Selective and local flash-annealing for improvement in the contact characteristics of MoS transistors.

The fields of nanoscience and nanotechnology have recently progressed toward the sub-10 nm scale, which is a technology node that requires new materials for various applications owing to the quantum mechanical limitations of silicon. Accordingly, two-dimensional transition-metal dichalcogenides (2D TMDCs) are widely being studied due to their great potential for low-power electronics. Despite these striking advantages, 2D TMDC field-effect transistors have poor mobility due to their high contact resistance and interfacial scattering of defects. To mitigate non-ideal electrical contacts, thermal annealing processes are performed in most cases; however, such processes require expensive and bulky equipment. In this study, a facile approach is proposed for ambient-air and selective annealing, which is performed on a wafer scale between MoS and electrodes through flash lamp irradiation. Flash lamp irradiation promotes excellent photothermal annealing, thus increasing the electrode temperature to >640 K, significantly enhancing the device performance. It was confirmed that the primary cause for the improvement of contact characteristics is the hybridization between Au and MoS and the generation of sulfur vacancies in MoS, supported by surface element analysis and optical measurements.