Breaking the Responsivity-Bandwidth Trade-Off Limit in GaN Photoelectrodes for High-Response and Fast-Speed Optical Communication Application

作者：Fang, Shi; Li, Liuan; Wang, Danhao; Chen, Wei; Kang, Yang; Wang, Weiyi; Liu, Xin; Luo, Yuanmin; Yu, Huabin; Zhang, Haochen; Memon, Muhammad Hunain; Hu, Wei; He, Jr-Hau; Gong, Chen; Zuo, Chengjie; Liu, Sheng; Sun, Haiding^*

来源：Advanced Functional Materials, 2023, 33(37).

DOI：10.1002/adfm.202214408

• gallium nitride nanowires
• photoelectrodes
• responsivity-bandwidth trade-off
• surface decoration
• underwater optical communication

Underwater optical communication (UOC) has attracted considerable interest in the continuous expansion of human activities in marine/ocean environments. The water-durable and self-powered photoelectrodes that act as a battery-free light receiver in UOC are particularly crucial, as they may directly face complex underwater conditions. Emerging photoelectrochemical (PEC)-type photodetectors are appealing owing to their intrinsic aqueous operation characteristics with versatile tunability of photoresponses. Herein, a self-powered PEC photodetector employing n-type gallium nitride (GaN) nanowires as a photoelectrode, which is decorated with an iridium oxide (IrOx) layer to optimize charge transfer dynamics at the GaN/electrolyte interface, is reported. Strikingly, the constructed n-GaN/IrOx photoelectrode breaks the responsivity-bandwidth trade-off limit by simultaneously improving the response speed and responsivity, delivering an ultrafast response speed with response/recovery times of only 2 mu s/4 mu s while achieving a high responsivity of 110.1 mA W-1. Importantly, the device exhibits a large bandwidth with 3 dB cutoff frequency exceeding 100 kHz in UOC tests, which is one of the highest values among self-powered photodetectors employed in optical communication system.

• 单位
  武汉大学; 中国科学院