Enhanced photoresponse in MoTe2 photodetectors with asymmetric graphene contacts

Wei, Xia; Yan, Faguang; Lv, Quanshan; Zhu, Wenkai; Hu, Ce; Patane, Amalia; Wang, Kaiyou

Abstract

Atomically thin two dimensional (2D) materials are promising candidates for miniaturized high-performance optoelectronic devices. Here, we report on multilayer MoTe2 photodetectors contacted with asymmetric electrodes based on n- and p-type graphene layers. The asymmetry in the graphene contacts creates a large (Ebi ~100 kV cm-1) built-in electric field across the short (l = 15 nm) MoTe2 channel, causing a high and broad (? = 400 to 1400 nm) photoresponse even without any externally applied voltage. Spatially resolved photovoltage maps reveal an enhanced photoresponse and larger built-in electric field in regions of the MoTe2 layer between the two graphene contacts. Furthermore, a fast (~10 ?s) photoresponse is achieved in both the photovoltaic and photoconductive operation modes of the junction. Our findings could be extended to other 2D materials and offer prospects for the implementation of asymmetric graphene contacts in future low-power optoelectronic applications.

Citation

Wei, X., Yan, F., Lv, Q., Zhu, W., Hu, C., Patane, A., & Wang, K. (2019). Enhanced photoresponse in MoTe2 photodetectors with asymmetric graphene contacts. Advanced Optical Materials, 7(12), https://doi.org/10.1002/adom.201900190

• Journal Article Type: Article
• Acceptance Date: Mar 18, 2019
• Online Publication Date: Apr 16, 2019
• Publication Date: Jun 18, 2019
• Deposit Date: Mar 19, 2019
• Publicly Available Date: Apr 17, 2020
• Journal: Advanced Optical Materials
• Electronic ISSN: 2195-1071
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 12
• Article Number: 1900190
• DOI: https://doi.org/10.1002/adom.201900190
• Keywords: Asymmetric graphene contacts; MoTe2; van der Waals heterostructure; Built-in electric filed; Enhanced photoresponse
• Public URL: https://nottingham-repository.worktribe.com/output/1665718
• Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/adom.201900190
• Additional Information: This is the peer reviewed version of the following article: Wei, X., Yan, F., Lv, Q., Zhu, W., Hu, C., Patanè, A., Wang, K., Enhanced Photoresponse in MoTe2 Photodetectors with Asymmetric Graphene Contacts. Advanced Optical Materials 2019, 1900190. , which has been published in final form at https://doi.org/10.1002/adom.201900190 . This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.