Optimization of post-deposition annealing temperature for improved signal-to-noise ratio in In2O3 gas sensor.

This paper investigates the effects of post-deposition annealing (PDA) temperature on H₂S gas sensing and low-frequency noise characteristics of In₂O₃ gas sensors. In₂O₃ thin-films are deposited using the radio frequency (RF) sputtering method at an RF power of 150 W and post-annealed at various temperatures (200, 300, and 400 °C). The response of the In₂O₃ gas sensor to H₂S decreases with increasing PDA temperature due to the increase of grain size. However, the In₂O₃ post-annealed at 200 °C shows the largest 1/f noise since the damaged sensing material-substrate interface is not fully recovered by the PDA. The sensors post-annealed at a higher temperature (300 °C and 400 °C) recover the damaged interface. Thanks to its moderate response and noise level, the sensor post-annealed at 300 °C shows the largest signal-to-noise ratio. [ABSTRACT FROM AUTHOR]