Characterization of spray pyrolytically deposited high mobility praseodymium doped CdO thin films

Praseodymium (Pr) doped CdO thin films with high transparency and high mobility were deposited, using a homemade spray pyrolysis setup, on micro-slide glass substrates preheated at 300 °C. Polycrystalline nature and Cd-O bond vibration of deposited films were confirmed by X-ray diffraction, micro-Raman and Fourier transform infrared spectroscopy analyses. The oxidation state of Cd2+, O2−, and Pr3+ was confirmed by X-ray photoelectron spectroscopy analysis. The highest average particle size (92 nm-FESEM) and high RMS (13.48 nm-AFM) values are obtained for 0.50 wt% Pr doped CdO thin film. The optical band gap is varied between 2.38 eV and 2.52 eV, depending on the Pr doping concentration. Photoluminescence spectra revealed that Pr doped CdO thin film exhibits strong green emission at 582 nm. High mobility (82 cm2/V s), high charge carrier concentration (2.19×1020 cm−3) and high transmittance (83%) were observed for 0.50 wt% Pr doped CdO film. A high figure of merit (9.79×10−3 Ω−1) was obtained for 0.50 wt% Pr doped CdO thin films. The mechanism behind the above results is discussed in detail in this paper.