Broadband photodetection including midwave infrared (MWIR) is crucial in space science and technology. Topological insulators Bi₂Se₃ have exhibited excellent performance in infrared. However, the large dark current caused by topological surface states impedes further photodetection capability enhancement. Here, we designed and integrated the Bi₂Se₃/BP van der Waals p-n heterojunction to suppress dark current. The built-in electric field and clean, sharp interface at heterojunctions drive excellent photoresponse of the Bi₂Se₃/BP photodetector from visible to mid-infrared (520–4250 nm) with the fastest response time reaching 92 μs (τ_rising) and 84 μs (τ_falling), 3 orders of magnitude faster than Bi₂Se₃ detector. The responsivity (R) and detectivity (D*) can reach up to 1.13 A W^-1 and 7.8 × 10⁹ cm Hz^1/2 W^-1, respectively, at 2 μm under 0 bias. Due to the asymmetric lattice structure of BP, the heterojunction device displays outstanding polarization-resolved photoelectric response, with a polarization ratio of up to 20.1 at 2 μm. Moreover, the device exhibits a significant blackbody response and excellent imaging capabilities. This work may pave a way for designing high-performance midwave infrared photodetectors.

中文翻译：

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用于中波红外光电探测的低暗电流拓扑绝缘体 Bi2Se3 异质结


包括中波红外（MWIR）在内的宽带光电探测在空间科学和技术中至关重要。拓扑绝缘体Bi ₂ Se ₃ 在红外方面表现出优异的性能。然而，拓扑表面态引起的大暗电流阻碍了光电探测能力的进一步增强。在这里，我们设计并集成了 Bi ₂ Se ₃ /BP van der Waals p-n 异质结来抑制暗电流。异质结处的内置电场和干净、锐利的界面驱动 Bi ₂ Se ₃ /BP 光电探测器从可见光到中红外 (520–4250 nm) 的出色光响应，最快响应时间达到 92 μs (τ _rising ) 和 84 μs (τ _falling )，比 Bi ₂ Se ₃ 和7.8 × 10 ⁹ cm Hz ^1/2 W ^-1