Rapid and large-scale synthesis of MoS₂ via ultraviolet laser-assisted technology for photodetector applications

Two-dimensional transition metal dichalcogenide (TMDC) thin films have been extensively employed in microelectronics research. Molybdenum disulfide (MoS₂), as one of prominent candidates of this class, has been applied in photodetectors, integrated electronic devices, gas sensing, and electrochemical catalysis, owing to its extraordinary optoelectronic, chemical, and mechanical properties. Synthesis of MoS₂ crystal film is the key to its application. However, the reported technology revealed several drawbacks, containing limited surface area, prolonged high-temperature environment, and unsatisfying crystallinity. In order to enhance the convenience of MoS₂ applications, there is a pressing need for optimized fabrication technology, which could be quicker, with a large area, with adequate crystallinity and heat-saving. In this work, we presented an ultraviolet laser-assisted synthesis technology, accomplishing rapid growth (with the growth rate of about 40 um s^-1) of centimeter-scale MoS₂ films at room temperature. To achieve this, we self-assembled a displaceable reaction chamber system, coupled with krypton fluoride ultraviolet pulse laser. The laser motion speed and trajectory could be customized in the software, allowing the maskless patterning of crystal films. As application, we exhibited a photodetector with the integration of synthesized MoS₂ and lead sulfide colloidal quantum dots (PbS CQDs), displaying broadband photodetection from ultraviolet, visible to near-infrared spectrum (365 ~ 1550 nm), with the detectivity of 10⁹ ~ 10¹⁰ Jones, and the rising time of 0.2 ~ 0.3 s. This work not only demonstrated a high-process-efficiency synthesis of TMDC materials, but also has opened up new opportunities for ultraviolet laser used in optoelectronics.