Semiconducting Properties of Chromium Disilicide

The electrical resistivities, Hall coefficients and thermoelectric powers of undoped, Si-doped and Mn-modified CrSi 2 crystals have been measured over the temperature range from 90°K to 1100°K. The undoped crystal is a p -type semiconductor with the hole concentration of about 4×10 20 /cm 3 . The hole concentration is decreased by doping silicon or manganese. Manganese atoms act as donors. Specimens heavily doped with manganese are n -type at low temperatures and change to p -type at high temperatures. Analysis of the experimental results leads to the following conclusions: (1) the forbidden energy gap=0.35 eV, (2) the ratio of the electron mobility to the hole mobility≃0.01 and (3) the density of state effective mass of electrons≃7 m 0 and that of holes≃5 m 0 . Assuming that the effective masses and the mobility ratio do not vary with temperature, the temperature dependence of the thermoelectric powers of the undoped and doped crystals can be explained satisfactorily.