Enhanced hydrogen gas sensitivity employing sputtered deposited NiO thin films


In this work, nickel oxide thin films have been successfully deposited on glass substrates by sputtering technique at different temperatures, and explored as a fast response sensor to hydrogen reducing gas.The nickel oxide sensor exhibits an increase of the conductance upon exposure to hydrogen gas of various concentrations at different operating temperatures. Pure sputtered NiO sample showed excellent sensitivity S of 1488%to hydrogen gas at the optimum H2: air concentration of 3.75%.The variation of the operating temperature of the film has led to a significant change in the sensitivity of the sensor with an ideal operating temperature of about 275℃ after which it began to saturate with increasing temperature and test was terminated. The variation of NiO sensor sample with H2: air gas ratio concentration showed linear relationship up to 3% after which saturation of S occurred.