HALL FACTOR IN STRAINED P-TYPE DOPED SI1-XGEX ALLOY

We have calculated the Hall factor in strained p-type Si1-xGex alloy g rown on (001) Si, taking into account the detailed valence-band struct ure. Acoustic-phonon, nonpolar optical-phonon, alloy, and ionized-impu rity scattering are included. It is demonstrated experimentally that t he Hall factor can be reduced by a factor of 2 when alloying Si with G e. Theoretically we have shown that the Hall factor is significantly r educed because of the nonparabolic and nonspherical effects in the val ence-band structure. The theory explains experimental results very wel l. It is also shown that the low-temperature Hall factor is independen t of scattering mechanisms. It depends only on the energy band structu re.