Electrical properties of hot-pressed germanium-silicon-boron alloys

Room-temperature electrical resistivity, Hall mobility and Seebeck coefficient measurements on relatively-low-density, hot-pressed, boron-doped Ge 20 Si 80 alloys are reported as functions of 1/R H e in the range 2*10 19 -3.4*10 20 cm -3 . The temperature variations of resistivity and Seebeck coefficient are reported over the temperature range 300-1200K and of 1/R H e and the Hall mobility over the range 300-950K. Within experimental error the absolute values and 1/R H e dependence of the Seebeck coefficients are indistinguishable from single-crystal values. Substantial reductions in carrier mobility accompany the hot-pressing method of preparation, although the reduction is not solely due to porosity effects. A simple mixed scattering model is employed in analysing the electrical data and the conclusion reached that assigning a Hall factor of unity leads to an overestimation in carrier concentration by between 30 and 40%.