重庆师范大学李万俊教授团队（宽带隙半导体材料与器件团队）在自供电ZnO基紫外光电探测器研究中取得进展。该团队采用Ga掺杂策略提升了ZnO基光电化学型自供电紫外光电探测器性能，器件响应度高达233.26 mA/W，并概念性验证了其在光通信的应用潜力。相关成果以"Enhanced photoresponse of self-powered ZnO-based photoelectrochemical-type UV photodetectors via Ga-doping for optical communication application"为题发表在《Journal of Alloys and Compounds》杂志上。团队本科生唐七鑫为第一作者，张红博士、叶利娟副教授和李万俊教授为共同通讯作者。
本工作针对当前光电化学型紫外光电探测器中ZnO材料面临的光生载流子分离效率低和导电性差的核心问题，提出了Ga掺杂优化策略，实现了高性能、低成本、低能耗的紫外光电探测器，优于已报道的同类器件的结果，并从微观层面解释了其探测性能提高的内在物理机制。同时，搭建了紫外光通讯系统，验证了该探测器在通信领域的应用潜力，为未来传感、通信和成像系统中的多功能光电器件的开发提供了重要基础。
Fig. 1. Structural and morphological characterizations. (a) X-ray diffraction patterns and (b-c) Top-view SEM images depicting the as-prepared ZnO and ZnO:Ga samples. (d) EDS elemental mapping, (e) HRTEM image, and (f) corresponding fast Fourier transform (FFT) pattern along the [010] zone of the single ZnO:Ga nanowire, respectively. (g-i) Well-resolved XPS peaks of Ga 2p, Zn 2p, and O 1 s of as-prepared ZnO and ZnO:Ga samples, respectively.
Fig. 2. Comparison of photoelectrochemical performance of ZnO based PEC-type PDs under 365 nm irradiation. (a) Schematic illustration depicting the assessment process of ZnO photoanodes. (b) I–t response curves of ZnO and ZnO:Ga PEC PDs under various light power intensities at 0 V bias in 0.5 M Na2SO4. (c) Corresponding photocurrent density, (d) EQE, (e) R, and (f) D* versus varying light power intensity for ZnO and ZnO:Ga PEC PDs, respectively. (g) Normalized responsivity as a function of wavelength for the ZnO:Ga PEC-type photodetector at 0 V bias.
Fig. 3. Charge transport mechanism. (a) Mott-Schottky (M–S) curves. (b) Illustration of band structures and band bending for ZnO and ZnO:Ga nanowires, showcasing the charge transfer occurring at the interface region between the semiconductor and electrolyte. (c) EIS plots recorded in 0.5 M Na2SO4 electrolyte without illumination. Inset: depiction of the equivalent circuit model used to fit the EIS data.
Fig. 4. High PEC properties and stability of ZnO:Ga PEC-PDs. (a) I–t curves for various concentration of Na2SO4 electrolyte (0.01, 0.1, 0.5, and 1 M) at 0 V under 365 nm illumination with 500 μW/cm2. (b) I–t curves for various external biases (− 0.1, 0, 0.1, 0.3, and 0.5 V) in 0.5 M Na2SO4 electrolyte under 365 nm illumination with 500 μW/cm2. (c) Corresponding photocurrent densities under different electrolyte concentration and external biases. (d, e) Depiction of the temporal intervals for rise and decay times for ZnO:Ga and ZnO PEC-PDs. (f) The comparison of detectivity and responsivity for self-Powered PEC UV PDs obtained in the present and previous work. (g) Multicycle and long-term stability tests of ZnO:Ga PEC PDs at a bias of 0 V and the irradiation of 500 μW/cm2 for 3600 s.
Fig. 5. Application in UV optical communication. (a) Schematic diagram of the UV optical communication setup utilizing the self-powered ZnO:Ga PEC-PD. (b) Morse code-encoded digital data waveforms received by the photodetector.
论文信息：
Qixin Tang(本科生), Guiying Tan, Hong Zhang*, Honglin Li, Yuanqiang Xiong, Di Pang, Lijuan Ye*, Liang Fang, Chunyang Kong, Wanjun Li*. Enhanced photoresponse of self-powered ZnO-based photoelectrochemical-type UV photodetectors via Ga-doping for optical communication application. Journal of Alloys and Compounds, 2024, 972: 172864.
论文链接：
https://doi.org/10.1016/j.jallcom.2023.172864.
此外，团队利用磁控溅射技术在碳纤维布上制备非晶氧化镓材料（a-Ga2O3/CC），构筑了光电化学型自供电日盲紫外探测器。结果表明，a-Ga2O3/CC光电探测器具有高响应率（16.98 mA/W）和快速响应（0.16/0.1 s）。基于实验和第一性原理计算揭示了a-Ga2O3与CC界面处形成的内置电场，可以有效地分离光生电子和空穴，同时抑制载流子的复合。最后，对a-Ga2O3/CC光电探测器件进行了疲劳测试（300次弯曲处理），发现器件仍能保持出色的光电特性，具有较好的稳定性。本工作为研制高性能氧化镓基柔性光电化学型自供电日盲紫外探测器提供一种参考。相关成果以"Flexible self-powered solar-blind UV photodetectors based on amorphous Ga2O3 modified carbon fiber cloth"为题发表在《Journal of Alloys and Compounds》杂志上。团队本科生张丹和研究生周欣为共同一作，李泓霖副教授和李万俊教授为共同通讯作者。
论文信息：
Dan Zhang#(本科生), Xin Zhou#, Yuanqiang Xiong, Hong Zhang, Lijuan Ye, Di Pang, Honglin Li*, Wanjun Li*. Flexible self-powered solar-blind UV photodetectors based on amorphous Ga2O3 modified carbon fiber cloth. Journal of Alloys and Compounds, 2023, 969: 172483.
论文链接：
https://doi.org/10.1016/j.jallcom.2023.172483.
重庆师范大学宽禁带半导体材料与器件团队
https://www.x-mol.com/groups/li_wanjun
