Change in carrier type of sputtered Nb₂O₅ thin films by varying deposition temperature and annealing

Abstract

Nb2O5 thin films were grown by reactive RF-magnetron sputtering by varying the substrate temperature in the 50–400 °C range. After deposition, the films were also subjected to annealing (550 and 800 °C). The results show that with increasing deposition temperature, the Urbach energy and disorder decrease. Films grown at 50 and 300 ºC exhibited electrons as the majority carrier, with densities of 3.2 × 1014 cm⁻³ and 1.2 × 1017 cm⁻³, respectively, while films grown at 400 °C presented holes as the majority carrier and a density of 8.5 × 1014 cm⁻³. Films grown at 300 °C and annealed at 800ºC underwent a carrier type inversion and exhibited negative resistance behavior, associated with the formation of niobium defects and compensation of oxygen vacancies. The possibility of controlling the electrical and electronic nature of Nb2O5 films grown by RF-magnetron sputtering by varying deposition and annealing temperatures is demonstrated here.