Article
Physics, Applied
Simran Arora, Subhabrata Dhar
Summary: The electroluminescence properties of n(+)-ZnO/p-GaN pn(+)-heterojunctions grown epitaxially have been investigated as a function of applied bias and temperature. The study reveals the presence of indirect interfacial excitons at lower temperatures. The electroluminescence feature associated with these excitons is redshifted with increasing forward bias. The formation of these excitons becomes unsustainable when the applied bias or temperature exceeds a threshold due to leakage and thermal escape of charges.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Andreas Liudi Mulyo, Anjan Mukherjee, Ida Marie Hoiaas, Lyubomir Ahtapodov, Tron Arne Nilsen, Havard Hem Toftevaag, Per Erik Vullum, Katsumi Kishino, Helge Weman, Bjorn-Ove Fimland
Summary: This study successfully demonstrates the fabrication of flip-chip ultraviolet light-emitting diodes based on self-assembled GaN/AlGaN nanocolumns, using single-layer graphene as both a growth substrate and a transparent conducting electrode. The high crystalline quality of the nanocolumns and the presence of intrinsic GaN quantum disk are confirmed through detailed electron microscopy characterization. The optical emission characteristics reveal the absence of defect-related yellow emission and the presence of blue-shifted emission, attributed to quantum confinement and strain effects.
ACS APPLIED NANO MATERIALS
(2021)
Article
Optics
Shengjun Zhou, Zhefu Liao, Ke Sun, Ziqi Zhang, Yinzuo Qian, Pengfei Liu, Peng Du, Jingjing Jiang, Zhenxing Lv, Shengli Qi
Summary: This study develops ultrathin tunnel junction (UTJ) deep-UV light-emitting diodes (LEDs) with a low operating voltage of 5.7 V. The formation of Ohmic contact between high-work-function Ni/Au and Mg-Si co-doped n(+)- Al0.45Ga0.55N layer in UTJ is discovered. A high-efficiency sterilization deep-UV light source integrated with 120 UTJ deep-UV LED chips is developed.
LASER & PHOTONICS REVIEWS
(2023)
Article
Nanoscience & Nanotechnology
Ziquan Guo, Zhihui Li, Shouqiang Lai, Xiaoyang Hou, Xiaotong Fan, Chenming Zhong, Yue Lin, Guolong Chen, Guoheng Qin, Tao Gao, Nuoyi Fu, Yuan Shi, Xinqin Liao, Yi Lin, Yijun Lu, Weijie Guo, Zhong Chen
Summary: The temperature-dependent external quantum efficiency (EQE) droop of AlGaN-based UVC-LEDs with different Al contents at wavelengths of 265 nm, 275 nm, 280 nm, and 285 nm was comprehensively investigated. The recombination mechanisms in these UVC-LED samples were analyzed using the modified ABC model, revealing that the contribution of Shockley-Read-Hall recombination exceeds those of Auger recombination and carrier leakage at low electrical-current levels. At high electrical-current levels, Auger recombination and carrier leakage jointly dominate the EQE droop phenomenon. Experimental investigation of the inactivation efficiencies of various UVC light sources against Escherichia coli provides a technical reference for combating COVID-19.
Article
Materials Science, Multidisciplinary
Yong-Ho Ra, Cheul-Ro Lee
Summary: A new approach to reduce the size of photonic device chips is reported, utilizing a monolithic light reflector-nanowire LED system. Vertical cavity nanowire structure for surface-lighting emission is developed using selective area epitaxy, with the light reflection provided by Al metal reflector deposited by MBE technique. The approach shows significantly improved light efficiency at specific spectral wavelength, promising a new route for next-generation photonic and electronic devices.
ADVANCED MATERIALS TECHNOLOGIES
(2021)
Article
Chemistry, Multidisciplinary
Xiangyu Fu, Yash Mehta, Yi-An Chen, Lei Lei, Liping Zhu, Nilesh Barange, Qi Dong, Shichen Yin, Juliana Mendes, Siliang He, Renuka Gogusetti, Chih-Hao Chang, Franky So
Summary: The study demonstrates highly directional and polarized light emission from LEDs by selectively diffracting the TE waveguide mode, showing potential for more efficient photonic applications.
