[en] The mobilities of charge carriers in boron-doped diamond at low temperatures are estimated by numerically solving the Boltzmann equation for a steady-state nonequilibrium velocity distribution function of the carriers with allowance for their scattering by phonons. Estimates show that, at temperatures of up to 100 K, charge carriers with a negative mobility exist over a fairly broad (on the order of 100 K) range of their energies. In the steady-state case, the absolute mobility integrated over the distribution function turns out to be positive, but there are grounds to suppose that, in the case of an unsteady pulsed source of charge carriers, it may become negative.

[en] The discrepancies between the quasi-elastic and inelastic approaches to the calculation of the electron and hole mobilities in diamond at low temperatures when the carrier scattering from acoustic phonons becomes significantly inelastic have been numerically estimated. The calculations showed that the mobility described by a close-to-equilibrium distribution function differs several times from that obtained within the quasi-elastic approach even at 20 K. The results obtained are important for interpreting the low-temperature electrical experiments on high-purity diamond single crystals.

[en] We consider the negative conductivity of electrons in semiconductors excited by a picosecond laser pulse at low temperatures, due to the inelastic electron-phonon collisions. For the first time, the dependence of the deformation potential on the phonon wave number is taken into account. This dependence significantly changes the region of negative electron conductivity as a function of the phonon temperature