Ultrathin LED technology helps advance 6G
Ultrathin LED technology helps advance 6G lead image
5G communications networks might have just arrived, but already scientists are working on 6G. A key component of 6G is visible light communication (VLC), which modulates the visible light from LEDs in illumination systems, such as lamps and TVs, to wirelessly send information at higher rates and over longer distances.
However, traditional LEDs have several limitations that prevent their usage in VLC, including challenges to increasing modulation bandwidth for large chip sizes. Gallium nitride LEDs have shown promise for addressing these limitations in a wide range of next-generation lighting technology, Xie et al. tested their use with subwavelength vertical-structure LEDs, or VSLEDs, which have shown better heat dissipation and current spreading than traditional LEDs.
The authors created a one square millimeter, 580-nm-thick VSLED mounted on a 2-inch metal-based bonded III-nitride-on-silicon wafer. Testing the device with a bit-loading discrete multitone modulation scheme, the ultrathin VLSED achieved a data transmission rate of 608 Mbps. For comparison, a similar sized LED would transmit only tens of Mbps.
The device was also able to enhance light extraction efficiency and increase modulation bandwidth, two requirements for 6G technology. Additionally, the subwavelength VSLED was free of internal lateral light propagation, which solves an issue with previous designs that suffered from optical crosstalk.
“Our monolithic gallium nitride optoelectronic system integrates key components, such as an optical transmitter, waveguide, modulator and receiver, into a single gallium nitride chip, which makes it a promising option for advanced computing architecture in a 6G era,” said author Yongjin Wang.
The researchers plan to continue their work by fabricating and packaging blue and green subwavelength VSLEDs on a 4-inch gallium nitride wafer. They hope to optimize device design and the fabrication process.
Source: “580-nm-thick vertical-structure light-emitting diode for visible light communication,” by Mingyuan Xie, Fangchen Hu, Chicheng Ma, Yan Jiang, Zheng Shi, Xumin Gao, Bolun Jia, Jialei Yuan, Hongbo Zhu, Nan Chi, and Yongjin Wang, Applied Physics Letters (2022). The article can be accessed at https://doi.org/10.1063/5.0088846 .
