Percolation Description of Charge Transport in Amorphous Oxide Semiconductors: Band Conduction Dominated by Disorder

Amorphous oxide semiconductors, such as InGaZnO (IGZO) materials, are distinguished in the broad class of disordered semiconductors due to high values of charge carrier mobility that makes IGZOs unique for various device applications. In spite of numerous experimental and theoretical studies, the charge transport mechanism in IGZOs was, for a long period, a matter of controversial debates. Only recently, a comprehensive theory of charge transport in IGZOs has been developed based on the percolation theory. Our chapter is dedicated to a detailed description of this approach. Theoretical results are compared to experimental data revealing parameters of disorder potential in IGZO materials.