Hydrogen-radical durability of TiO2 thin films for protecting transparent conducting oxide for Si thin film solar cells

Hydrogen-radical durability of TiO₂ thin films has been investigated under conditions for preparing Si thin film solar cells by catalytic chemical vapor deposition method. It is found that the composition and the optical transmittance of TiO₂ films are almost the same before and after hydrogen-radical exposures with a filament temperature at approximately 1700 °C and a H₂ pressure of approximately 133 Pa. The durability of TiO₂ film has also been observed even under the condition with higher hydrogen-radical density under a filament temperature at approximately 1900 °C, in which SnO₂ and ZnO are easily deoxidized. The application of TiO₂ film as a protecting material of transparent conducting oxide film for Si thin film solar cells are discussed by the hydrogen-radical durability and fundamental properties of TiO₂ thin film.