Temperature dependent characteristics of graphene/silicon Schottky junction

摘要

Graphene/silicon Schottky junction has been reported as a promising device for chemical sensor, biological sensor and photodetector applications. However, abnormal characteristics are often reported and these ambiguities are explained inconsistently in the literature. This work aims at characterising the temperature effects on the current-voltage characteristics so as to explore the physical mechanisms leading to the abnormal behaviours of graphene/silicon Schottky junction. Particular attention is on the effect of silicon surface states which have been studied quite comprehensively in various silicon devices but have not been given enough attention for the graphene/Si structure. Results show that a graphene/Si Schottky junction could have quite different temperature dependences on the barrier height, ideality factor and reverse characteristics as compared with metal/semiconductor contacts. The dangling bonds on silicon surface, isolated by the ultrathin graphene layer, are still electrically active and play an important role in the carrier transport, photonic and chemical sensing capabilities of the graphene/Si junction. Graphene/Si contact prepared by transfer method cannot be a good Schottky junction from the electronic property and stability points of view.