Impurity levels and electron scattering mechanisms in bismuth sulfide have been investigated by means of resistivity and Hall-effect measurements in the 30–500-K temperature range. Lattice scattering is predominant in this range and the temperature dependence of the electron mobility, in the crystallographic directions a and c, has been quantitatively interpreted through Fivaz-Schmid and Brooks-Herring models for homopolar optical phonon and ionized impurities scattering, respectively, yielding the energy of the phonon mode (ħω=14 meV) and the electron-phonon coupling constant ($g^2$≳0.4). The density-of-states effective mass in the conduction band has also been determined from Seebeck-effect measurements at room temperature.

• Received 9 December 1986

DOI:https://doi.org/10.1103/PhysRevB.35.9586