Highly Sensitive Oxygen Sensing Characteristics Observed in IGZO Based Gasistor in a Mixed Gas Ambient at Room Temperature

Abstract

Oxygen (O₂) sensing in trace amounts and mixed gas is essential in many types of industries. Semiconductor sensors have proven to be invaluable tools for the O₂ measurements in a wide concentration range, but the sensors are only able to quantify O₂ in a concentration range of subppm, thus far, especially in mixed gas. We present in this paper a new concept for O₂ sensing with incomparable sensitivity using IGZO-films with oxygen vacancy-based conducting filaments (CFs). O₂ sensing relies on rupturing of the CFs, and the proposed device quickly recovers to the initial state using a pulse of 0.6 V/90 μs after the sensing. The proposed device has a high sensitivity of 14 even at an O₂ concentration of 500 ppb, a detection limit of 150 ppb for O₂ at RT, and excellent selectivity for O₂ in mixed gas, which is remarkable compared to other gas sensors. The proposed device can be widely used in gas sensors especially for detecting O₂ at a low ppb level, which is due to excellent sensing characteristics.