Abstract Bi 2 Se x Te 3− x crystals with various x values were grown by Bridgman method. The electrical conductivity, σ , was found to decrease with increasing Se content. The highest σ of 1.6 × 10 5 S m −1 at room temperature was reached at x = 0.12 with a growth rate of 0.8 mm h −1 . The Seebeck coefficient, S , was less dependent on Se content, all with positive values showing p-type characteristics, and the highest S was measured to be 240 μV K −1 at x = 0.24. The lowest thermal conductivity, κ , was 0.7 W m −1 K −1 at x = 0.36. The electronic part of κ , κ el , showed a decrease with increasing Se content, which implies that the hole concentration as the main carriers was reduced by the addition of Se. The highest dimensionless figure of merit, ZT , at room temperature was 1.2 at x = 0.36, which is attributed to the combination of a rather high electrical conductivity and Seebeck coefficient and low thermal conductivity.