THERMOELECTRIC PROPERTIES OF INDIUM SESQUISELENIDE SINGLE-CRYSTALS

Single crystals of delta-In2Se3 were prepared in the solid state laboratory at Qena-Egypt, by means of Bridgman technique. The temperature dependence of the thermal e.m.f. alpha in the temperature range from 205 K up to 360 K of In2Se, was studied. The delta-phase In2Se3 sample appeared to be n-type. The ratio of the electron and hole mobilities are found to be mu(n)/mu(p) = 1.378. The effective masses of charge carriers are m(p)* = 1.3 x 10(-30), m(n)* = 8.27 x 10(-31) kg for holes and 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 holes, respectively. The mean free time between collision can be deduced to be tau(n) = 70 x 10(-16) s and tau(p) = 8 x 10(-14) s for both electrons and holes. The diffusion length of the electrons and holes are found to be L(n) = 1.5 x 10(-7) cm and L(p) = 4.4 x 10(-7) CM.