Modification of charge transport in nanostructured TiO2-x Schottky diodes via post fabrication annealing

An ordered, crack-free array of anatase TiO2 nanotubes were prepared via anodization and annealing at 550 degrees C. Oxygen vacancies are known to improve photocatalytic activity in TiO2 and were introduced using a facile low vacuum annealing. Stoichiometric and nonstoichiometric films were followed by a conformal Pt deposition at 250 degrees C using atomic layer deposition resulting in a current rectifying device, or Schottky diode. Here, we investigated the current-voltage effects of a post thermal treatment using 350 degrees C and 400 degrees C. This paper presents reproducible improvements in the charge transport behavior after a 350 degrees C post-fabrication annealing process. Oxygen vacancies resulted in the formation of a shunt resistance behavior of 10(5) omega and no overall performance improvements compared to stoichiometric films. Additionally, thermal treatments offered trap-based shifts from multiple trap distributions to a single trap distribution. This work hereby provides valuable experimental observations into understanding the effects of oxygen vacancies and effectively modifying the electronic properties of a conformal Pt/TiO2-x nanostructured junction using a facile post-thermal treatment.

Automated summary

An ordered, crack-free array of anatase TiO2 nanotubes were prepared via anodization and annealing, with oxygen vacancies introduced to improve photocatalytic activity. Post-fabrication annealing at 350°C was found to result in reproducible improvements in charge transport behavior.