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）在光电化学型自供电日盲深紫外光电探测器研究中取得进展。该团队基于CVD技术，实现了β-Ga2O3@a-Ga2O3核壳纳米阵列的无催化生长，并研制出高灵敏的光电化学型自供电日盲深紫外光电探测器。相关成果以“Catalyst-Free β-Ga2O3@a-Ga2O3 Core−Shell Nanorod Arrays Grown on Si substrate for High-performance self-powered solar-blind photoelectrochemical photodetection”为题发表在《Applied Surface Science》杂志上。团队本科生冯雨为第一作者，张红博士、李泓霖副教授和李万俊教授为共同通讯作者。
日盲深紫外光电探测器（PDs）由于具有低背景信号的天然优势，在民用和军事领域有着巨大的应用前景，包括火灾报警、安全通信、导弹跟踪和环境监测等。然而，传统的光电探测器通常需要外部电源来实现高性能，这阻碍了其在无线监测和传感中的应用。因此，寻找低成本、高性能、自供电的日盲紫外光电探测器是实现下一代节能、可持续的集成光电系统的关键。
本研究工作基于新型超宽带半导体Ga2O3材料，利用无催化剂的化学气相沉积（CVD）生长技术，首次在易集成的Si衬底上构筑了β-Ga2O3@a-Ga2O3核−壳纳米棒阵列，开发出无光刻工艺、低成本的新型光电化学（PEC）型自供电日盲紫外光电探测器件。该器件的响应率高达48.4 mA/W，探测度为8.5×1011Jones，响应和恢复时间较快，性能处于国际先进水平。本研究为构建基于超宽带半导体Ga2O3材料的高性能、高稳定性、低成本的新型光电化学型日盲紫外光电探测器提供了一种简单可行的途径。
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Fig. 1. The crystal structure and morphology of a typical β-Ga2O3@a-Ga2O3 nanorod arrays grown on the Si substrate at 900 ◦C for 10 min. (a) Preparation process, (b) Top-view SEM of β-Ga2O3@a-Ga2O3 nanorod arrays. Inset: Corresponding cross-sectional SEM image. (c) EDS spectrum, (d) TEM image and (e) HR-TEM image of a single β-Ga2O3@a-Ga2O3 nanorod.
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Fig. 2. Characterizations of β-Ga2O3@a-Ga2O3 nanorod arrays. (a) XRD pattern, (b) Raman spectra, and (c) XPS survey spectrum of β-Ga2O3 arrays. High-resolution XPS spectra of O 1s core level (e) and Ga 3d core level (d) of β-Ga2O3@a-Ga2O3 nanorod arrays. (f) Tauc plot of a typical β-Ga2O3 nanorod array on Si substrate.
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Fig. 3. SEM images of β-Ga2O3@a-Ga2O3 nanorod arrays synthesized at 900 °C for (a1-a3) 3 min, (b1-b3) 5 min, (c1-c3) 10 min and (d1-d3) 15 min.
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Fig. 4. Self-powered on/off switching response characteristics of β-Ga2O3@a-Ga2O3 nanorod arrays synthesized at 900 °C for various growth times. (a) Typical three-electrode PEC system for evaluating the photoresponse behaviors of the β-Ga2O3@a-Ga2O3 photodetector in the Na2SO4 electrolyte. (b) The photocurrent density under 254 and 365 nm (0.5 mW/cm2) for sample synthesized at 900 °C for 10 min. (c) Photoresponse switching behaviors of β-Ga2O3@a-Ga2O3 nanorod arrays. (e) Photoresponsivity and detectivity as functions of growth time. (f) Representation of the rise time (tres) and decay time (trec) interval. Inset: enlarged light on/off cycle for the self-powered PEC PD illuminated by 254 nm (0.5 mW/cm2).
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Fig. 5. Photoelectric response characteristics of the β-Ga2O3@a-Ga2O3 PEC PD (10 min). (a) Photoresponse of a self-powered β-Ga2O3@a-Ga2O3 PEC PD illuminated by 254 nm (0.5 mW/cm2) with various light power intensities from 0.1 to 0.9 mW/cm2. (b, c) Corresponding R and D* values and t_res/t_rec under light power intensities. (d) Photoresponse of β-Ga2O3@a-Ga2O3 PEC PD illuminated by 254 nm (0.5 mW/cm2) and various bias from -0.1 V to 0.7 V. (e, f) Corresponding R and D* values and t_res/t_rec under different bias potential. (g) Long-time stability testing of β-Ga2O3@a-Ga2O3 PEC PD illuminated by 254 nm (0.5 mW/cm2) without extra bias. (h) Comparison of the characteristic parameters of self-powered β-Ga2O3@a-Ga2O3 nanorod PEC PDs and other previously Ga2O3 based photodetectors
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Fig. 6. (a, b) The 3D and 2D charge density difference of β-Ga2O3/amorphous phase, respectively. The difference is drawn under an isosurface of 0.006 e/Å. The yellow areas correspond to charge accumulation, while the cyan corresponds to charge depletion. (c) Averaged potential profile along z axis of β-Ga2O3 and amorphous phase Ga2O3.论文信息：u Feng(本科生), Linfeng Lv(本科生), Hong Zhang*, Lijuan Ye, Yuanqiang Xiong, Liang Fang, Chunyang Kong, Honglin Li* and Wanjun Li*. Catalyst-Free β-Ga2O3@a-Ga2O3 Core−Shell Nanorod Arrays Grown on Si substrate for High-performance self-powered solar-blind photoelectrochemical photodetection. Applied Surface Science, 2023, 624, 157149.
论文连接：
https://doi.org/10.1016/j.apsusc.2023.157149
