Graphene-based Schottky device detecting NH3 at ppm level in environmental conditions

We present a graphene/n-Si Schottky junction for NH3 detection at level of few tens of parts-per-million (ppm). Graphene was synthesized by Liquid Phase Exfoliation and transferred onto the Si by drop casting. The Schottky barrier characterization towards NH3 was performed by volt-amperometric measurements in the range 10-200 ppm at bias of -3V. The characterization in the test chamber simulated environmental conditions by Relative Humidity at 50% and temperature at 295 K. Results suggest that the NH3 induces a barrier height modulation with current variations up to 4% for 200 ppm. In environmental conditions, a spontaneous restoring is observed for the device.