Tunable graphene/Si chemi-diode H2 sensor: Comparison between Pd and Pt functionalization, and effect of illumination

Tunable graphene/Si heterostructure Schottky diode H₂ sensor with two different metal (Pd and Pt) functionalization has been demonstrated. In reverse bias, the molecular adsorption induced Schottky barrier height change causes the heterojunction current to vary exponentially which results in more than an order of higher sensitivity of the chemi-diode sensor compared to the graphene chemiresistor sensor. Tunable sensitivity of the sensor has been achieved through graphene Fermi level modulation by varying the reverse bias magnitude. Operation in reverse bias also enabled low power consumption.