Electrical properties of thin bismuth-antimony films. IV. Temperature dependence

Thin film samples of Bi1−xSbx alloys of various thicknesses and compositions have been measured for electrical resistivity, for their coefficient of magnetoresistivity, and for their Hall coefficient in the temperature range 4.2–300 °K. The density and mobility of the charge carriers have been calculated. It is shown that the nonuniform film-potential model used in parts I–III [Sov. J. Low Temp. Phys. 4, 000 (1978); 4, 000 (1978); 4, 000 (1978)] to explain the absence of a semimetal–semiconductor Bi1−xSbx alloys for x = 0.065 and the anomalous size effect in the film conductivity is confirmed by the data obtained in the present study. Because of the increase in charge-carrier density with temperature, the influence of the size effect of the film potential is weakened and the anomalies observed in parts I–III disappear. Various features are observed in the temperature dependences. There is a maximum in the resistivity of very thin films and a minimum in the magnetoresistance coefficient. A general observation is that as the antimony content of the film is increased, the effect is similar to reducing film thickness.