Shen Tao, Li Feng, Zhang Zhenyun, Xu Lei, Qi Junjie
School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China.
International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, People's Republic of China.
ACS Appl Mater Interfaces. 2020 Dec 9;12(49):54927-54935. doi: 10.1021/acsami.0c14161. Epub 2020 Nov 25.
Monolayer MoS, a direct bandgap transition metal dichalcogenide (TMD), has attracted worldwide attention in electronics and optoelectronics. However, the performance of photodetectors based on monolayer MoS is restricted to a weak optical absorption, narrow absorption range, and persistent photoconductance. Herein, benefiting from an easy solution process, high light absorption coefficient, and wide absorption range, environment-friendly CuInSe quantum dots (QDs) are hybridized with monolayer MoS for high-performance broadband photodetectors. Owing to the favorable type-II energy band alignment of MoS/CuInSe-QDs, the hybrid photodetector exhibits a broadband photoresponse from the ultraviolet to near-infrared region, with an ultrahigh photoresponsivity of 74.8 A/W at 1064 nm, and compared with those of the pristine MoS device, the photoresponsivity and specific detectivity in the ultraviolet-visible region were enhanced by about 30 and 20 times, respectively. Furthermore, the formed depletion region at the MoS/CuInSe-QDs interface can significantly increase the photoresponse speed, and the accumulated holes in the QD side induce a strong photogating effect to improve the photoresponsive characteristics of the hybrid photodetector. Our work opens up opportunities for fabricating high-performance monolayer TMD-based broadband photodetectors.
单层二硫化钼（MoS）是一种直接带隙过渡金属硫族化合物（TMD），在电子学和光电子学领域引起了全球关注。然而，基于单层MoS的光电探测器的性能受到弱光吸收、窄吸收范围和持续光电导的限制。在此，得益于简单的溶液法、高光吸收系数和宽吸收范围，环境友好的铜铟硒量子点（QDs）与单层MoS杂交，用于制造高性能宽带光电探测器。由于MoS/CuInSe-QDs具有良好的II型能带排列，混合光电探测器在紫外到近红外区域表现出宽带光响应，在1064nm处具有74.8A/W的超高光响应率，与原始MoS器件相比，在紫外-可见光区域的光响应率和比探测率分别提高了约30倍和20倍。此外，在MoS/CuInSe-QDs界面形成的耗尽区可以显著提高光响应速度，量子点一侧积累的空穴会产生强烈的光门效应，从而改善混合光电探测器的光响应特性。我们的工作为制造基于单层TMD的高性能宽带光电探测器开辟了机会。
