Electronic transport studies onSb1−x(SiO2)x films

Abstract

Sb1−x(SiO2)x granular films were prepared by the co-sputtering method with the volume fraction ofSiO2,x, ranging from 0 (i.e. pure Sb) to about 30%. Systematic electronic transportstudies, including resistivity, magnetoresistance, Hall effect and Seebeck effect,were carried out against the temperature, magnetic field and volume fractionx ofSiO2. With the gradualincrease of the SiO2 content, the mean grain size of the Sb decreases, and eventually the film becomesamorphous, as illustrated by the changes of the x-ray diffraction patterns. The temperaturecoefficient of resistivity also changes its sign from positive to negative, indicating asemimetal–semiconductor or insulator transition. Magnetoresistance studies using the weaklocalization theory revealed that the electron dephasing time follows approximately aT−2 law. This behaviour indicates that the electron–phonon (e–ph) scattering still dominatesthe electron dephasing processes in these granular systems with a fair number ofSiO2 inclusions. The Hall coefficient decreases monotonically with temperature and with the volume fractionof SiO2.The giant Hall effect is absent in these granular films. Finally, an interesting but rather complicatedbehaviour of the Seebeck coefficient versus temperature was observed when the volume content ofthe SiO2 exceeded 18%.