Abstract
The authors report the first direct measurement of the electrical anisotropy of ZrS3-xSex compounds. The microwave cavity perturbation technique is used to measure the conductivity and the dielectric constant of these n-type semiconductors along two crystal axes (b and a), for samples covering the entire composition range. The conductivity is dominated by a single activation regime in the 300-500K range and is interpreted in terms of the presence of two donor impurity levels and a compensation varying with composition. The electrical anisotropy between the two directions is found to be relatively small and a 3D electrical behaviour is believed to be associated to these compounds. The composition dependence of the dielectric constant is found to be related to the superposed electronic and lattice contributions and a jump near the x=2 composition may be associated with a possible 1D to 2D structural transition. A ratio of epsilon 1/// epsilon 1 perpendicular to approximately=2 is measured and is attributed to the normal anisotropy associated with non-cubic crystals.