Large Memory Window of van der Waals Heterostructure Devices Based on MOCVD-Grown 2D Layered Ge4Se9

Gichang Noh, Hwayoung Song, Heenang Choi, Mingyu Kim, Jae Hwan Jeong, Yongjoon Lee, Min Yeong Choi, Saeyoung Oh, Min kyung Jo, Dong Yeon Woo, Yooyeon Jo, Eunpyo Park, Eoram Moon, Tae Soo Kim, Hyun Jun Chai, Woong Huh, Chul Ho Lee, Cheol Joo Kim, Heejun Yang, Senugwoo SongHu Young Jeong, Yong Sung Kim, Gwan Hyoung Lee, Jongsun Lim, Chang Gyoun Kim, Taek Mo Chung, Joon Young Kwak, Kibum Kang

Research output: Contribution to journalArticlepeer-review

Abstract

Van der Waals (vdW) heterostructures have drawn much interest over the last decade owing to their absence of dangling bonds and their intriguing low-dimensional properties. The emergence of 2D materials has enabled the achievement of significant progress in both the discovery of physical phenomena and the realization of superior devices. In this work, the group IV metal chalcogenide 2D-layered Ge4Se9 is introduced as a new selection of insulating vdW material. 2D-layered Ge4Se9 is synthesized with a rectangular shape using the metalcorganic chemical vapor deposition system using a liquid germanium precursor at 240 °C. By stacking the Ge4Se9 and MoS2, vdW heterostructure devices are fabricated with a giant memory window of 129 V by sweeping back gate range of ±80 V. The gate-independent decay time reveals that the large hysteresis is induced by the interfacial charge transfer, which originates from the low band offset. Moreover, repeatable conductance changes are observed over the 2250 pulses with low non-linearity values of 0.26 and 0.95 for potentiation and depression curves, respectively. The energy consumption of the MoS2/Ge4Se9 device is about 15 fJ for operating energy and the learning accuracy of image classification reaches 88.3%, which further proves the great potential of artificial synapses.

Original languageEnglish
Article number2204982
JournalAdvanced Materials
Volume34
Issue number41
DOIs
Publication statusPublished - 2022 Oct 13

Keywords

  • charge transfer
  • germanium selenide
  • metal–organic chemical vapor deposition
  • synaptic devices
  • van der Waals heterostructures

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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