Graphene-Si Schottky diode in environmental conditions at low NH3 ppm level

In this work, we present the behavior of a graphene/silicon Schottky diode exposed to NH₃ flow of few tens of parts-per-million (ppm), at standard temperature and humidity conditions. Graphene was synthesized by Liquid Phase Exfoliation and transferred onto the Silicon substrate by drop casting. The Schottky barrier characterization towards NH₃ was performed at a reverse bias of -3V in the range 10 ppm-200 ppm. Results show the effect on the device electric current of ammonia concentrations as low as 10 ppm, with a good repeatability of the voltamperometric response. The variations ΔφNH₃, of the Schottky barrier, are reported as a function of the gas concentration. A spontaneous restoring is finally observed for the device.