Carrier scattering mechanisms in P-type indium selenide

Carrier scattering mechanisms in p-indium selenide are investigated by means of the temperature dependence of the Hall mobility (160–500 K) and thermopower (200–300 K). An anomalous behaviour of the Hall voltage, which changes sign below 215 K, is interpreted through the existence of planar aggregates of ionized shallow donor impurities that create potential wells behaving as deep donors and in which a low concentration of two-dimensional free electrons can exist. This fact is taken into account through equations for two-carrier Hall effect. Holes are found to be predominantly scattered by anA ₁ homopolar phonon with an energy of 27.8 meV. From thermopower results, the density of states effective mass in the valence band is determined,m _dv ^* =(1.5±0.2)m ₀.