Enhanced bolometric properties of TiO2−x thin films by thermal annealing

Abstract

The effect of thermal annealing on the bolometric properties of TiO2−x films was investigated. The test-patterned TiO2−x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2−x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I−V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2−x and the Ti electrode. Moreover, the annealed TiO2−x sample had a significantly low 1/f noise parameter (1.21 × 10−13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2−x film for a high-performance bolometric device.

Atomic layer deposition synthesized TiOx thin films and their application as microbolometer active materials

“…Consequently, the resistivity and temperature coefficient of resistance of titanium oxide films can be changed by many orders of magnitude by varying the deposition and annealing parameters. [13][14][15] There are numerous methods including sol-gel process, chemical vapor deposition, thermal evaporation, and reactive magnetron sputtering that can be used to prepare titanium oxide films. However, there are quite few TCR characterization of TiO x films which are mostly deposited by RF reactive magnetron sputtering as well as DC sputtering.…”

“…Kwon et al 16 investigated reactively sputtered TiO x films and obtained TCR value up to 2.8%/K. Reddy et al, 14,17 with the same deposition technique but different oxygen content, obtained the TCR value up to 3.66%/K. TiO x films prepared by Jiang et al 13 via reactive DC sputtering showed a TCR value of 3.3%/K.…”

Carbon Nanotube-Based Uncooled Bolometers: Advances and Progress

“…Most importantly, these schemes led to low bolometric noise in these Ti oxide systems. 110,111 Among all the semiconducting materials, vanadium oxide (VO x ) emerged to be the most promising candidate for IR BM, because of its high RT-TCR (in the range from ∼2%/K to ∼5%/ K), low 1/f noise, high IR absorption, and tunable resistivity. Pulsed DC sputtering and pulsed laser deposition techniques are widely used for the deposition of VO x thin films.…”

“…For instance, doping Nb led to an increase in the TCR value with a simultaneous reduction in the electrical resistivity. Most importantly, these schemes led to low bolometric noise in these Ti oxide systems. , …”

Improvement of the thermal stability of Nb:TiO2−xsamples for uncooled infrared detectors

“…For that reason, we focused on TiO 2−x as an alternative heat-sensitive material, as great progress has been made in the areas of device fabrication and improvements of bolometric properties [12][13][14]. Conversely, TiO 2−x materials are highly sensitive to oxygen, and it is very difficult to tune the resistivity value during the fabrication process of the samples.…”