Gas sensing properties of indium–gallium–zinc–oxide gas sensors in different light intensity

• The sensing properties of semiconductor gas sensors can be modulated by the light emitting diode (LED) power.
• Different LED intensities affected the gas sensor sensitivity, which decays with increasing LED intensity.
• At lower intensity, greater sensitivity and resistance change of the sensor were obtained.
• The response time are larger at lower intensity.

We have successfully observed the change in indium–gallium–zinc–oxide (IGZO) gas sensor sensitivity by controlling the light emitting diode (LED) power under the same gas concentrations. The light intensity dependence of sensor properties is discussed. Different LED intensities obviously affected the gas sensor sensitivity, which decays with increasing LED intensity. High LED intensity decreases not only gas sensor sensitivity but also the response time (T90), response time constant (τres) and the absorption rate per second. Low intensity irradiated to sensor causes high sensitivity, but it needs larger response time. Similar results were also observed in other kinds of materials such as TiO2. According to the results, the sensing properties of gas sensors can be modulated by controlling the light intensity.

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