Intervalley scattering in n type Ge from a Hall effect experiment to high pressures

Abstract

Hall effect measurements on n type Ge to 65 kbar are described. The Hall mobility of electrons through the transfer from (111) to (100) states has been measured and an assessment of the scattering parameters for the different intervalley and intravalley processes has been made following the analysis of Nathan et al. (1961). The Hall mobility of electrons in the (100) valleys is determined as 1020+or-170 cm²V^-1s^-1, the (100) effective mass is estimated to be approximately 50% greater than for n type Si and the (100)-(111) energy sub-band gap is 0.186+or-0.010 eV. Nonequivalent intervalley scattering between the (111) and (100) valleys is shown to reduce the mobility by a factor of two near band cross-over. Results are directly relevant in determining coupling constants between valleys in high electric field calculations, involving (100) and (111) minima, as in InP.