Structural, electrical and optical properties of sprayed Nd–F codoped ZnO thin films

Undoped ZnO, Nd doped ZnO (NZO), and Nd–F co-doped ZnO (NFZO) thin films were prepared at 350 °C on glass substrates by chemical spray pyrolysis method. 

The effect of cationic and anionic elements (Nd and F) on the structural, optical and electrical properties was studied. X-ray diffraction analysis indicated that all the films were polycrystalline with hexagonal wurtzite crystal structure and that the nature of the doping atom has a strong influence on the preferential growth direction. No sensitive evolution of the band gap is observed upon doping. Photoluminescence measurements showed that all the films have a strong emission band at around 380 nm and that Nd ions are optically activated. In addition, energy transfer from the matrix to Nd³⁺ ions is demonstrated by excitation photoluminescence. Layers with electrical resistivity values as low as 4.0 × 10⁻² Ω cm were obtained.