Enhanced wavelength-selective photoresponsivity with a MoS 2 bilayer grown conformally on a patterned sapphire substrate

Sung Wen Huang Chen, Sheng Wen Wang, Kuo Bin Hong, Henry Medin, Chieh Han Chung, Chun Chia Wu, Teng Yu Su, Fang I. Lai, Po Tsung Lee, Shou Yi Kuo*, Hao Chung Kuo, Yu Lun Chueh

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

8 Scopus citations

Abstract

In the present study, novel MoS 2 bilayers with 3D structures were considered for their application as wavelength-sensitive photodetectors. Using e-gun deposition and a CVD process, MoS 2 bilayers can be grown conformally on a patterned (cones or pyramids) sapphire substrate without any wrinkles on the 2D film. After the sulfurization process, the MoS 2 bilayer is subjected to a local strain in the patterns and its band gap gets enlarged due to the strain. This phenomenon is beneficial for photo-devices to enable the collection of the photocurrent. Measurements revealed a broadband enhancement of the MoS 2 -based photodetector with a patterned array in terms of both absorption and photocurrent. It is noteworthy that a cone-patterned sapphire substrate (CPSS) is able to generate more photocurrent when illuminated under blue light illumination, whereas the pyramid-patterned sapphire substrate (PPSS) performs best under green and red light illumination. Simulations of the electric field distributions for MoS 2 coatings on different substrates, based on 3D models, revealed that the sensitivity of the MoS 2 -based photodetector can be greatly enhanced by the light-scattering effect.

Original languageEnglish
Pages (from-to)1622-1629
Number of pages8
JournalJournal of Materials Chemistry C
Volume7
Issue number6
DOIs
StatePublished - 2019

Bibliographical note

Publisher Copyright:
© The Royal Society of Chemistry.

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