Effect of Sb doping on structural and photoelectric properties of SnO_2 thin films

摘要

Sb-doped SnO_2 (ATO) thin films were synthesized via the sol-gel dip-coating method on glass substrates. The XPS and XRD spectra showed that Sb atoms were successfully incorporated into the SnO_2 lattice and mostly existed in the form of Sb~(5+) (～90%) in 1 at.% ATO thin films annealed in air and further annealed in vacuum. The transmittance spectra revealed that the average transmittance was more than 75% at the wavelength range of 325-700 nm. The average sheet resistance-was 14.05 kΩ/□ in 1 at.% ATO thin films annealing in air and much less than undoped SnO_2. The electric property was better when ATO thin films were further annealing vacuum compared to annealing in air. The average sheet resistance and resistivity of 1 at.% ATO thin films were 2.42 kΩ/□ and 0.035 Ω cm, respectively. The PL showed that electrons transition from a shallow level of V_O to the minimum level of conduction band (CBM) increased with increasing of Sb~(3+) ions. The maximum level of valence band (VBM) and CBM level positions were mainly affected by Sb~(3+) and Sb~(5+) energy levels after air annealing, respectively. The behavior of surface carrier transport was investigated after further vacuum annealing. The CBM-VBM level position mainly was affected by V_O energy level after further vacuum annealing. It was further proved by the Hall carrier concentration and the electrochemical impedance spectroscopy (EIS).