Electromagnetic properties of SiO₂ reinforced with both multi-wall carbon nanotubes and ZnO particles

SiO₂ reinforced with both multi-wall carbon nanotubes (MWCNTs) and ZnO particles was prepared. Owing to the consumption of an amorphous carbon layer on the outer surface of MWCNTs and the generation of oxygen vacancies in ZnO during sintering, the contact resistance between MWCNTs is lowered and a higher concentration of charge carriers is produced in ZnO. The permittivity of the composite is improved by both changes. The composite containing 15 wt% ZnO particles and 3 wt% MWCNTs exhibits a wider effective absorption bandwidth and lower minimum reflection coefficient than both SiO₂ reinforced with 15 wt% ZnO particles and SiO₂ reinforced with 3 wt% MWCNTs.