Abstract: A variational method and a memory function approach are adopted to investigate electronic mobility and pressure effect in quasi-two-dimensional heterojunction systems by considering optical phonon modes (including bulk longitudinal optical(LO) phonons and interface optical(IO) phonons) and a realistic heterojunction potential model, which includes the influences of finite potential barrier and energy band bending.Meanwhile,the tunnelling of electrons into the barrier is taken into account.A numerical calculation is performed for the Al_xGa_1-xAs/GaAs heterojunctions.The results show that electron mobility obviously decreases as the temperature and pressure incrense;the contribution to electron mobility from IO phonon scattering under pressure becomes more obvious than that from LO phonon scattering.Under pressure,the effect of IO phonon scattering cannot be neglected in further works.

Key words: heterojunction, electronic mobility, pressure effect