Laser‐Assisted Phase Engineering of 2D MoS ₂ for Efficient Solution‐Processed Electronics

Abstract

ABSTRACT Phase engineering of two‐dimensional transition metal dichalcogenides (2D TMDs), such as MoS 2 , offers a powerful route for creating in‐plane metal‐semiconductor heterostructures and engineering low‐resistance contacts in 2D electronics. Conventional strategies typically rely on chemically converting the semiconducting 2H phase into the metallic 1T/1T′ polymorph, a multistep process prone to incomplete phase conversion. Local laser‐induced transition of 1T/1T′ into 2H MoS 2 offers a facile one‐step alternative. However, employing this approach to engineer patterned electronic devices has remained elusive. Here, we demonstrate laser‐assisted 1T′→2H phase patterning in phase‐pure, solution‐processed MoS 2 , revealing the critical effect of irradiation atmosphere on phase transition. Although treatments in both ambient and inert environments produce apparent 2H Raman signatures, only inert‐atmosphere irradiation yields micron‐scale 2H domains within the 1T′ lattice. Leveraging this controlled transition, we fabricate field‐effect transistors with laser‐patterned 1T′–2H–1T′ lateral contacts that exhibit improved charge injection, as evidenced by order‐of‐magnitude higher mobility and I ON / I OFF ratio, reduced hysteresis, and a ∼30% lower effective Schottky barrier height compared with conventional Au‐2H contacts. These findings establish a robust and scalable route for functional laser‐induced phase conversion in MoS 2 and provide a practical strategy for efficient and seamlessly integrated 2D electronic devices and circuits.