Effect of precursor solvent on the opto-electrical properties of spin coated transparent conducting ZnO: Ga thin films

Abstract

ZnO: Ga thin films have been prepared by spin coating on glass substrate using solutions of zinc acetate dihydrate and gallium nitrate hydrate precursors in methanol, ethanol and 2-methoxyethanol with mono-ethanolamine as complexing agent to examine the effect of solvent on their opto-electrical characteristics. The selection of the solvent involves factors like toxicity, sol stability and the film properties. Accordingly, ethanol is shown to be suitable for yielding a stable sol to produce low cost 1 at% Ga−ZnO thin films useful for photovoltaic applications. These films exhibit hexagonal structure with (0001) preferred orientation, optical transmittance of ∼75−96% in wavelength range 400−900 nm, electrical resistivity of ∼ 3 × 10−2 Ω-cm and electron mobility of ∼24 cm2/ V. s.