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）在柔性自供电非晶Ga2O3基日盲紫外光电探测器研究中取得进展。该团队将银纳米线嵌入在非晶Ga2O3薄膜中（a-Ga2O3@Ag NWs）,能有效降低电荷转移电阻和势垒，增强Ag NWs/a-Ga2O3界面的内置电场，协同促进电子的高效传输，实现了高性能柔性自供电a-Ga2O3@Ag NWs电光电化学型日盲深紫外光电探测器。相关成果以"Flexible and Self-Powered Photoelectrochemical-Type Solar-Blind Photodetectors Based on Ag Nanowires-Embedded Amorphous Ga2O3 Films"为题发表在《Advanced Optical Materials》杂志上。团队本科生余辰曦和李泓霖副教授为共同一作，李万俊教授、唐燕博士和叶利娟副教授为共同通讯作者。
日盲深紫外（200 nm~280 nm）光电探测技术，以其对太阳光背景噪声的强“免疫性”，展现出卓越的灵敏度和极低的虚警率，在非视距保密通信、导弹预警、空间探测、臭氧层监测、火焰探测、电晕检测以及生物检测等诸多军民应用领域展现出巨大潜力。尽管当前基于光电倍增管(PMT)和硅基光电探测器的日盲紫外成像设备已相对成熟，但PMT因其体积大、成本高昂以及高电压要求等局限性，在深紫外线中的应用受到制约。硅基光电二极管需依赖昂贵的滤光片来阻挡波长大于280 nm的光，进一步增加成本。因此，开发新型、经济高效的日盲深紫外探测技术是当前的研究热点。近年来，超宽带氧化镓(Ga2O3) 以其超宽的禁带（约4.5~5.3 eV）、高击穿场强、高透明度及优异的稳定性等特点，成为研制高性能日盲深紫外探测器的理想之选。
为此，团队以一种简单且低成本的方式，在铟锡氧化物涂层聚萘乙酸乙二醇酯（ITO/PEN）基底上，通过一步溅射法制备了非晶氧化镓（a-Ga2O3）薄膜，进而构建了用于日盲深紫外探测的新型光电化学型光电探测器件（PEC-PDs）。为了进一步提升器件性能，将银纳米线（Ag NWs）嵌入在a-Ga2O3薄膜中制备了高性能自供电a-Ga2O3@Ag NWs PEC-PDs。基于实验和理论计算，证实了Ag NWs的引入不仅降低了电荷转移电阻和势垒，还增强了银纳米线/a-Ga2O3界面的内置电场，从而协同促进了电子的高效传输。因此，相较于a-Ga2O3 PEC-PDs，经Ag NW修饰的PEC-PDs的关键性能参数（包括响应度11.23 mA/W和响应时间0.07/0.09 s）提升了近两倍。此外，Ag NW修饰的PEC-PDs还展现出卓越的机械柔韧性和出色的疲劳耐久性，在经受500次弯曲循环后，仍能维持约95%的初始光响应电流和响应度。这项研究为通过精细的光阳极工程设计研制高性能柔性自供电PEC-PD提供了有益参考。
Figure 1. a) Schematic diagram of a typical PEC system built for evaluating the photoresponse behaviors of the Ga2O3/ITO/PEN PEC-PD. b) Mechanism diagram of self-powered PEC-PD based on Ga2O3/ITO/PEN. c) Photoresponse behavior of Ga2O3 PEC-PDs with different sputtering times (or film thickness) at 0 V. d) AFM image of Ga2O3/ITO/PEN. e) SEM surface morphology of Ga2O3/ITO/PEN. f) Transmittance spectra of Ga2O3/ITO/PEN, ITO/PEN, and Ga2O3/Al2O3. g) Photograph of transparent Ga2O3/ITO/PEN photoanode.
Figure 2. a) Schematic illustration of the fabrication process of a-Ga2O3@Ag NWs photoanodes. b) and c) schematic diagram of the selected testing area and EDS spectrum, respectively (with elements mapping of a-Ga2O3@Ag NWs as shown in the inset). d,e) SEM morphologies of the local surface of Ag NWs and a-Ga2O3@Ag NWs. f) SEM morphology of the cross-section of a-Ga2O3@Ag NWs.
Figure 3. a) I–t photoresponses of a-Ga2O3@Ag NWs PEC-PDs at 0 V with varying spinning thicknesses. b) Current density vs spinning thickness. c) I–t photoresponses under switching wavelength lights (𝜆 = 254, 365 nm), with comparison to the photoresponse of bare Ag NWs/ITO/PEN PEC-PD under 254 nm light. d) I–t characteristics of a-Ga2O3@Ag NWs PEC-PDs at 0 V with different incident 254 nm light intensities. e) Photocurrent density and Responsivity as functions of light intensity at 0 V. f) Detectivity and external quantum efficiency as functions of light intensity at 0 V. g–i) Performance comparison between a-Ga2O3 and a-Ga2O3@Ag NWs PEC-PDs. j) Electrochemical impedance spectra plots for a-Ga2O3 and a-Ga2O3@Ag NWs PECPDs. k) Device stability.
Figure 4. The averaged electrostatic potential of the a) ITO, b) Ag, and c) a-Ga2O3. The averaged electrostatic potential of d) ITO/a-Ga2O3 and e) Ag/a-Ga2O3. f) The 3D and 2D charge density difference of g) ITO/a-Ga2O3 and h) Ag/a-Ga2O3. The difference is drawn under an isosurface of 0.008 e Å−1. The yellow/red areas correspond to charge accumulation, and the cyan/blue corresponds to charge depletion.
Figure 5. a) The structure diagram of the a-Ga2O3@Ag NWs photoanode. b)Photograph of curved a-Ga2O3@Ag NWs PEC-PD. The I–t photoresponses of the a-Ga2O3 PEC-PD at various bending c) angles and e) times. The corresponding photocurrent density and responsivity without bending d) and with bending angle of 60°f), respectively. The I–t photoresponses of the a-Ga2O3@Ag NWs PEC-PD at various bending g) angles and i) times. The corresponding photocurrent density and responsivity under two bending conditions are shown in (j) and (k), respectively.
论文信息：
Chenxi Yu#(本科生), Honglin Li#, Ke Ding, Lijuan Huang, Hong Zhang, Di Pang, Yuanqiang Xiong, Ping-An Yang, Liang Fang, Wanjun Li*, Yan Tang*, Lijuan Ye* and Chunyang Kong. Flexible and Self-Powered Photoelectrochemical-type Solar-Blind Photodetectors based on Ag Nanowires-Embedded Amorphous Ga2O3 films. Advanced Optical Materials, 2024, 2400116.
论文链接：
https://doi.org/10.1002/adom.202400116.
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
