Growth mechanism and optical properties of Ti thin films deposited onto fluorine-doped tin oxide glass substrate

Abstract

In this work, a detailed study of the influence of the thickness on the morphological and optical properties of titanium (Ti) thin films deposited onto rough fluorine-doped tin oxide glass by d.c. magnetron sputtering is carried out. The films were characterized by several methods for composition, crystallinity, morphology, and optical properties. Regardless of the deposition time, all the studied Ti films of 400, 1500, 2000, and 2500 nm in thickness were single crystalline in the α-Ti phase and also very similar to each other with respect to composition. Using the atomic force microscopy (AFM) technique, the authors analyzed the roughness evolution of the Ti films characteristics as a function of the film thickness. By applying the dynamic scaling theory to the AFM images, a steady growth roughness exponent α = 0.72 ± 0.02 and a dynamic growth roughness exponent β = 0.22 ± 0.02 were determined. The value of α and β are consistent with nonlinear growth model incorporating random deposition with surface diffusion. Finally, measuring the reflection spectra of the samples by a spectrophotometer in the spectral range of 300–1100 nm allowed us to investigate the optical properties. The authors observed the increments of the reflection of Ti films with thickness, which by employing the effective medium approximation theory showed an increase in thickness followed by an increase in the volume fraction of metal.

Anodic formation of highly ordered TiO2 nanotube arrays on conducting glass substrate: Effect of titanium film thickness

“…24 In our previous paper, 24 we found that the volume fraction of metal increases as the thickness increases and denser films can be created by increasing the film thickness. Influence of Ti film thickness on the morphology of TiO 2 nanotube arrays Titanium films deposited onto FTO glass substrate with varied thicknesses (1.5, 2.0, and 2.5 lm) are used to investigate the thickness effect on the formation, shape, size, and length of TiO 2 nanotube array.…”

Tailoring morphology, structure and photoluminescence properties of anodic TiO2nanotubes

“…As mentioned above, the titanium films with low thickness have a lower density and a greater roughness (Einollahzadeh-Samadi & Dariani, 2015). Increasing porosity and roughness with decreasing titanium film thickness leads to an enhancement of chemical etching assisted by the F À ions, which results in a non-uniform structure with large pores and thereby poor interconnections on the upper layer of the TNT array.…”

“…The first stage is deposition of a high-quality titanium film with good adhesion to the substrate. Usually the deposition is performed via electron-beam evaporation (Butail et al, 2011), direct current (DC) magnetron sputtering (Einollahzadeh-Samadi & Dariani, 2015) or radio frequency sputtering (Tang et al, 2011). Finally, the deposited titanium films are placed into an anodization cell and thermally treated to ensure uniformity of the crystalline TiO 2 nanotubes.…”