Ultraviolet-Light-Induced Desorption of Oxygen from SrTiO3 Surfaces

We have previously reported that SrTiO3-based thin films can be used to detect trace amounts of oxygen (e.g., down to 0.001 ppt). However, the SrTiO3 surfaces are highly active against oxygen adsorption. Therefore, the slow desorption response can affect the response speed of the sensors against the sudden change in oxygen concentration. We have reported that UV light irradiation is effective for accelerating oxygen desorption, and in this paper, we will show that the increase in the irradiation intensity of UV light can be an efficient way of improving the response speed. As an example, an apparent hysteresis in the sensor resistance versus oxygen concentration curve, which is shown after the UV irradiation at a low intensity, diminishes after the UV irradiation at a high intensity, even after short-lasting treatments. (C) 2011 The Japan Society of Applied Physics