Dielectric screening effects on electron transport in Ga0.51In0.49P/InxGa1-xAs/GaAs quantum wells

The effects of dielectric screening on the two dimensional polar optical ph onon scattering and on electron transport in Ga0.51In0.49P/InxGa1-xAs/GaAs (x=0, 0.15, and 0.25) modulation doped heterostructures and high electron m obility transistors are investigated through the ensemble Monte Carlo techn ique. The two dimensional polar optical phonon scattering rates including a nd excluding dielectric screening effects are calculated using the self-con sistently evaluated electronic states in the quantum well. The calculated s cattering rates are compared in order to see the effects of screening on th e inter- and intra-subband scattering. Screening significantly lowers the i ntra-subband polar optical phonon scattering rates in both lattice matched and pseudomorphic structures. This results in a considerable lowering of th e critical electric field beyond which negative differential resistance is seen. Screening also modifies the dependence of transport properties on the quantum well parameters. The results of the ensemble Monte Carlo simulatio ns of high electron mobility transistors show that the performance of the d evice is considerably underestimated, if screening is not included in the c alculation of the polar optical phonon scattering rates. (C) 2000 American Institute of Physics. [S0021-8979(00)00515-6].