THERMOELECTRIC PROPERTIES OF INDIUM SESQUISELENIDE SINGLE-CRYSTALS

Single crystals of delta-In2Se3 were prepared in the solid state labor atory at Qena-Egypt, by means of Bridgman technique. The temperature d ependence of the thermal e.m.f. alpha in the temperature range from 20 5 K up to 360 K of In2Se, was studied. The delta-phase In2Se3 sample a ppeared to be n-type. The ratio of the electron and hole mobilities ar e found to be mu(n)/mu(p) = 1.378. The effective masses of charge carr iers are m(p) = 1.3 x 10(-30), m(n)* = 8.27 x 10(-31) kg for holes an d electrons, respectively. The diffusion coefficient was estimated to be D(n) = 3.37 cm2/s and D(p) = 2.45 cm2/s for both electrons and hole s, respectively. The mean free time between collision can be deduced t o be tau(n) = 70 x 10(-16) s and tau(p) = 8 x 10(-14) s for both elect rons and holes. The diffusion length of the electrons and holes are fo und to be L(n) = 1.5 x 10(-7) cm and L(p) = 4.4 x 10(-7) CM.