Chemically stabilized epitaxial wurtzite-BN thin film.

We report on the chemically stabilized epitaxial w -BN thin film grown on c -plane sapphire by pulsed laser deposition under slow kinetic condition. Traces of no other allotropes such as cubic ( c ) or hexagonal ( h ) BN phases are present. Sapphire substrate plays a significant role in stabilizing the metastable w -BN from h -BN target under unusual PLD growth condition involving low temperature and pressure and is explained based on density functional theory calculation. The hardness and the elastic modulus of the w -BN film are 37 & 339 GPa, respectively measured by indentation along <0001> direction. The results are extremely promising in advancing the microelectronic and mechanical tooling industry. [ABSTRACT FROM AUTHOR]