Carbon-nanoparticle-assisted growth of high quality bilayer WS₂ by atmospheric pressure chemical vapor deposition

Two-dimensional (2D) WS₂ offers great prospects for assembling next-generation optoelectronic and electronic devices due to its thickness-dependent optical and electronic properties. However, layer-number-controlled growth of WS₂ is still a challenge up to now. This work presents controlled growth of bilayer WS₂ triangular flakes by carbon-nanoparticle-assisted chemical vapor deposition (CVD) process. The growth mechanism is also proposed. In addition, the field effect transistors (FETs) based on monolayer and bilayer WS₂ are also fabricated and investigated. The bilayer FET displays a mobility of 34 cm²·V^-1·s^-1, much higher than that of the monolayer FET. The high figures of merit make bilayer WS₂ a promising candidate in high-performance electronics and optoelectronics.