Ion-Induced Phase Changes in 2D MoTe 2 Films for Neuromorphic Synaptic Device Applications

• Published in: ACS nano 2025-01, Vol.19 (2), p.2529-2539
• Main Authors: Rupom, Rifat Hasan, Jung, Moonyoung, Pathak, Anil, Park, Jeongmin, Lee, Eunho, Ju, Hyeon-Ah, Kim, Young-Min, Chyan, Oliver, Kim, Jungkwun, Suh, Dongseok, Choi, Wonbong
• Format: Article
• Language: English
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.4c13915

Two-dimensional molybdenum ditelluride (2D MoTe ) is an interesting material for artificial synapses due to its unique electronic properties and phase tunability in different polymorphs 2H/1T'. However, the growth of stable and large-scale 2D MoTe on a CMOS-compatible Si/SiO substrate remains challenging because of the high growth temperature and impurity-involved transfer process. We developed a large-scale MoTe film on a Si/SiO wafer by simple sputtering followed by lithium-ion intercalation and applied it to artificial synaptic devices. The Al O passivation layer allows us to develop a stable 1T'-MoTe phase by preventing Te segregation caused by the weak bonding between Mo and Te atoms during lithiation. The lithiated MoTe film exhibits excellent synaptic behavior such as long-term potentiation/depression, a high / ratio (≈10 ) at lower sweep voltage, and long-term retention. The in situ Raman analysis along with a systematic microstructural analysis reveals that the intercalated Li ion can provide an efficient pathway for conducting filament formation.