1 research outputs found
Atomic layer deposition of HfO2 on graphene from HfCl4 and H20
Atomic layer deposition of ultrathin HfO2 on unmodified graphene from HfCl4
and H2O was investigated. Surface RMS roughness down to 0.5 nm was obtained for
amorphous, 30 nm thick hafnia film grown at 180 degrees C. HfO2 was deposited
also in a two-step temperature process where the initial growth of about 1 nm
at 170 degrees C was continued up to 10-30 nm at 300 degrees C. This process
yielded uniform, monoclinic HfO2 films with RMS roughness of 1.7 nm for 10-12
nm thick films and 2.5 nm for 30 nm thick films. Raman spectroscopy studies
revealed that the deposition process caused compressive biaxial strain in
graphene whereas no extra defects were generated. An 11 nm thick HfO2 film
deposited onto bilayer graphene reduced the electron mobility by less than 10%
at the Dirac point and by 30-40% far away from it.Comment: 4 figures, accepted by CEJ