Mobility of Charge Carriers in Semiconducting Layer Structures

The electrical resistivities and the Hall constants of the compound semiconductors GaSe, MoS₂, MoSe₂, and WSe₂, which crystallize in layer structures, have been measured at temperatures ranging from 100 to 700^. The Hall mobilities derived from these measurements are all of the order of 100 cm^2/V sec at room temperature, and they exhibit a temperature dependence of the form (T{{T₀}) }^-n, where n=2. 1 for GaSe, n=2. 6 for MoS₂, and n=2. 4 for MoSe₂ and WSe₂. A short-range interaction is discussed which couples the charge carriers in highly anisotropic layer structures to the nonpolar optical lattice modes. The relatively low room-temperature mobilities as well as the high values of the exponents n are explained in terms of the proposed interaction.