${\mathrm{SnO}}_2$ has attracted considerable attention due to its wide bandgap, large exciton binding energy, and outstanding electrical and optoelectronic features. Owing to the lack of reliable and reproducible p-type ${\mathrm{SnO}}_2$, many challenges on developing ${\mathrm{SnO}}_2$-based optoelectronic devices and their practical applications still remain. Herein, single-crystal ${\mathrm{SnO}}_2$ microwires (MWs) are acquired via the self-catalyzed approach. As a strategic alternative, ${\mathrm{n}\text{-}\mathrm{SnO}}_2$ MW/p-GaN heterojunction was constructed, which exhibited selectable dual-functionalities of light-emitting and photodetection when operated by applying an appropriate voltage. The device illustrated a distinct near-ultraviolet light-emission peaking at $\sim 395.0\mathrm{nm}$ and a linewidth $\sim 50\mathrm{nm}$. Significantly, the device characteristics, in terms of the main peak positions and linewidth, are nearly invariant as functions of various injection current, suggesting that quantum-confined Stark effect is essentially absent. Meanwhile, the identical $\mathrm{n}\text{-}{\mathrm{SnO}}_2$ MW/p-GaN heterojunction can also achieve photovoltaic-type light detection. The device can steadily feature ultraviolet photodetecting ability, including the ultraviolet/visible rejection ratio ($R_{360\mathrm{nm}}/R_{400\mathrm{nm}}$) $\sim 1.5\times {10}^3$, high photodark current ratio of ${10}^5$, fast response speed of 9.2/51 ms, maximum responsivity of 1.5 A/W, and detectivity of $1.3\times {10}^{13}$ Jones under 360 nm light at $-3\mathrm{V}$ bias. Therefore, the bifunctional device not only displays distinct near-ultraviolet light emission, but also has the ability of high-sensitive ultraviolet photodetection. The novel design of ${\mathrm{n}\text{-}\mathrm{SnO}}_2$ MW/p-GaN heterojunction bifunctional systems is expected to open doors to practical application of ${\mathrm{SnO}}_2$ microstructures/nanostructures for large-scale device miniaturization, integration and multifunction in next-generation high-performance photoelectronic devices.

中文翻译：

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基于SnO2微线/p-GaN异质结的双功能紫外发光/检测装置

${\mathrm{氧化锡}}_2$由于其宽禁带、大激子结合能以及出色的电学和光电特性而引起了广泛关注。由于缺乏可靠和可重复的 p 型${\mathrm{氧化锡}}_2$, 发展面临诸多挑战 ${\mathrm{氧化锡}}_2$的光电器件及其实际应用仍然存在。其中，单晶${\mathrm{氧化锡}}_2$微丝（MW）是通过自催化方法获得的。作为战略选择，${\mathrm{n}\text{——}\mathrm{氧化锡}}_2$构建了 MW/p-GaN 异质结，当通过施加适当的电压操作时，该异质结表现出可选择的发光和光电检测双重功能。该装置显示了明显的近紫外光发射峰值$～395.0\mathrm{纳米}$ 和线宽 $～50\mathrm{纳米}$. 值得注意的是，在主峰位置和线宽方面，器件特性几乎是各种注入电流的函数，这表明基本上不存在量子限制的斯塔克效应。同时，相同的$\mathrm{n}\text{——}{\mathrm{氧化锡}}_2$MW/p-GaN异质结也可以实现光伏型光检测。该器件可以稳定地具有紫外光检测能力，包括紫外/可见光抑制比（${\mathrm{电阻}}_{360\mathrm{纳米}}/{\mathrm{电阻}}_{400\mathrm{纳米}}$) $～1.5\times {10}^3$, 高光暗电流比 ${10}^5$, 9.2/51 ms 的快速响应速度，1.5 A/W 的最大响应度，以及 $1.3\times {10}^{13}$ 琼斯在 360 nm 光下 $-3\mathrm{伏}$偏见。因此，该双功能器件不仅显示出明显的近紫外光发射，而且还具有高灵敏度的紫外光电探测能力。新颖的设计${\mathrm{n}\text{——}\mathrm{氧化锡}}_2$ MW/p-GaN异质结双功能系统有望为实际应用打开大门 ${\mathrm{氧化锡}}_2$ 用于下一代高性能光电器件中大规模器件小型化、集成和多功能化的微结构/纳米结构。