Hopping-type charge transport

Hopping occurs between neighboring molecules and the activation energies are small, from 0.12 to 0.15 eV for the hydrocarbons. Fast anions have also been suggested for liquid SFg [180]. Thus several examples of this type of transport for the negative charge exist and the mobilities are comparable. More examples of fast ions are expected to be found in the future. 

Such high concentrations of gap states attached to the valence band essentially affect the electronic charge transport in particular, they are responsible for the p-type character and the very low electrical conductivity. Aside from the electric conductivity in extended band states, a hopping-type conduction must be expected in localized gap states. The electronic properties of boron carbide can be consistently described by a band scheme, which highlights deep energy levels in the band gap (2.09 eV) at 0.065, 0.18, 0.47, 0.77, 0.92 and 1.2 eV (values based on optical measurements), related to the valence band edge. This allows the largely consistent description of all reliable experimental results [537]. 

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