OPTICAL AND ELECTRICAL-PROPERTIES OF AMORPHOUS SB-SN-O THIN-FILMS

The physical properties of tin oxide thin films containing Sb (Sb-Sn-O ) have been investigated. The films were prepared by spray pyrolysis a t a temperature of 350 degrees C. While the undoped tin oxide (SnO2) t hin film is polycrystalline, the Sb-Sn-O thin films are amorphous. All the films in this study have absorption edges at a wavelength of arou nd 300 nm and are transparent in the wavelength range 400-2600 nn. An explanation is given as to why the amorphous Sb-Sn-O thin films retain transparency although polycrystalline Sb-Sn-O thin films prepared at 500 degrees C are deeply coloured as reported by Kojima et al. in 1993 . The resistivity of the undoped film is 0.23 Omega cm and the additio n of Sb causes the resistivity to rise significantly. From the tempera ture dependence of the film resistivity, a change in the electronic co nduction is found; in the undoped polycrystalline film the electron tr ansport mechanism is band conduction while in the amorphous Sb-Sn-O fi lms it is variable-range hopping.