(Invited) Memristive Devices based on Two-Dimensional Materials

ECS Meeting Abstracts, vol. MA2021-01, pp. 998

Abstract

Two-dimensional layered materials are emerging as candidates for neuromorphic switches. So far, several different phenomena have been proposed as device switching mechanisms. These include the lateral movement of ions, either in van der Waals gaps [1] or grain boundary mediated [2], phase changes in 2D materials [3], defect mediated resistive switching [4], or vertical ion movement and subsequent modulation of electronic barriers [5]. In this talk, vertically aligned molybdenum disulfide (MoS2) will be discussed as a memristive material that allows ionic transport along its van der Waals gaps. These ions contribute to the electron transport properties across the vertical device structures [6]. In addition, the motion of ions can be used to tune energy barriers at MoS2/semiconductor Schottky junctions [5]. We have identified hydroxyl (OH-) ions that likely originate from catalytic splitting of water molecules in the devices [7]. In addition, vacancies are present in the 2D films that manifest as absorbers for infrared radiation, i.e. wavelengths beyond what is expected from a semiconductor with a bandgap of approximately 1.2 eV [8], [9]. Acknowledgements The authors acknowledge funding by the European Commission in the Horizon 2020 grant agreements 881603 (Graphene Flagship) and 829035 (QUEFORMAL), the German BMBF grant NEUROTEC (16ES1134) and the DFG projects MOSTFLEX (407080863) and ULTIMOS2 (412113712). References [1] X. Zhu, D. Li, X. Liang, and W. D. Lu, “Ionic modulation and ionic coupling effects in MoS 2 devices for neuromorphic computing,” Nat. Mater., vol. 18, no. 2, Art. no. 2, Feb. 2019. [2] V. K. Sangwan et al., “Gate-tunable memristive phenomena mediated by grain boundaries in single-layer MoS2,” Nat. Nanotechnol., vol. 10, no. 5, pp. 403–406, May 2015. [3] F. Zhang et al., “Electric-field induced structural transition in vertical MoTe 2 - and Mo 1–x W x Te 2 -based resistive memories,” Nat. Mater., vol. 18, no. 1, p. 55, Jan. 2019. [4] S. M. Hus et al., “Observation of single-defect memristor in an MoS 2 atomic sheet,” Nat. Nanotechnol., pp. 1–5, Nov. 2020. [5] M. Belete et al., “Nonvolatile Resistive Switching in Nanocrystalline Molybdenum Disulfide with Ion-Based Plasticity,” Adv. Electron. Mater., p. 1900892, 2020. [6] M. Belete et al., “Dielectric Properties and Ion Transport in Layered MoS2 Grown by Vapor-Phase Sulfurization for Potential Applications in Nanoelectronics,” ACS Appl. Nano Mater., vol. 1, no. 11, pp. 6197–6204, Nov. 2018. [7] S. Li et al., “Edge-Enriched 2D MoS2 Thin Films Grown by Chemical Vapor Deposition for Enhanced Catalytic Performance,” ACS Catal., vol. 7, no. 1, pp. 877–886, Jan. 2017. [8] A. Bablich et al., “Few-Layer MoS2/a-Si:H Heterojunction Pin-Photodiodes for Extended Infrared Detection,” ACS Photonics, vol. 6, no. 6, pp. 1372–1378, Jun. 2019. [9] D. S. Schneider et al., “Highly Responsive Flexible Photodetectors Based on MOVPE Grown Uniform Few-Layer MoS2,” ACS Photonics, vol. 7, no. 6, pp. 1388–1395, Jun. 2020.

Authors 1

1. Max C. Lemme corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University