Bolometric properties of oxygen atmosphere annealed Nb:TiO2−x films for infrared detectors

The aim of this paper is to investigate the effects of oxygen atmosphere annealing on the bolometric properties of Nb: TiO2−x samples for infrared detectors. We conducted the structural and composition analyses of as-deposited and annealed samples. The structural properties demonstrate an improvement in the film crystallinity and the composition analysis confirms the compensation of oxygen vacancies though post-deposition annealing in an oxygen atmosphere. A test device was fabricated to find the bolometric properties of the resistivity, temperature coefficient of resistance (TCR), 1/f noise parameter, bolometric parameter (β) and thermal stability. The logarithmic decrement of the resistivity with the temperature confirms that both the as-deposited and annealed test device samples show typical semiconducting behavior. Meanwhile, the annealed samples show lower TCR values while they have high resistivity due to their small changes in resistance with the temperature. The sample annealed for 20 min has good thermal stability and is similar in terms of the 1/f noise and β values to the as-deposited samples. The obtained results suggest that the post-deposition annealing of TNO samples in an oxygen atmosphere will lead to much stronger thermal stability compared to that of an as-deposited sample.