Aerosol-assisted chemical vapour deposition of titanium dioxide thin films on silicon and implementation of a heterojunction diode

This study reports the development of titanium dioxide thin film with aerosol-assisted chemical vapour deposition and demonstrates the formation of a heterojunction diode with p-type silicon. The structural analysis of the thin film shows a nanostructured layer, with an average particle size of 32 nm, a layer thickness of 12 nm and the root mean square surface roughness value varying from 1.11 to 1.45 nm. The chemical analysis with XPS showed a non-stoichiometric and mixed state titanium dioxide thin film, with TiO1.9 being an appropriate representation of the film composition. The current–density voltage characteristics showed a high cut-in voltage of close to 2 V. A high cut-in voltage is due to the large value of valence band offset existing between titanium dioxide and silicon. However, the series resistance in the on-state is significantly high and can be attributed to the undoped nature of the titanium dioxide thin film.