S. Pal et Dn. Bose, GROWTH, CHARACTERIZATION AND ELECTRICAL ANISOTROPY IN LAYERED CHALCOGENIDES GATE AND INTE, Solid state communications, 97(8), 1996, pp. 725-729
GaTe and InTe are III-VI semiconductors with layered structures which
have large anisotropy in electrical properties. Thermopower, resistivi
ty and Hall effect have been studied in orthogonal directions in high
quality single crystals grown by the Bridgman technique. The hole effe
ctive masses parallel and perpendicular to the layer plane were thus d
etermined to be 0.46m(0) and 0.995m(0), respectively for GaTe and 0.12
5 m(0) and 0.765 m(0) for InTe. The carrier activation energies and ho
le mobilities were also anisotropic. Optical phonon scattering was dom
inant for GaTe with mu alpha T--n with n = 1.85-2.05 and 3.3-3.4 respe
ctively along and perpendicular to the layer planes. InTe with higher
carrier concentrations showed mu alpha T-m, characteristic of ionised
impurity scattering with m = +1.43 in both directions. The optical ban
d-gaps and anisotropy of the dielectric constants have also been measu
red.