High-performance monolayer MoS ₂ photodetector enabled by oxide stress liner using scalable chemical vapor growth method

Abstract

Abstract MoS 2 , as a typical representative of two-dimensional semiconductors, has been explored extensively in applications of optoelectronic devices because of its adjustable bandgap. However, to date, the performance of the fabricated photodetectors has been very sensitive to the surrounding environment owing to the large surface-to-volume ratio. In this work, we report on large-scale, high-performance monolayer MoS 2 photodetectors covered with a 3-nm Al 2 O 3 layer grown by atomic layer deposition. In comparison with the device without the Al 2 O 3 stress liner, both the photocurrent and responsivity are improved by over 10 times under 460-nm light illumination, which is due to the tensile strain induced by the Al 2 O 3 layer. Further characterization demonstrated state-of-the-art performance of the device with a responsivity of 16.103 A W −1 , gain of 191.80, NEP of 7.96 × 10 −15 W Hz −1/2 , and detectivity of 2.73 × 10 10 Jones. Meanwhile, the response rise time of the photodetector also reduced greatly because of the increased electron mobility and reduced surface defects due to the Al 2 O 3 stress liner. Our results demonstrate the potential application of large-scale strained monolayer MoS 2 photodetectors in next-generation imaging systems.