Realization of Eu-doped p-SnO2 thin film by spray pyrolysis deposition

Abstract

We report the fabrication of p-SnO2 thin films by spray pyrolysis deposition using europium (Eu) as an acceptor. Structural and chemical investigations verified that Eu3+ ions were successfully incorporated into the SnO2 crystal by substituting the Sn4+ sites in the lattice. Even though the undoped SnO2 thin film showed n-type properties with a charge carrier concentration of −2.343 × 1018 cm−3, SnO2 showed p-type properties as the Eu was incorporated. In addition, the charge carrier concentration of the Eu-doped SnO2 increased to 9.121 × 1019 cm−3 as the molar content of the Eu source was increased to 0.2 mM. The optical transmittance was not degraded by the Eu doping and was maintained between 70 and 80% in the visible wavelength spectral range, while the optical band gap of the Eu-doped SnO2 increased due to the Burstein-Moss effect. The thin film field-effect transistor fabricated by using the Eu-doped SnO2 showed the typical gate-modulated drain current characteristic of a p-channel transistor with depletion mode. These results demonstrated the effectiveness of Eu as a dopant for p-SnO2.