Spin Coating: Easy Technique for Thin Films

Spin coating is a well-defined technique of spreading a solution equally across a surface to deposit uniform and homogeneous thin film over the surface of the substrate through an organized precursor or gel employing centripetal force. A gel of precursor inclusive of a specific solute and solvent is placed on the substrate followed by spinning of the substrate at a high speed. Both centripetal force and the surface tension of the precursor lead to the development of a solid thin layer covering owing to the release and vaporization of the gel. The process of spin coating yields a few nanometers to a few microns film thickness with great uniformity. Quick and easy deposit with extremely uniform deposition of diverse nanostructured films is its main advantage over other approaches. For a flat substrate, spin-coating enables the application of a highly uniform layer over a large area with a relatively tunable and reproducible thickness. Spin coating is used to coat inorganic, organic, and inorganic/organic solution mixtures. In this technique, spin speed and fluid viscosity are the only variables that can be altered, rendering spin coating rather robust. This chapter aims to introduce the concept of the spin coating process. In particular, it exposes an introduction, basic principle, theoretical background, literature review, experimental setup, reaction mechanism, influence of the preparative parameters along with the advantages and disadvantages.