Mixed-dimension van der Waals (vdW) p-n heterojunction photodiodes have inspired worldwide efforts to combine the excellent properties of 2D materials and traditional semiconductors without consideration of lattice mismatch. However, owing to the scarcity of intrinsic p-type semiconductors and insufficient optical absorption of the few layer 2D materials, a high performance photovoltaic device based on a vdW heterojunction is still lacking. Here, a novel mixed-dimension vdW heterojunction consisting of 1D p-type Se nanotubes and a 2D flexible n-type InSe nanosheet is proposed by a facile method, and the device shows excellent photovoltaic characteristics. Due to the superior properties of the hybrid p-n junction, the mix-dimensional van der Waals heterojunction exhibited high on/off ratios (103) at a relatively weak light intensity of 3 mW cm-2. And a broadband self-powered photodetector ranging from the UV to visible region is achieved. The highest responsivity of the device could reach up to 110 mA W-1 without an external energy supply. This value is comparable to that of the pristine Se device at 5 V and InSe device at 0.1 V, respectively. Furthermore, the response speed is enhanced by one order of magnitude over the single Se or InSe device even at a bias voltage. This work paves a new way for the further development of high performance, low cost, and energy-efficient photodetectors by using mixed-dimensional vdW heterostructures.

中文翻译：

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用于高响应性自供电光电探测器的一维二维一维Se-2D InSe范德华异质结。

混合尺寸范德华（vdW）pn异质结光电二极管激发了全球范围内努力将2D材料和传统半导体的优异性能相结合而又不考虑晶格失配的努力。然而，由于本征p型半导体的稀缺和少数几层2D材料的光吸收不足，仍然缺乏基于vdW异质结的高性能光伏器件。在这里，通过一种简便的方法，提出了一种由一维p型硒纳米管和二维柔性n型InSe纳米片组成的新型混合尺寸vdW异质结，该器件显示出优异的光伏特性。由于混合pn结的优异性能，混合尺寸的范德华异质结在3 mW cm-2的相对较弱的光强度下表现出高的开/关比（103）。从而实现了从紫外线到可见光范围的宽带自供电光电探测器。在没有外部电源的情况下，设备的最高响应度可以达到110 mA W-1。该值分别相当于原始电压为5 V的Se器件和电压为0.1 V的InSe器件的值。此外，即使在偏置电压下，响应速度也比单个Se或InSe器件提高了一个数量级。这项工作通过使用混合尺寸的vdW异质结构，为进一步开发高性能，低成本和高能效的光电探测器铺平了新的道路。该值分别相当于原始电压为5 V的Se器件和电压为0.1 V的InSe器件的值。此外，即使在偏置电压下，响应速度也比单个Se或InSe器件提高了一个数量级。这项工作通过使用混合尺寸的vdW异质结构，为进一步开发高性能，低成本和高能效的光电探测器铺平了新的道路。该值分别相当于原始电压为5 V的Se器件和电压为0.1 V的InSe器件的值。此外，即使在偏置电压下，响应速度也比单个Se或InSe器件提高了一个数量级。这项工作通过使用混合尺寸的vdW异质结构，为进一步开发高性能，低成本和高能效的光电探测器铺平了新的道路。