Article
Optics
Katarzyna Pieniak, Witold Trzeciakowski, Grzegorz Muziol, Anna Kafar, Marcin Siekacz, Czeslaw Skierbiszewski, Tadeusz Suski
Summary: The study examined electroluminescence from In0.17Ga0.83N/GaN quantum wells of LEDs and LDs, finding a transition from ground-states recombination to excited states recombination with increasing QW width. The effect is accompanied by partial or complete screening of the built-in electric field with increasing driving current, which was studied using a high pressure method. Investigations were supported by simulations of the variation with driving current of electron and hole wavefunctions overlap affecting the recombination channel and built-in electric field.
Article
Nanoscience & Nanotechnology
K. Khan, S. Diez, Kai Sun, C. Wurm, U. K. Mishra, E. Ahmadi
Summary: This study reports the observation of self-assembled InGaN/(In)GaN superlattice structure in InGaN film grown on N-polar GaN substrate, with varying In content in each layer depending on growth temperature. By increasing the substrate temperature, a periodic structure was achieved, offering a new pathway for designing and fabricating electronic and optoelectronic devices with enhanced performance.
Article
Chemistry, Physical
Yuelan Li, Tianman Wang, Lin Wang, Daishu Deng, Jun Lei, Jiawei Qiang, Sen Liao, Yingheng Huang
Summary: The Mn4+-equivalently doped fluoride K2TiF6:Mn4+ (KTF:Mn4+) exhibits red emission with high color purity. By employing the NH4+ doping strategy, the luminescence of KTF:Mn4+ is significantly enhanced by 2.27 times in intensity and slightly improved in decay time. This enhancement is attributed to lattice distortion caused by NH4+ substitution, leading to improved stability of Mn4+ and reduced defects and impurities.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Do-Yeong Shin, Taehwan Kim, Ozgun Akyuz, Hilmi Volkan Demir, In-Hwan Lee
Summary: This study presents an improved efficiency design for white LEDs by integrating blue nanorod LEDs with green and red-emitting perovskite nanocrystal films. The design utilizes the localized surface plasmon effect of Ag@SiO2 nanoparticles to enhance the photoluminescence intensity of blue LEDs, while the high-power blue LED backlight improves the perovskite photoluminescence intensity. The resulting white LED with Ag@SiO2 nanoparticle-embedded nanorods demonstrates a 62% increase in photoluminescence intensity compared to planar white LEDs.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Nanoscience & Nanotechnology
Xuan Li, Jianping Liu, Aiqin Tian, Lei Hu, Xiaoyu Ren, Siyi Huang, Wei Zhou, Dan Wang, Deyao Li, Hui Yang
Summary: The effects of AlGaN interlayer on the structural and optical properties of InGaN green laser diodes (LDs) grown on c-plane GaN substrate were investigated using scanning transmission electron microscope and temperature-dependent photoluminescence. The AlGaN interlayer improves the sharpness of InGaN quantum well interfaces, but does not suppress the localization effect. It also leads to an increase in nonradiative recombination centers in the active region of green InGaN LD.
Article
Optics
Shengjun Zhou, Zehong Wan, Yu Lei, Bin Tang, Guoyi Tao, Peng Du, Xiaoyu Zhao
Summary: This study proposes the use of InGaN quantum wells with gradually varying indium content to enhance the performance of GaN-based green LEDs. Experimental results demonstrate that green LEDs with gradually varying indium content exhibit higher light output power and lower efficiency droop.
