Selective and localized laser-anneal effect for high-performance flexible multilayer MoS2 thin-film transistors

We report enhanced performance of multilayer MoS2 field effect transistors (FETs) on flexible plastic substrates with ultra‐short, pulsed‐laser annealed Ti/Au contacts without thermal damage. An analysis of the temperature distribution, based on finite difference methods, enabled understanding of the compatibility of our picosecond laser annealing for flexible PEN substrate with low thermal budget (< 200°C). The reduced contact resistance after laser annealing provided significant improvement in transistor performance including higher peak field‐effect mobility (from 24.84 cm2V‐1s‐1 to 44.84 cm2V‐1s‐1), increased output resistance (0.42 MΩ at Vgs‐Vth= 20 V, three times higher), 6‐fold increase of the self‐gain, and decreased subthreshold swing. Transmission electron microscopy analysis and current‐voltage measurements suggested that the reduced contact resistance is resulted from the decrease of Schottky barrier width at the MoS2‐metal junction. These results demonstrate that the selective contact laser annealing is an attractive technology for fabricating low‐resistivity metal‐semiconductor junctions, providing important implications for the application of high‐performance two‐dimensional semiconductor FETs toward flexible electronics.