Augmented Quantum Yield of a 2D Monolayer Photodetector by Surface Plasmon Coupling

• Published in: Nano letters 2018-04, Vol.18 (4), p.2316-2323
• Main Authors: Bang, Seungho, Duong, Ngoc Thanh, Lee, Jubok, Cho, Yoo Hyun, Oh, Hye Min, Kim, Hyun, Yun, Seok Joon, Park, Chulho, Kwon, Min-Ki, Kim, Ja-Yeon, Kim, Jeongyong, Jeong, Mun Seok
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.7b05060

Monolayer (1L) transition metal dichalcogenides (TMDCs) are promising materials for nanoscale optoelectronic devices because of their direct band gap and wide absorption range (ultraviolet to infrared). However, 1L-TMDCs cannot be easily utilized for practical optoelectronic device applications (e.g., photodetectors, solar cells, and light-emitting diodes) because of their extremely low optical quantum yields (QYs). In this investigation, a high-gain 1L-MoS2 photodetector was successfully realized, based on the surface plasmon (SP) of the Ag nanowire (NW) network. Through systematic optical characterization of the hybrid structure consisting of a 1L-MoS2 and the Ag NW network, it was determined that a strong SP and strain relaxation effect influenced a greatly enhanced optical QY. The photoluminescence (PL) emission was drastically increased by a factor of 560, and the main peak was shifted to the neutral exciton of 1L-MoS2. Consequently, the overall photocurrent of the hybrid 1L-MoS2 photodetector was observed to be 250 times better than that of the pristine 1L-MoS2 photodetector. In addition, the photoresponsivity and photodetectivity of the hybrid photodetector were effectively improved by a factor of ∼1000. This study provides a new approach for realizing highly efficient optoelectronic devices based on TMDCs.