Monte Carlo study of strain effect on high field electron transport in InAs and InSb

We calculate the unstrained and the strained band structures of InAs and InSb by means of the empirical pseudopotential method. The impact ionization threshold energy, E_th, is calculated while keeping the energy and momentum conservation. Then the electron transport in the unstrained and the strained InAs and InSb is investigated by using the Monte Carlo (MC) method. In both InAs and InSb, the average electron velocity, v_d, increases monotonically with the electric field strength, f. The tensile strain makes the low field electron mobility, μ, higher, and vice versa, which is resulted from the dependence of the effective mass in the Γ valley, m_||*(Γ), on the strain. At the high f, many electrons are restricted within the bottom of the Γ valley because of losing most of their energy by the impact ionization, which results in keeping v_d large at the high f. The tensile strain makes E_th smaller and then the impact ionization coefficient, α, larger, and vice versa. Consequently, v_d at the high f becomes larger under the tensile strain and smaller under the compressive strain.