Thermoelectric properties of indium sesquiselenide single crystals

Single crystals of δ‐In 2 Se 3 were prepared in the solid state laboratory at Qena‐Egypt, by means of Bridgman technique. The temperature dependence of the thermal e.m.f. α in the temperature range from 205 K up to 360 K of In 2 Se 3 was studied. The δ‐phase In 2 Se 3 sample appeared to be n‐type. The ratio of the electron and hole mobilities are found to be μ n /μ p = 1.378. The effective masses of charge carriers are m   p *= 1.3 × 10 −30 , m   n *= 8.27 × 10 −31 kg for holes and electrons, respectively. The diffusion coefficient was estimated to be D n = 3.37 cm 2 /s and D p = 2.45 cm 2 /s for both electrons and holes, respectively. The mean free time between collision can be deduced to be τ n = 70 × 10 −16 s and τ p = 8 × 10 −14 s for both electrons and holes. The diffusion length of the electrons and holes are found to be L n = 1.5 × 10 −7 cm and L p = 4.4 × 10 −7 cm.