Capacitive Humidity Sensors With High Sensitivity and Subsecond Response Times

Capacitive-based humidity sensors were fabricated using coplanar interdigitated electrodes coated with nanostructured TiO2thin films produced by glancing angle deposition. In this letter, we show that increased sensitivity (nF/%RH) is obtained by decreasing the electrode periodicity or by increasing the planar area of the electrodes, or both. The devices were sensitive over a wide range of relative humidity levels (92%) and exhibited extremely fast, subsecond response times. Typical adsorption and desorption response times were measured to be400 ms, respectively