A new precursor route for the growth of NbO₂ thin films by chemical vapor deposition

Niobium dioxide (NbO2) exhibits metal-insulator transition (Mott transition) and shows the potential for application in memristors and neuromorphic devices. Presently growth of NbO2thin films requires high-temperature reduction of Nb2O5films using H2or sophisticated techniques such as molecular beam epitaxy and pulsed laser deposition. The present study demonstrates a simple chemical route of the direct growth of crystalline NbO2films by chemical vapor deposition using a freshly prepared Nb-hexadecylamine (Nb-HDA) complex. X-ray diffraction studies confirm the NbO2phase with a distorted rutile body-centered-tetragonal structure and the film grown with a highly preferred orientation onc-sapphire. X-ray photoelectron spectroscopy confirms the +4 oxidation state. The present method offers facile growth of NbO2films without post-reduction steps which will be assumed to be a cost-effective process for NbO2based devices.