Guo Shuai, Chen Zhuo, Weller Dieter, Wang Xianshuang, Ding Chunjie, Wang Yingying, Liu Ruibin
Key Lab of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, P. R. China.
Department of Optoelectronic Science, Harbin Institute of Technology at Weihai, Weihai 264209, P. R. China.
ACS Appl Mater Interfaces. 2021 Dec 1;13(47):56438-56445. doi: 10.1021/acsami.1c14058. Epub 2021 Nov 16.
The unique optoelectronic properties of layered van der Waals (vdW) heterostructures open up exciting opportunities for high-performance photodetectors. Self-driven photodetectors are desirable for reducing power consumption and minimizing the device size. Here, a semiconductor-insulator-semiconductor-type multistacking WSe/graphene/-BN/MoS vdW heterostructure is demonstrated to realize an enhanced self-powered photodetector with a high on-off current ratio of about 1.2 × 10 and a high photoresponsivity of 3.6 A/W without applying bias, which is the highest photoresponsivity ever reported for self-powered photodetectors. Because of the difference in the Fermi level, a built-in electrical field is formed at the WSe/graphene junction, where the photoexcited electrons and holes can be efficiently separated and the carriers can easily tunnel through the MoS/-BN junction driven by the enhanced potential. Therefore, the enhanced self-powered photodetection is attributable to highly efficient carrier tunneling through large -BN electron barriers. By comparison, when the stacking sequence is changed to make WSe/MoS p-n heterojunctions lay on graphene/-BN, the self-powered photocurrent is still generated because of the type-II band alignment, which exhibits lower but still relevant values with a light on/off ratio of ∼8 × 10 and a photoresponsivity of ∼2.39 A/W. The efficient enhancement demonstrates that multistacking heterostructures significantly elevate the performance of self-powered photodetectors, providing a feasible route to develop high-performance self-powered optoelectronic devices and extend their applications in integrated optoelectronic systems.
层状范德华（vdW）异质结构独特的光电特性为高性能光电探测器带来了令人兴奋的机遇。自驱动光电探测器对于降低功耗和最小化器件尺寸是很有必要的。在此，展示了一种半导体-绝缘体-半导体型多层堆叠的WSe/石墨烯/-BN/MoS vdW异质结构，以实现一种增强的自供电光电探测器，其具有约1.2×10的高开/关电流比和3.6 A/W的高光响应度，且无需施加偏压，这是自供电光电探测器有史以来报道的最高光响应度。由于费米能级的差异，在WSe/石墨烯结处形成了一个内建电场，光激发的电子和空穴在该结处能够被有效地分离，并且载流子能够在增强的电势驱动下轻松地隧穿MoS/-BN结。因此，增强的自供电光电探测归因于通过大的-BN电子势垒的高效载流子隧穿。相比之下，当堆叠顺序改变以使WSe/MoS p-n异质结位于石墨烯/-BN上时，由于II型能带排列仍会产生自供电光电流，其开/关比约为8×10，光响应度约为2.39 A/W，数值较低但仍相关。这种有效的增强表明多层堆叠异质结构显著提升了自供电光电探测器的性能，为开发高性能自供电光电器件并扩展其在集成光电子系统中的应用提供了一条可行的途径。
