We present the enhancement of wall-plug efficiency in vertical InGaN/GaN light-emitting diodes (V-LEDs) by improved current spreading with a novel Al2O3 current blocking layer (CBL). The Al2O3 CBL deposited by electron-beam evaporation shows high transmittance and good corrosion resistance to acidic solutions. V-LEDs with an Al2O3 CBL show similar light output power but lower forward voltage as compared to those with a SiO2 CBL deposited by plasma-enhanced chemical vapor deposition. As a result, the wall-plug efficiency of V-LEDs with an Al2O3 CBL at 500 mA was improved by 5% as compared to those with a SiO2 CBL, and by 19% as compared to those without a CBL.
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http://dx.doi.org/10.1364/OE.20.00A287 | DOI Listing |
Discov Nano
December 2024
Department of Photonics, National Yang Ming Chiao Tung University, Hsinchu, 30010, Taiwan, ROC.
This study fabricated 10 μm chip size μLEDs of blue-light GaN based epilayers structure with different mesa processes using dry etching and ion implantation technology. Two ion sources, As and Ar, were applied to implant into the LED structure to achieve material isolation and avoid defects on the mesa sidewall caused by the plasma process. Excellent turn-on behavior was obtained in both ion-implanted samples, which also exhibited lower leakage current compared to the sample fabricated by the dry etching process.
View Article and Find Full Text PDFBy employing a graded-interfaces model based on a generalized formalism for interface-roughness (IFR) scattering that was modified for mid-infrared emitting quantum cascade lasers (QCLs), we have accurately reproduced the electro-optical characteristics of published record-performance 4.9 µm- and 8.3 µm-emitting QCLs.
View Article and Find Full Text PDFWater Res X
December 2024
Centre for Water Resources Studies, Dalhousie University Halifax, NS, B3H 4R2, Canada.
UV light emitting diode (LED) disinfection technologies have advanced over the last decade and expanded the design space for applications in point of use, industrial, and now full-scale water treatment. This literature review examines the progression of UV LED technologies from 2007 to 2023 using key features such as total optical power, price, and wall-plug efficiency. The review found that optical power is increasing while the price per Watt is decreasing; however, the wall plug energy (WPE) is slowly improving over the last decade.
View Article and Find Full Text PDFMater Horiz
December 2024
School of Physics and Optoelectronic Engineering, Guangdong University of Technology, WaiHuan Xi Road, No. 100, Guangzhou 510006, China.
Cr-activated garnet phosphors with broadband near-infrared (NIR) emission have attracted considerable interest due to their high quantum efficiency (QE) and thermal stability for widespread advanced applications. Nevertheless, how to achieve energy-saving broadband NIR phosphors that possess anti-thermal quenching (anti-TQ) without compromising the high QE has yet to be fully addressed. Herein, we report on site reconstruction within the garnet lattice by strategically positioning Sc and Ga atoms into octahedral B sites with a mole ratio of 1 : 1 to produce GdScGaO.
View Article and Find Full Text PDFNanomaterials (Basel)
August 2024
Department of Physics, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea.
The efficiency of current GaN-based blue laser diodes (LDs) is limited by the high resistance of a thick p-AlGaN cladding layer. To reduce the operation voltage of InGaN blue LDs, we investigated optimum LD structures with an indium tin oxide (ITO) partial cladding layer using numerical simulations of LD device characteristics such as laser power, forward voltage, and wall-plug efficiency (WPE). The wall-plug efficiency of the optimized structure with the ITO layer was found to increase by more than 20% relative to the WPE of conventional LD structures.
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