Nb doping effect on TiO2−x films for bolometer applications

• Nb-doped TiO2−x films are deposited by RF magnetron reactive sputtering method.
• Nb doping on TiO2−x makes the variation of the resistivity by changing pO2 reduced.
• The ratio of Nb/(Nb+Ti) remains nearly constant (1.0%) at different pO2 levels.
• The improved bolometric properties in Nb-doped TiO2−x thin films were investigated.

Nb-doped TiO2−x thin films were deposited using a 1 at% niobium doped titanium target by RF reactive magnetron sputtering at various oxygen partial pressures (pO2). The films appeared amorphous in the pO2 range of 4.4–4.7% with resistivity ranging from 0.39 Ω cm to 2.48 Ω cm. Compared to pure TiO2−x films, the resistivity of the Nb-doped TiO2−x films did not change sensitively with the oxygen partial pressure, indicating that the resistivity of the films can be accurately controlled. 1/f noise parameter of Nb-doped TiO2−x films were found to decrease largely while the measured temperature coefficient of resistance (TCR) of the films was still high. The obtained results indicate that Nb-doped TiO2−x films have great potential as an alternative bolometric material.

Figure optionsDownload as PowerPoint slide