Comprehensive optimization of electrical and optical properties for ATO films prepared by pulsed laser deposition

Abstract

Antimony doped tin oxide (ATO) thin films have been prepared by pulsed laser deposition (PLD) method. The intrinsic effect of Sb dopant, including the Sb content, transition degree between Sb3+ and Sb5+ and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated. It is suggested that the transition degree of Sb3+ towards Sb5+ (Sb5+/Sb3+ ratio) is determined by Sb content. When the Sb content is increased to 12 at%, the Sb5+/Sb3+ ratio reaches the highest value of 2.05, corresponding to the resistivity of 2.70×10-3 Ω·cm. Meanwhile, the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%, corresponding to the highest average optical transmittance of 92%. Comprehensively considering the combination of electrical and optical properties, the ATO thin films deposited with Sb content of 12 at% exhibit the best properties with the highest “figure of merit” of 3.85×10-3 Ω-1. Finally, an antimony selenide (Sb2Se3) heterojunction solar cell prototype with the ATO thin film as the anode has been prepared, and a power conversion efficiency of 0.83% has been achieved.