Electrode metal species effect on switching characteristics of VDF/TrFE copolymer ultrathin films

The time domain measurements of ferroelectric polarization reversal were conducted for spin-coated ultrathin vinylidene fluoride/trifluoroethylene copolymer films deposited with an Au electrode. It was found that full polarization reversal occurs in 50-330nm-thick films with switching time independent of the film thickness. We conclude that the thinning-induced increase in switching time reported by many researchers is not a general feature of this copolymer but is specific to an Al-electrode-deposited sample. The intrinsic switching characteristics revealed here include the broadening of the switching time distribution with thinning, which is attributed to the nonuniform electric field caused by surface roughness.