Stabilizing Lithium Intercalation in MoS ₂ for 2H‐to‐1T Phase Transition and Low‐Resistance Edge Contacts

Abstract Lithium intercalation in MoS ₂ drives the transformation from its semiconducting 2H to metallic 1T/1T’ phase, allowing the fabrication of low‐resistance edge contacts in transistors and diodes. However, due to the presence of chemically reactive lithium, the properties of the resulting Li _x MoS ₂ are sensitive to processing methods, raising additional concerns about its stability and performance when applied in electronic devices, which have rarely been discussed. Here, the processing method of lithium‐intercalated MoS ₂ in n‐butyllithium solution is investigated for optimal edge contact performance in transistors. The stability of Li _x MoS ₂ when exposed to various solvents, ambient environment (air and vacuum) and thermal stress (from room temperature to 300 °C) is studied in terms of its electrical conductivity and phase ratio. It is found that exposure to water causes immediate degradation of the electrical conductivity of Li _x MoS ₂ , while under thermal stress, irreversible degradation occurs when the temperature exceeds 150 °C. Therefore, avoiding thermal stress during device fabrication is essential. Following this, an optimal procedure is proposed to fabricate low‐resistance 1T‐Li _x MoS ₂ edge contacts, achieving a contact resistance of ≈420 Ω µm, which also displays suppressed defect states in edge‐contacted transistors.