Fluorine, chlorine, and gallium co-doped zinc oxide transparent conductive films fabricated using the sol-gel spin method
Liwei Che, Jianmin Song, Jinzheng Yang, Xiaoyang Chen, Junjie Li, Nan Zhang, Shaopeng Yang, Yanfeng Wang
Abstract
Transparent conductive films (TCFs) are crucial components of solar cells. In this study, F, Cl, and Ga co-doped ZnO (FCGZO) TCFs were deposited onto a glass substrate using the sol-gel spin-coating method and rapid thermal annealing. The effects of F-doping content on the structural, morphological, electrical, and optical properties of FCGZO films were examined by XRD, TEM, FE-SEM, PL spectroscopy, XPS, Hall effects testing, and UV–vis–NIR spectroscopy. All prepared ZnO films exhibited a hexagonal wurtzite structure and preferentially grew along the c axis perpendicular to the substrate. Changes in the doping concentration of F changed the interplanar crystal spacing and O vacancies in the film. At a doping ratio of 2% (in mole), the F, Cl, and Ga co-doped ZnO film exhibited the best photoelectric performance, with a carrier concentration of 2.62 × 1020 cm−3, mobility of 14.56 cm2/(V·s), and resistivity of 1.64 × 10−3 Ω·cm. The average transmittance (AT) in the 380–1 600 nm region nearly 90% with air as the reference, and the optical band gap was 3.52 eV.