Effect of Gamma Irradiation on the Electrical Properties of Extruded Bi_0.85Sb_0.15 Solid Solution Samples Doped with Pb Acceptor Impurities

The effect of gamma irradiation on the electrical properties of extruded Bi_0.85Sb_0.15 solid solution samples doped with 0.001 to 0.05 at % Pb has been studied in the range ~77–300 K. The results suggest that irradiation of the undoped material to a gamma dose of ~1 Mrad produces donor defects and leads to an increase in carrier concentration n and electrical conductivity σ. The radiation-induced donor defects in the material containing 0.001 at % Pb compensate Pb acceptor centers, reducing σ. In the materials containing ≥0.005 at % Pb, conduction electrons are compensated by Pb acceptor centers, so electrons generated by gamma irradiation lead to an increase in σ. A good correlation is observed between the dependences of electrical conductivity σ, thermoelectric power α and Hall coefficient R_H on Pb content and gamma irradiation dose.