facilitated by the presence of residual Al adatoms is introduced to simultaneously improve the integration of Ga-adatoms and the migration of Al/Ga-adatoms during the growth of low-Al-composition AlGaN quantum wells (QWs) even at high temperatures comparable to those used for high-Al-composition AlGaN quantum barriers. This growth strategy enables the epitaxy of high-quality AlGaN QWs with a wide tunable emission wavelength range across the UVB gap. Utilizing this approach, high-efficiency UV LEDs that effectively bridge the UVB gap are developed. Furthermore, benefiting from this QWs growth configuration, these UV LEDs exhibit an exceptionally long L lifetime, marking a significant step forward in the growth technology of AlGaN QWs and expanding the application possibilities of UV LEDs.
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http://dx.doi.org/10.1002/adma.202501601 | DOI Listing |
Sci Rep
April 2025
Department of Information Engineering, University of Padova, Via Gradenigo 6/B, 35131, Padova, Italy.
We propose a detailed approach for modeling the C-V characteristic of complex heterostructure-based devices, investigating the case of UV-C LEDs. The study is based on combined experimental measurements and TCAD simulations, and explores: i) the impact of defects at critical interfaces on the apparent charge profile; ii) the dependence of the C-V characteristic on the efficiency of carrier injection toward the QWs; iii) the impact of a non-ideal partially-rectifying p-contact on the C-V curves. By accounting for these processes and non-idealities, we were able to achieve a good reproduction of the experimental C-V characteristic and of the corresponding apparent charge profile.
View Article and Find Full Text PDFAdv Mater
May 2025
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China.
AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) experience a notable reduction in efficiency within the 280-330 nm wavelength range, known as the "UVB gap". Given the extensive applications of UV LEDs in this wavelength range, it is imperative to bridge this efficiency gap. In this study, a strategy facilitated by the presence of residual Al adatoms is introduced to simultaneously improve the integration of Ga-adatoms and the migration of Al/Ga-adatoms during the growth of low-Al-composition AlGaN quantum wells (QWs) even at high temperatures comparable to those used for high-Al-composition AlGaN quantum barriers.
View Article and Find Full Text PDFPhys Rev E
November 2024
Institute of Physics, University of Opole, Oleska 48, 45-052 Opole, Poland.
We study the effects of disorder on the exciton spectra in quantum well (QW) semiconductor structures. We model the disorder by introducing the fractional Laplacian into the Schrödinger equations, which describe the exciton spectra of the above QW structures. We calculate the exciton binding energies in its ground state and a few low-lying excited states as a function of the GaAs QW size.
View Article and Find Full Text PDFNano Lett
August 2024
Laboratory of Advanced Semiconductors for Photonics and Electronics, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
In this study, we investigate the impact of two-dimensional MoS coating on the optical properties of surface GaN/AlGaN quantum wells (QWs). A strong enhancement in GaN QW light emission is observed with monolayer-MoS coating, yielding luminescence intensity comparable to that from a QW capped by an AlGaN barrier. Our results demonstrate that MoS, despite its quite different nature from III-nitride semiconductors, acts as an effective barrier for surface GaN QWs and suppresses spatially localized intrinsic surface states.
View Article and Find Full Text PDFLight Sci Appl
October 2022
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, 48109, USA.
Micro or submicron scale light-emitting diodes (µLEDs) have been extensively studied recently as the next-generation display technology. It is desired that µLEDs exhibit high stability and efficiency, submicron pixel size, and potential monolithic integration with Si-based complementary metal-oxide-semiconductor (CMOS) electronics. Achieving such µLEDs, however, has remained a daunting challenge.
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