Pulsed laser deposition and optical band gap engineering in multinary transparent conducting oxide thinfilms

Synthesis of ternary and multinary oxide-based films offers the possibility of tuning electrical and optical properties of the existing materials over wide range. Here we report about synthesis and characterization of Zn_1.9Sn_0.9In_0.1Ga_0.1O₄, Zn_1.9Sn_0.9In_0.2O₄, and Zn_1.9Sn_0.9Ga_0.2O₄ grown by a pulsed laser deposition method. These compounds have been synthesized on the base of Zn₂SnO₄ by substituting Zn²⁺ and Sn⁴⁺cations with group-III elements such as In³⁺ and Ga³⁺. The newly synthesized films are shown to possess a very smooth surface with lower RMS components and exhibit dense grown crystallites with homogenous distribution of small grains. Highly textured growth of inverse cubic spinel structured thinfilms along (111) direction is identified from X-ray diffraction studies. Raman analysis provided supplementary evidences for XRD results. Giant increases of the band gap from 3.60 eV to 3.90 eV have been reported by the development of multinary compounds. The electrical features obtained from Van der Pauw Hall measurements show enhanced charge carrier mobility, resistivity and moderate charge carrier concentrations.