Graphene based Nano-Rectifiers

Most efforts on graphene electronic devices have been made on graphene transistors. This is a very challenging task and often requires generating a suitable bandgap in order to achieve a reasonable on/off ratio while preserving the carrier mobility. In contrast to transistors, the functionality of some types of diodes does not necessarily require a large bandgap. In particular, a nano-rectifier known as the ballistic rectifier benefits of long carrier mean-free path in graphene without being sensitive to bandgap. In this invited paper, we review our recent work on ballistic rectifier structures by creating an asymmetric cross-junction in a single-layer graphene flake. A mobility up to 200,000 cm 2 /Vs is achieved, ensuring a mean-free-path well beyond that required for the device to operate in the ballistic regime. This enables a very high intrinsic responsivity at room temperature. Taking advantage of the four-terminal device architecture in which the output channels are orthogonal to the input channels, we show that the device noise is hardly influenced by the input and is mainly limited by thermal noise, and this enables an exceptional noise-equivalent power in the order of pW/Hz 1/2 .