Sign and Activation Energy of Hall Coefficient for Hopping Conduction in Heavily Al-Doped 4H-Sic

Matsuura H, Nishihata R and Hidaka A

Published on: 2022-05-07

Abstract

Here we investigate the temperature-dependent resistivity  and Hall coefficient  of heavily Al-doped 4H-SiC. The sign of  changes from positive to negative in nearest-neighbor hopping (NNH) conduction and variable-range hopping (VRH) conduction according to Mott’s model, whereas it is positive in band conduction because Al-doped 4H-SiC is a p-type semiconductor. We propose a physical model to explain why  in hopping conduction becomes negative at low temperatures, which is applicable to both NNH and VRH conduction. Moreover, we elucidate the reason why the activation energy of negative  becomes close to that of  in NNH conduction.