Superior Plasmonic Photodetectors Based on Au@MoS 2 Core-Shell Heterostructures

• Published in: ACS nano Vol. 11; no. 10; pp. 10321 - 10329
• Main Authors: Li, Yuan, DiStefano, Jennifer G, Murthy, Akshay A, Cain, Jeffrey D, Hanson, Eve D, Li, Qianqian, Castro, Fernando C, Chen, Xinqi, Dravid, Vinayak P
• Format: Journal Article
• Language: English
• Published: United States 24.10.2017
• Subjects: photodetectors; core−shell; heterostructures; Au@MoS2; plasmonic enhancement
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.7b05071

Integrating plasmonic materials into semiconductor media provides a promising approach for applications such as photosensing and solar energy conversion. The resulting structures introduce enhanced light-matter interactions, additional charge trap states, and efficient charge-transfer pathways for light-harvesting devices, especially when an intimate interface is built between the plasmonic nanostructure and semiconductor. Herein, we report the development of plasmonic photodetectors using Au@MoS heterostructures-an Au nanoparticle core that is encapsulated by a CVD-grown multilayer MoS shell, which perfectly realizes the intimate and direct interfacing of Au and MoS . We explored their favorable applications in different types of photosensing devices. The first involves the development of a large-area interdigitated field-effect phototransistor, which shows a photoresponsivity ∼10 times higher than that of planar MoS transistors. The other type of device geometry is a Si-supported Au@MoS heterojunction gateless photodiode. We demonstrated its superior photoresponse and recovery ability, with a photoresponsivity as high as 22.3 A/W, which is beyond the most distinguished values of previously reported similar gateless photodetectors. The improvement of photosensing performance can be a combined result of multiple factors, including enhanced light absorption, creation of more trap states, and, possibly, the formation of interfacial charge-transfer transition, benefiting from the intimate connection of Au and MoS .