Hole mobility and diffusion coefficient in strained and relaxed doped GexSi1-x alloys

We have calculated the hole mobility and diffusion coefficient in relaxed a nd strained GexSi1-x alloys grown on [001] Si, taking into account the dera iled valence band structure. The acoustic phonon, non-polar optical phonon, alloy as well as ionized impurity scattering are included. Results are rep orted for Ge fractions varying from 0 to 100 percent, for lattice temperatu res between 100 K and 500 Kand the doping concentration varies between 10(1 3)-10(20) cm(-3). Adopted valence band structures rely on the k . p perturb ation theory and include heavy, light and spin split-off bands. The calcula tions show that the light hole contribution to the total mobility can be do minant even if the corresponding band population is small. This is due to t he small effective mass of the light hole. Calculations also show that the strained mobility components are significantly larger than the relaxed mobi lity components. The diffusion coefficient has a behavior similar to the to tal hole mobility.