Synthesis, structural and field emission properties of multiwall carbon nanotube-graphene-like nanocarbon hybrid films grown by microwave plasma enhanced chemical vapor deposition

Multiwall carbon nanotube (MWCNT)-graphene-like nanocarbon hybrid films were directly deposited on nickel substrate without any pre-treatment in a single-step by microwave plasma enhanced chemical vapor deposition (MW PECVD) technique at 600 °C. The effects of hydrogen partial pressure on the growth of MWCNT-graphene-like nanocarbon hybrid films and their structural, morphological and field emission properties were investigated. High resolution scanning electron microscope revealed MWCNT structure. High resolution transmission electron microscope images and Raman spectra revealed graphene-like nanocarbon film. Raman spectra showed 2D, G, D and D + G peaks at approximately 2690, 1590, 1350 and 2930 cm⁻¹, respectively. The minimum threshold field for electron emission was found to be 3.6 V/μm corresponding to 1 μA/cm² current density for the MWCNT-graphene-like nanocarbon hybrid film deposited at 20 Torr pressure whereas the maximum current density of 0.12 mA/cm² and field enhancement factor of ∼3356 was obtained for the sample deposited at 5 Torr pressure. - Highlights: • MWCNT-graphene-like nanocarbon hybrid films were synthesized by MWPECVD technique. • Effect of pressure on the structural and field emission properties has been studied. • FESEM revealed MWCNT and HRTEM revealed graphene-like nanocarbon film structure. • Minimum E_T = 3.6 V/μm with β = 3164 has been obtained in the film deposited at 20 Torr. • Maximum J = 0.12 mA/cm² with β = 3356 has been obtained in the film deposited at 5 Torr