INTRINSIC TRANSPORT-PROPERTIES OF INSE STUDIED BY MILLIMETER AND SUBMILLIMETER SPECTROSCOPY

The d.c. and a.c. (2-17 cm(-1)) conductivities of InSe single crystals were measured for temperatures from 4.2 to 300 K. In the frequency ra nge above 5 cm(-1) for the polarization E perpendicular to c, the subm illimeter response of InSe is determined by free charge carriers, whil e at lower frequencies and in the d.c. limit additional effects of loc alization on potential barriers caused by imperfections of the crystal are observed. The average localization radius is evaluated. On the ba sis of our submillimeter data the ''intrinsic'' transport properties o f charge carriers are determined, such as the mobility, the scattering rate, the concentration and the plasma frequency. (C) 1998 Elsevier S cience Ltd.