Effect of sputtering pressure on microstructure and bolometric properties of Nb: TiO2-x films for infrared image sensor applications

Abstract

This study aims to investigate the influence of the sputtering pressure (PS) on Nb:TiO2-x films to enhance the bolometric properties. A decrease in the growth rate with the sputtering pressure was perceived in amorphous Nb:TiO2-x films. The incorporation of oxygen with PS was confirmed in an X-ray photo electron spectroscopy analysis. The electrical resistivity was increased with an increase in PS due to a decrease in the number of oxygen vacancies. The linear I-V characteristics confirmed the ohmic contact behavior between the Nb:TiO2-x layer and the electrode material. The present investigation finds that the sample with lower resistivity has good bolometric properties with low noise and high universal bolometric parameters. Finally, the Nb:TiO2-x sample deposited at a sputtering pressure of 2 mTorr shows better bolometric properties than other materials for infrared image sensor applications.