Optical and electrical properties of as-grown single crystalline PbTe

Single crystal of PbTe is grown by the simple vertical Bridgman method by using high purity Pb and Te as source materials. Cone angle of the ampoule is optimized to obtain a preferred shape of the ingot. It is observed that the growth occurred in 〈2 2 0〉 direction. XRD analysis reveals the formation of rock salt structure with lattice constant 6.463 nm. Crystals were p-type with resitivity ranging from 3.97×10−3 to 4.07×10−3 Ω-cm. At room temperature, hole concentration is found to be ∼1018 cm−3 throughout the crystal length and it is almost constant in the temperature range 130–300 K. At 300 K, the mobility is found to be in the range 842–856 cm2/V-s, lowest being at the higher end of the crystal. The indirect optical band gap and the corresponding absorption coefficients are determined by using FTIR spectrum.