Results 171 to 180 of about 2,177,698 (204)

Improve the Current Spreading for DUV LEDs

2019
After the crystalline quality for Al-rich AlGaN layer is significantly improved, it is then the time to design novel DUV LED structures. DUV LEDs are driven electrically which get carrier transport and current injection involved. One of the challenges is the current crowding effect, which easily occurs in the DUV LEDs.
Zi-Hui Zhang, Chunshuang Chu, Kangkai Tian, Yonghui Zhang   +3 more
openaire   +1 more source

Enhance the Electron Injection Efficiency for DUV LEDs

2019
The unbalanced carrier injection for DUV LEDs illustrates that the electron tends to overflow from the active region. The underly mechanism arises from three aspects: (1) electrons cannot be consumed by forming electron-hole pairs and recombine radiatively in the active region, which is due to the insufficient hole injection, (2) the electron have ...
Zi-Hui Zhang, Chunshuang Chu, Kangkai Tian, Yonghui Zhang   +3 more
openaire   +1 more source

Low parasitic carrier reservoir of AlGaN-based DUV-LED via controlled-polarization step-graded superlattice electron blocking layer for high luminescence lighting [PDF]

Physica Scripta
Achieving high luminescence intensity of deep-ultraviolet light-emitting diode (DUV-LED) is generally performed through the implementation of electron blocking layer (EBL) on the chip’s epilayers.
Hairol Aman, Mohammad Amirul, Ahmad Noorden, Ahmad Fakhrurrazi, Abdul Kadir@Jaafar, Muhammad Zamzuri, Daud, Suzairi   +3 more
exaly   +2 more sources

Degradation processes of 280 nm high power DUV LEDs: impact on parasitic luminescence [PDF]

Japanese Journal of Applied Physics, 2019
Abstract With this work we report on characterization and reliability analysis of 280 nm high power commercial LEDs emitting 18 mW at 200 mA, with a peak wavelength of 280 nm. Spectral characterization reports the presence of a main emission peak and a sideband peak separated by 0.8 eV. DLTS analysis has also been
Trivellin N., Monti D., Piva F., Buffolo M., De Santi C., Zanoni E., Meneghesso G., Meneghini M.   +7 more
openaire   +1 more source

Improve the Hole Injection to Enhance the IQE for DUV LEDs

2019
The very low doping efficiency for the p-type Al-rich AlGaN layers indicates that the hole injection capability for DUV LEDs can be poor. Therefore, we ought to investigate the approaches to enable high-efficiency hole injection. In this chapter, we propose novel DUV LED architectures to make “hot” holes, increase the hole concentration in the p-type ...
Zi-Hui Zhang, Chunshuang Chu, Kangkai Tian, Yonghui Zhang   +3 more
openaire   +1 more source

Increase the IQE by Improving the Crystalline Quality for DUV LEDs

2019
The roadmap for AlGaN based DUV LEDs is similar to that for InGaN based visible LEDs, such that the success of achieving high crystalline-quality epilayers is the precondition for fabricating high-brightness DUV LEDs. This chapter will review the most adopted technologies for growing high-quality Al-rich AlGaN films, which is regarded as the milestone ...
Zi-Hui Zhang, Chunshuang Chu, Kangkai Tian, Yonghui Zhang   +3 more
openaire   +1 more source

Enhanced Light Extraction From DUV-LEDs by AlN-Doped Fluoropolymer Encapsulation

IEEE Photonics Technology Letters, 2017
AlN-doped fluoropolymer encapsulation layer was proposed for deep-ultraviolet light-emitting diodes. The proposed method can significantly enhance the light extraction from the chip-on-board packaging structure, which is attributed to the increased refractive index and light scattering ability of the encapsulant layer by the doping of AlN nanoparticles
Yang Peng, Xin Guo, Renli Liang, Hao Cheng, Mingxiang Chen   +4 more
openaire   +1 more source

Screen the Polarization Induced Electric Field Within the MQWs for DUV LEDs

2019
This chapter discusses and presents different designs to screen the polarization level in the quantum wells for [0001]-oriented DUV LEDs. By doing so, the quantum confined Stark effect (QCSE) can be decreased. We suggest a simple way to reduce the QCSE by adopting Si-doped quantum barriers.
Zi-Hui Zhang, Chunshuang Chu, Kangkai Tian, Yonghui Zhang   +3 more
openaire   +1 more source

On the origin of the enhanced light extraction efficiency of DUV LED by using inclined sidewalls

Optics Letters
It is known that light extraction efficiency (LEE) for AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) can be enhanced by using an inclined sidewall of mesa. However, the reported optimal inclined angles are different. In this work, to explore the origin for enhancing the LEE of DUV LED by using inclined sidewalls, we investigate the ...
Liu Wang, Tong Jia, Zhaoqiang Liu, Chunshuang Chu, KangKai Tian, Yonghui Zhang, Zi-Hui Zhang   +6 more
openaire   +2 more sources

Modulating the Layer Resistivity by Band-Engineering to Improve the Current Spreading for DUV LEDs

IEEE Photonics Technology Letters, 2019
In this letter, we propose to enhance the hole injection efficiency by modulating the layer resistivity in the n-AlGaN layer for 280 nm AlGaN based deep ultraviolet light-emitting diodes (DUV LEDs). The layer resistivity for the n-AlGaN layer is controlled by generating the energy barriers, which is enabled by locally engineering the energy band gap ...
Chunshuang Chu, Qian Chen, Kangkai Tian, Jiamang Che, Hua Shao, Jianquan Kou, Yonghui Zhang, Changqing Chen, Zi-Hui Zhang, Jiangnan Dai   +9 more
openaire   +1 more source