▎ 摘　　要

A reverse bias tunable Pd- and Pt-functionalized graphene/Si heterostructure Schottky diode H-2 sensor has been demonstrated. Compared to the graphene chemiresistor sensor, the chemi-diode sensor offers more than one order of magnitude higher sensitivity as the molecular adsorption induced Schottky barrier height change causes the heterojunction current to vary exponentially in reverse bias. The reverse bias operation also enables low power consumption, as well as modulation of the atomically thin graphene's Fermi level, leading to tunable sensitivity and detection of H-2 down to the sub-ppm range.