As compared to solar-blind ultraviolet (UV) photodetectors (PDs), far-UVC PDs not only show some irreplaceable advantages but also are more challenging to be developed. To solve this challenge, we report herein a soft template-assisted solvothermal route to synthesize ultrathin γ-Ga₂O₃ quantum wires (UQWs) with diameters down to 1–2 nm. These UQWs all exhibit a cluster-like absorption feature with a strong peak located between 190 and 230 nm and an edge below 250 nm, allowing highly selective absorption to far-UVC light. Notably, their normalized absorption coefficients were experimentally and theoretically confirmed to increase obviously with decreasing their diameters. Self-powered photoelectrochemical-type PDs based on Ga₂O₃ QWs of 1.7 nm diameter were therefore fabricated, exhibiting an excellent far-UVC detection performance with an unprecedented ultrahigh spectral selectivity (R_210 nm/R_250 nm = 452). As a proof of concept, this paper offers a new idea for developing ultrawide bandgap semiconductor materials and devices by leveraging a strong quantum confinement effect.

中文翻译：

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湿法化学合成超薄 γ-Ga2O3 量子线，实现具有超高选择性和灵敏度的远 UVC 光电检测

与日盲紫外（UV）光电探测器（PD）相比，远UVC PD不仅具有一些不可替代的优势，而且开发起来更具挑战性。为了解决这一挑战，我们在此报告了一种软模板辅助溶剂热路线来合成直径低至1-2 nm的超薄γ-Ga ₂ O ₃量子线（UQW）。这些 UQW 均表现出簇状吸收特征，强峰位于 190 至 230 nm 之间，边缘低于 250 nm，从而可以对远 UVC 光进行高度选择性吸收。值得注意的是，实验和理论上证实它们的归一化吸收系数随着直径的减小而明显增加。因此，基于1.7 nm直径的Ga ₂ O ₃ QWs的自供电光电化学型PD被制备出来，表现出优异的远UVC检测性能和前所未有的超高光谱选择性（R _{210 nm} / R _{250 nm} = 452）。作为概念证明，本文提供了利用强量子限制效应开发超宽带隙半导体材料和器件的新思路。