Enhanced electrical and optical properties of single-layered MoS₂ by incorporation of aluminum

Electrical and optical enhancements of single-layer semiconducting materials such as transition metal dichalcogenides have recently been studied to achieve sensitive properties via external treatments, such as the formation of organic/inorganic protecting layers on field-effect transistors (FETs), thermal annealing, and nano-dot doping of sensors and detectors. Here, we propose a new analytical approach to electrical and optical enhancement through a passivation process using atomic layer deposition (ALD), and demonstrate a synthesized MoS₂ monolayer incorporated with Al atoms in an Al₂O₃ passivation layer. The incorporated Al atoms in the MoS₂ monolayer are clearly observed by spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) and TEM-energy-dispersive X-ray spectroscopy results. We demonstrate that the chemically incorporated FETs exhibit highly enhanced mobilities of approximately 3.7 cm²·V^-1·s^-1, forty times greater than that of as-synthesized MoS₂, with a three-fold improvement in the photoluminescence properties.