Impact of Dielectric Environment and Thickness on MoS₂ CVD Growth

In order to explore the direct growth of MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> on different dielectrics for scaled transistors fabrication, a theoretical and experimental investigation of the adsorption properties of MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> on different dielectrics are conducted. In this work, we observe that the dielectric environment and thickness both could impact MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> chemical vapor deposition (CVD). MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> shows a lower absorption energy (E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf>) on amorphous HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> than amorphous SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, which is also confirmed by higher nucleation densities and larger surface coverage of MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> on HfO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> during the same CVD process. Notably, for the first time we find thinner dielectric films could prompt the lateral growth of monolayer MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, because thicker dielectric films are easier to become polycrystalline under the MoS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> growth temperature. This study provides a detailed study of dielectric’s impact on Two-dimensional (2D) semiconductor deposition and paves the way for direct integration of 2D-semiconductors based devices on deposition substrates.