Temperature characteristics of GaN-based laser diodes are investigated. It is noted that the characteristic temperature of the threshold current (T) decreases with decreasing lasing wavelength for GaN-based LDs. The performance deteriorates seriously for UV LDs at high temperature. It is ascribed to the increase of carriers escaping from quantum wells due to the lower potential barrier height. In this Letter, AlGaN is used as the barrier layer in UV LDs instead of GaN to improve the temperature characteristic of the threshold current and slope efficiency by increasing the potential barrier height of quantum wells. Based on this structure, a high output power of 4.6 W is obtained at the injection current of 3.8 A; its lasing wavelength is 386.8 nm.
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http://dx.doi.org/10.1364/OL.515502 | DOI Listing |
Nature
January 2025
imec, Leuven, Belgium.
Silicon photonics is a rapidly developing technology that promises to revolutionize the way we communicate, compute and sense the world. However, the lack of highly scalable, native complementary metal-oxide-semiconductor (CMOS)-integrated light sources is one of the main factors hampering its widespread adoption. Despite considerable progress in hybrid and heterogeneous integration of III-V light sources on silicon, monolithic integration by direct epitaxy of III-V materials remains the pinnacle of cost-effective on-chip light sources.
View Article and Find Full Text PDFNano Lett
December 2024
Wyant College of Optical Sciences, University of Arizona, 1630 East University Boulevard, Tucson, Arizona 85721, United States.
Microscopic many-body models based on inputs from first-principles density functional theory are used to calculate the carrier losses due to free carrier Auger-Meitner recombination (AMR) processes in Mo- and W-based monolayer transition metal dichalcogenides as a function of the carrier density, temperature, and dielectric environment. Despite the exceptional strength of Coulomb interaction in the two-dimensional materials, the AMR losses are found to be similar in magnitude to those in conventional III-V-based quantum wells for the same wavelengths. Unlike the case in III-V materials, the losses show nontrivial density dependencies due to the fact that bandgap renormalizations on the order of hundreds of millielectronvolts can bring higher bands into or out of resonance with the optimal energy level for the AMR transition, approximately one bandgap from the lowest band.
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 PDFNanomaterials (Basel)
November 2024
Institute of Micro and Nano Electronics, Chavchavadze Ave. 13, Tbilisi 0179, Georgia.
Recently, geometry-induced quantum effects in a new quasi-1D system, or nanograting (NG) layers, were introduced and investigated. Dramatic changes in band structure and unconventional photoluminescence effects were found in silicon quantum wells with high-energy barriers. Nanograting metal-semiconductor junctions were fabricated and investigated.
View Article and Find Full Text PDFNanophotonics
April 2024
Department of Physics and Electronics, Osaka Metropolitan University, Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan.
Light-emitting diodes (LEDs) are widely used as next-generation light sources because of their various advantages. However, their luminous efficiency is remarkably low at the green-emission wavelength. The luminous efficiencies of InGaN/GaN quantum wells (QWs) significantly decrease with increasing indium content in the green wavelength region, mainly owing to the quantum-confined Stark effect (QCSE).
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