First-principle computation of relaxation times in semiconductors for low and high electric fields

Abstract — In this paper we present a method to compute exact relaxation times for any moments of the Boltzmann equation. The method is valid for any electric field and is particularly useful in the case of vanishingly small field intensities. After a theoretical explanation, the method is applied to a full-band model for electrons and holes in silicon. A strong dependence of the relaxation times on the doping concentration is shown, which is in contradictions to popular beliefs. I