Structure and characteristics of ultrathin indium tin oxide films

A series of indium tin oxide (ITO) thin-films with various thicknesses from 2 to 200 monolayers (ML) have been epitaxially grown on LaAlO3 substrates by laser molecular-beam epitaxy. The measurements of x-ray diffraction, atomic force microscopy, four-probe method, and optical transmittance reveal that the film thickness strongly affects the structural, electrical, and optical properties of ITO thin-films, and the ITO thin-films exist at a critical thickness of metal-insulator transition at about 4-5 ML. The electrical transport property has been discussed with the different conductive models. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3536531]