1 Development of humidity sensors based on nanostructured carbon films S. Miglio * , M. Bruzzi, M. Scaringella, D. Menichelli, E. Leandri, A. Baldi INFM-Dipartimento di Energetica, Via S. Marta 3, 50139 Firenze, Italy G. Bongiorno, P. Piseri and P. Milani INFM-Dipartimento di Fisica , Via Celoria 16, 20133 Milano, Italy Abstract Humidity sensors based on clusters assembled nanostructured carbon films in capacitive configuration have been manufactured and characterized. An electronic read-out system has been designed and implemented in order to measure the complex impedance of the device under operation. Devices under test show a fast dynamic response and a good sensitivity compared to capacitive commercial systems. A linear response is observed for relative humidity in the range 2-70%. Hysteresis is practically absent in this range, while for higher values it is at most of the order of 2%. Keywords: Nanostructured carbon; Supersonic Cluster Beam Deposition; capacitive humidity sensors * Corresponding author: Tel. +39 055 4796350; fax: +39 055 4796342. e-mail address miglio@fi.infn.it (S. Miglio).