Effect of Plasma-Enhanced Atomic Layer Deposition on Oxygen Overabundance and Its Influence on the Morphological, Optical, Structural, and Mechanical Properties of Al-Doped TiO2 Coating

• Published in: Micromachines (Basel) Vol. 12; no. 6; p. 588
• Main Authors: Chiappim, William, Testoni, Giorgio, Miranda, Felipe, Fraga, Mariana, Furlan, Humber, Saravia, David Ardiles, Sobrinho, Argemiro da Silva, Petraconi, Gilberto, Maciel, Homero, Pessoa, Rodrigo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 21.05.2021; MDPI
• Subjects: Aluminum oxide; Atomic layer epitaxy; Atomic properties; Automation; Biosensors; Chemical vapor deposition; Corrosion; Corrosion prevention; Crystal structure; Crystallinity; doping; Fluorescence; Insulators; Mechanical properties; Morphology; nanolaminates; Optical properties; Oxygen; Photovoltaic cells; Plasma; plasma-enhanced atomic layer deposition; Refractivity; Software; Solar cells; Spectrum analysis; superstoichiometry; Surface hardness; Thin films; Titanium dioxide; Brazil; United States > US; Japan
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi12060588

The chemical, structural, morphological, and optical properties of Al-doped TiO2 thin films, called TiO2/Al2O3 nanolaminates, grown by plasma-enhanced atomic layer deposition (PEALD) on p-type Si and commercial SLG glass were discussed. High-quality PEALD TiO2/Al2O3 nanolaminates were produced in the amorphous and crystalline phases. All crystalline nanolaminates have an overabundance of oxygen, while amorphous ones lack oxygen. The superabundance of oxygen on the crystalline film surface was illustrated by a schematic representation that described this phenomenon observed for PEALD TiO2/Al2O3 nanolaminates. The transition from crystalline to amorphous phase increased the surface hardness and the optical gap and decreased the refractive index. Therefore, the doping effect of TiO2 by the insertion of Al2O3 monolayers showed that it is possible to adjust different parameters of the thin-film material and to control, for example, the mobility of the hole-electron pair in the metal-insulator-devices semiconductors, corrosion protection, and optical properties, which are crucial for application in a wide range of technological areas, such as those used to manufacture fluorescence biosensors, photodetectors, and solar cells, among other devices.