▎ 摘　　要

Here, we present the theory of the conductivity of a pn junction (pnJ) in a graphene channel, placed on a ferroelectric substrate, caused by the ferroelectric domain wall for the case of the arbitrary current regime: from ballistic to diffusive one. We calculated the ratio of the pnJ conductions for opposite polarities of voltages, applied to source and drain electrodes of the channel, G(+)(total)/G(-)(total), as a function of graphene channel length L, electron mean free path lambda, and ferroelectric substrate permittivity epsilon(f)(33). We have demonstrated that the small values of G(+)(total)/G(-)(total) (0.1 and smaller), which correspond to the efficient graphene pnJ based rectifier, can be obtained for the ferroelectrics with high e(33)(f) >> 100 and for the ratios of L/lambda similar to 1 or smaller. However, for ferroelectrics with extremely high e(33)(f) (relaxor or PbZrxTi1-xO3 with the composition x near the morphotropic phase boundary x = 0.52), the ratio G(+)(total)/G(-)(total) can be essentially smaller than unity for the case of a pronounced diffusive regime of current as well. This makes the ferroelectric substrates with high permittivity excellent candidates for the fabrication of new generation of rectifiers based on the graphene pnJ. The temperature effect on the G(+)(total)/G(-)(total) ratio was studied within the Landau-Ginzburg- Devonshire approach. We have demonstrated that the rectifying properties of the graphene pnJ become better in the vicinity of Curie temperature. However, for the temperatures higher than the Curie temperature, the rectifying effect vanishes due to the ferroelectric polarization disappearance. Published by AIP Publishing.