Temperature-Driven Rectification Reversal Observed in Graphene/Semiconductor Junction

Abstract

We report the temperature-dependent reversal in the rectification direction of the graphene/n-Si(001) junction. The forward current is observed to be significantly suppressed at low temperature and becomes smaller than the reverse current. This reversal of rectification direction can be explained by the asymmetric carrier injection at the graphene/n-Si(001) interface and the suppression of electron-hole recombination which is one of the main contributors to the forward current. The modulation of graphene work function by the surface state charges and space charges can induce a considerable amount of holes for the forward bias, but not for the reverse bias. As temperature decreases, the recombination current is suppressed, and the asymmetricity of carrier injection at the graphene/n-Si(100) interface becomes more and more significant in accordance with the carrier scattering being reduced. Thus, the forward current driven by the thermionic emission becomes smaller than the reverse current and the intriguing inverse rectifying behavior is unveiled. Our findings offer the intuition for asymmetric carrier injection at the inter-dimensional Schottky junction and a new class of device structure realizing temperature-dependent rectification switching.