Two-dimensional van der Waals heterostructures exhibit distinctive electronic and optoelectronic properties, making them promising structures for constructing advanced multifunctional devices. However, devices based on conventional charge-carrier transport mechanisms often perform only a single function, which limits its integration and performance. Here, we present a vertical van der Waals heterostructure made of Bi2O2Se and MoTe2, allowing it to act as high-performance backward diode, forward diode, photodetector and photovoltaic device at various working conditions. The applications are enabled by band-alignment switching between p–n heterostructure controlled by minority carrier diffusion and n–n heterostructure governed by the thermionic emission and tunneling-mediated processes. As a backward diode, the device displays a high reverse rectification ratio of 5.0 × 104. As a photodetector, the device demonstrates a broad spectral photoresponse ranging from ultraviolet (365 nm) to near-infrared (1050 nm). When irradiated by 532 nm laser, the photodetector shows a responsivity of up to 11.6 A/W and achieves quick response/recovery speed of 19.6/8.8 μs. As a photovoltaics device, an external quantum efficiency of 78% and a responsivity of 0.33 A/W are observed. This study showcases the potential for high-performance multifunctional devices utilizing Bi2O2Se/MoTe2 heterostructures and provides comprehensive insights into the designed band alignment and its applications.

中文翻译：

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用于高性能多功能器件的 Bi2O2Se/MoTe2 范德华异质结构


二维范德华异质结构表现出独特的电子和光电特性，使其成为构建先进多功能器件的有前途的结构。然而，基于传统电荷载流子传输机制的器件通常仅执行单一功能，这限制了其集成和性能。在这里，我们提出了一种由 Bi2O2Se 和 MoTe2 制成的垂直范德华异质结构，使其能够在各种工作条件下充当高性能后向二极管、前向二极管、光电探测器和光伏器件。这些应用是通过少数载流子扩散控制的 p-n 异质结构和热电子发射和隧道介导过程控制的 n-n 异质结构之间的能带对准切换来实现的。作为反向二极管，该器件具有 5.0 × 104 的高反向整流比。作为光电探测器，该器件表现出从紫外 (365 nm) 到近红外 (1050 nm) 的宽光谱光响应。当受到532 nm激光照射时，光电探测器的响应度高达11.6 A/W，并实现19.6/8.8 μs的快速响应/恢复速度。作为光伏器件，外量子效率为 78%，响应率为 0.33 A/W。这项研究展示了利用 Bi2O2Se/MoTe2 异质结构的高性能多功能器件的潜力，并为设计的能带排列及其应用提供了全面的见解。