Article
Physics, Applied
Shixiong Zhang, Ning Tang, Zhenhao Sun, Guoping Li, Teng Fan, Lei Fu, Yunfan Zhang, Jiayang Jiang, Peng Jin, Weikun Ge, Bo Shen
Summary: The correlation between spin-polarized carrier transfer and spin relaxation processes of a 2DEG in an InGaN/GaN quantum well is investigated. It is found that by tailoring the spin-orbit couplings, the spin relaxation time can be enhanced, which is significant for the development of GaN-based spintronic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Optics
Ryan Anderson, Haojun Zhang, Emily Trageser, Nathan Palmquist, Matt Wong, Shuji Nakamura, Steven DenBaars
Summary: Green GaN lasers with emission wavelength at 510 nm were successfully fabricated using novel nano-porous GaN cladding under pulsed electrical injection. The low slope efficiency and high threshold current density were attributed to poor injection efficiency and high loss. The independent characterization methods of variable stripe length and segmented contacts were used to analyze the laser performance, and it was found that continuous wave operation resulted in narrowed spectra and enhanced spontaneous emission.
Article
Physics, Applied
Abu Bashar Mohammad Hamidul Islam, Tae Kyoung Kim, Dong-Soo Shin, Jong-In Shim, Joon Seop Kwak
Summary: This study investigates the effect of current stress on InGaN/GaN multiple-quantum-well flip-chip blue micro light-emitting diodes (mu-LEDs) and reveals the mechanisms of defect aggregation and generation that cause changes in the optoelectronic performance of the devices. The aging test shows that the improvement in crystal quality due to defect aggregation initially enhances the light output power and external quantum efficiency (EQE), but the generation of sidewall point defects eventually leads to performance degradation. The findings highlight the importance of both defect aggregation and generation in understanding the degradation mechanisms of mu-LEDs.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Li Liu, Qingqing Feng, Yu Zhang, Xiaolu Zhu, Lanli Chen, Zhihua Xiong
Summary: Improving the luminescence efficiency of long wavelength InGaN-based LEDs is a challenging task, and strain-induced piezoelectric effect has been shown to be an effective measure. Reduction of valence band offset at InGaN/GaN heterointerfaces significantly improves hole injection. Tensile strain in the GaN film on a silicon substrate increases the overlap of electron and hole wave functions, leading to enhanced efficiency. Control of the strain-induced piezoelectric polarisation of the InGaN quantum well layer further improves the internal quantum efficiency.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Optics
Himanshu Karan, Abhijit Biswas
Summary: This study reports the optical performance of four InGaN/GaN multiple quantum well (MQW) blue LEDs with different bottom base widths, where the introduction of trapezoidal QW structure aids in reducing the piezoelectric polarization field, promoting carrier distribution uniformity, and increasing radiative recombination rate, with LED C showing the best performance.
Article
Optics
Zhe Zhuang, Daisuke Iida, Martin Velazquez-Rizo, Kazuhiro Ohkawa
Summary: The study introduced a method for fabricating ultra-small InGaN μLEDs, successfully realizing different shapes of green μLEDs. It was found that as the size of the μLED decreases, the series resistance and turn-on voltage increase, while the light output power density and external quantum efficiency also improve.
Article
Physics, Applied
Nicola Roccato, Francesco Piva, Carlo De Santi, Matteo Buffolo, Camille Haller, Jean-Francois Carlin, Nicolas Grandjean, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: The study found that the indium content in InGaN light-emitting diodes has a significant impact on defect density and degradation rate. Results indicate the important role of indium in favoring the incorporation of point defects.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Liwen Cheng, Xingyu Lin, Zhenwei Li, Da Yang, Jiayi Zhang, Jundi Wang, Jiarong Zhang, Yuru Jiang
Summary: InGaN LEDs with IGIT barriers have higher light output power, lower turn-on voltage, and less efficiency droop compared to LEDs with conventional GaN and InGaN barriers. These improvements are a result of the appropriately designed energy band diagram, which enhances hole injection efficiency and electron confinement.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Applied
Shaobo Yang, Shung-Hsiang Wu, Yu-Sheng Lin, Chun-Jui Chu, C. C. Yang
Summary: Although surface plasmon coupling is widely used to enhance the emission efficiency of an InGaN/GaN quantum well structure, the interplay between carrier transport behavior and SP coupling, which is a crucial mechanism controlling SP-coupling induced emission enhancement, remains unexplored.
JOURNAL OF APPLIED PHYSICS
(2023)
