Tang Xiaoqiu, Wang Shuai, Liang Yao, Bai Dongwei, Xu Jiyuan, Wang Yingying, Chen Chaoyu, Liu Xiang, Wu Sumei, Wen Yang, Jiang Dayong, Zhang Zhihua
School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028, P. R. China.
Department of Optoelectronic Science, Harbin Institute of Technology at Weihai, Weihai 264209, P. R. China.
Phys Chem Chem Phys. 2022 Mar 23;24(12):7323-7330. doi: 10.1039/d1cp05602f.
With an urgent demand for low-energy-consumption and wearable devices, it is desirable to find an easy, effective, and low-cost method to fabricate self-powered flexible photodetectors with simple configurations and high-performance. Self-powered photodetectors are normally fabricated based on either two different materials or the same material in contact with two different metal electrodes. Here, a flexible MoS photodetector with the same Au electrodes was fabricated on a polyethylene terephthalate (PET) substrate which exhibits self-powered properties. To our knowledge, its configuration is the simplest, and the fabrication process is easy to implement. At a bias of 0 V, the photodetector exhibits a high responsivity of 431 mA W, a short response/recovery time of 40 ms/40 ms, and excellent flexibility. Compared with those at a bias of 2 V, a dark current is sufficiently suppressed, and the response/recovery speed is significantly improved. It is found that the driving force of the self-powered photodetector is provided by the asymmetric Schottky barriers originating from the spontaneous generation of two van der Waals gaps with different widths. The asymmetric barriers exist stably at the interfaces between the 2D material and Au electrodes as further observed for ReS or GaSe flakes, which show the generality of asymmetric Schottky barriers between the 2D material and Au electrodes. The discovery here thus gives a new way to generate asymmetric Schottky barriers and develop high-performance self-powered photodetectors.
随着对低能耗和可穿戴设备的迫切需求，需要找到一种简单、有效且低成本的方法来制造具有简单结构和高性能的自供电柔性光电探测器。自供电光电探测器通常基于两种不同材料或同一种材料与两种不同金属电极接触来制造。在此，在具有自供电特性的聚对苯二甲酸乙二醇酯（PET）基板上制造了一种带有相同金电极的柔性MoS光电探测器。据我们所知，其结构是最简单的，并且制造过程易于实现。在0 V偏压下，该光电探测器表现出431 mA/W的高响应度、40 ms/40 ms的短响应/恢复时间以及出色的柔韧性。与2 V偏压下的情况相比，暗电流得到充分抑制，响应/恢复速度显著提高。研究发现，自供电光电探测器的驱动力由源自自发产生的两个不同宽度范德华间隙的不对称肖特基势垒提供。如对ReS或GaSe薄片进一步观察到的那样，不对称势垒稳定存在于二维材料与金电极之间的界面处，这表明二维材料与金电极之间不对称肖特基势垒具有普遍性。因此，这里的发现为产生不对称肖特基势垒和开发高性能自供电光电探测器提供了一种新方法。
