Impact of Gd-doped on optoelectronic properties of SnO2 thin films synthesized by spin coating method
Harish Sharma Akkera, Yathish Kumar, Paramita Sarkar, Nagaiah Kambhala, G. Srinivas Reddy
Abstract
Pure and various concentrations of Gd-doped SnO 2 thin films were synthesized using a spin coating method on a glass substrate . XRD studies revealed that all the thin films exhibited polycrystalline tetragonal structures with a fundamental orientation peak along the (110) direction. The three main E g , A 1g , and B 2g vibrational modes were identified using Raman spectroscopy . XPS studies determined the oxidation states of Sn, Gd , and O. Pure SnO 2 has an average optical transmittance of 83 % and it reduced significantly with Gd-doping and reached 55 % in the case of a 5-at% Gd-doped film. The optical band gap energy of 4.01 eV was found in pure SnO 2 and decreased with the Gd doping, reaching 3.88 eV in a 5-at% Gd-doped SnO 2 film. The 3 at% Gd: SnO 2 and pure SnO 2 films were shown the lowest sheet resistance ( R sh ) of 33.1 Ω/Sq highest figure of merit (φ) of 2.26 × 10 −3 Ω −1 , respectively among others.