Nanostructure and Physical Properties Control of Indium Tin Oxide Films Prepared at Room Temperature through Ion Beam Sputtering Deposition at Oblique Angles

Abstract

In this paper, we report the fabrication of porous and crystalline tin-doped indium oxide (ITO) thin films at room temperature by ion beam sputtering deposition at oblique angles using either argon or xenon ions. Deep insights into these systems are provided by coupling nanostructural (scanning and transmission electron microscopies, X-ray diffraction) and optical (spectroscopic ellipsometry, spectral reflectometry) characterizations. This original approach allows extracting important features of the films (porosity, refractive indexes, in-grain carrier densities, and mobilities) not easy to reach locally by other techniques. We propose a model decomposing the complex film's nanostructure into two layers presenting different electro-optical properties, which are attributed to the shadowing effect, but also to the presence of growth defects and impurities due to the atomic peening. In particular, we demonstrate that ITO films deposited with Xe present a better crystallinity and larger porosity, providing superior in-grain carrier transport and offering more flexibility to design broad-band low-reflectivity surfaces. These results widen the possibilities to engineer transparent and conductive thin films at room temperature with enhanced properties, especially in the near-infrared range where oblique angle deposition allows a reduction of reflectivity even at high doping.

Finite Element Mesh Generation for Nano-scale Modeling of Tilted Columnar Thin Films for Numerical Simulation

“…It is then possible to nanostructure the film by controlling the deposition angle and thus vary its properties. This effect has already been documented for a variety of applications, such as anti-reflect optical films [13], magnetic films [14] or mechanical applications [15].…”

Dye-Sensitized Nonstoichiometric Strontium Titanate Core–Shell Photocathodes for Photoelectrosynthesis Applications

“…HRTEM imaging, Figure f,g, reveals highly crystalline core nanoparticles coated with an amorphous shell layer. The lattice spacing corresponds to (222) planes of In 2 O 3 . − The sharp distinction between the crystalline core and amorphous shell is utilized to measure the thickness of the latter, which is 1.0 ± 0.2 nm. Given the initial Al 2 O 3 layer is 0.8 nm, the STOx layer is an ultrathin ∼0.2 nm.…”

The Impact of the Surface Modification on Tin-Doped Indium Oxide Nanocomposite Properties

“…To provide this space, the distance between slabs needs to be more than the lattice constant of the ITO. Considering the BCC structure, the experimental value for the lattice parameter of the ITO with 10 wt% tin is 10.1288 Å [ 108 , 111 , 112 , 113 ]. Therefore, any distance less than the measured values for the lattice parameter will not provide a realistic interlayer space between slabs.…”