ADVANCED MATERIALS
(2021)
Article
Optics
Jinlong Piao, Junhua Wu, Ziqi Ye, Hao Zhang, Jinjia Li, Pengzhan Liu, Hao Wang, Ziping Cao, Yongjin Wang
Summary: In this study, a monolithic integration of a metal oxide semiconductor field effect phototransistor and a light-emitting diode on a GaN-on-Si LED epitaxial wafer was achieved. The integrated device showed promising performance as a UV detector and had potential applications in visible light communication.
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
Chemistry, Physical
Meditha Hudandini, Nurdiana Ratna Puri, Sugeng Winardi, Widiyastuti Widiyastuti, Manabu Shimada, Kusdianto Kusdianto
Summary: The treatment of wastewater from the textile industry is an important environmental issue, and photodegradation is considered a promising method for its mitigation. This study demonstrates that the loading of Ag onto ZnO enhances its catalytic activity and achieves optimal photodegradation results at a carrier gas ratio of 0:1.
Article
Physics, Applied
Tian-Run Zhang, Ya-Nan Wang, Yue-Feng Liu, Jing Feng
Summary: A transparent ultrathin Ag nanomesh electrode was fabricated using nanosphere lithography and a dielectric wetting layer. The nanomesh electrode exhibited higher figure of merit and improved optical and electrical performance compared to traditional ultrathin film Ag electrodes.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Ning Wang, Peng Wang, Fengzhi Wang, Haiping He, Jinyun Huang, Xinhua Pan, Guangming Zhu, Jiangbo Wang, Zhizhen Ye
Summary: This study investigates the growth of ZnO film on a graphene-buffered sapphire substrate using plasma-assisted molecular beam epitaxy (PAMBE). The results show that the crystal quality of ZnO film can be improved by buffering it with double-layer graphene (DLG), leading to the formation of symmetric pits on the film surface. The findings have implications for the development of simplified growth technology for ZnO-based films and devices.
APPLIED SURFACE SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Seung-Jae Lee, Seong Ran Jeon, Sung Hoon Jung, Young-Jun Choi, Hae-Gon Oh, Hae-Yong Lee, Min-Ki Kwon, Soon-Ku Hong
Summary: The characteristics of AlN epilayers grown directly on hole-type patterned sapphire substrate (HPSS) by hydride vapor-phase epitaxy (HVPE) are reported. The threading dislocation densities (TDDs) of AlN films grown simultaneously on HPSS and flat sapphire substrate (FSS) are analyzed by transmission electron microscopy. The results show that the TDD of AlN grown on HPSS is significantly lower than that on FSS.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Zinan Chen, Zhiyuan Qin, Sikai Su, Shuming Chen
Summary: The study reveals that the presence of H2O and O-2 affects the performance of Mg-doped zinc oxide (ZnMgO) and ZnMgO-based inverted quantum-dot light-emitting diodes (QLEDs). Exposure to ultraviolet (UV) irradiation can reduce the impact of O-2 on ZnMgO and increase the driving current.
Article
Optics
Yu-Hsuan Hsu, Kang-Wei Peng, Yi-Hsin Lin, Ming-Chun Tseng, Su-Hui Lin, Meng-Chun Shen, Ting-Zhu Wu, Zhong Chen, Ray-Hua Horng
Summary: This study fabricated high-voltage, low-current DUV-LEDs with better current spreading and enhanced reflective mirror effect, resulting in higher power output and efficiency compared to traditional devices. It has potential applications in high-voltage circuits to eliminate extra power consumption.
Article
Chemistry, Physical
Islam Mohammad Shafiqul, Toshiyuki Yoshida, Yasuhisa Fujita
Summary: Heterojunction light-emitting diodes (LEDs) based on p-type ZnO and n-type ZnMgO nanoparticles have been successfully fabricated. The experimental results show that the LEDs with the p-ZnO/n-ZnMgO/GZO structure exhibit better I-V characteristics and lower leakage current compared to the p-ZnO/GZO LEDs, and the emission intensity is improved by adding the ZnMgO NP layer.
