The concept of a novel graphene P-I-N junction switching device with ananoribbon is proposed, and its basic operation is demonstrated in anexperiment. The concept aims to optimize the operation scheme for graphenetransistors toward a superior on-off property. The device has two bulk grapheneregions where the carrier type is electrostatically controlled by a top gate,and these two regions are separated by a nanoribbon which works as aninsulator. As a result, the device forms a (P or N)-I-(P or N) junctionstructure. The off state is obtained by lifting the band of the bulk grapheneof the source (drain) side and lowering that of the drain (source) side, sothat the device forms a P-I-N (N-I-P) junction. In this configuration, theleakage current can be reduced more effectively than the conventional singlegate transistors with the same band gap size due to a high barrier height and along tunneling length in the nanoribbon. The on state is obtained by flippingthe polarity of the bias of either top gate to form a P-I-P or N-I-N junction.An experiment showed that the drain current was suppressed in the cases ofP-I-N and N-I-P compared to the cases of P-I-P and N-I-N, and all of thebehaviors were consistent with what was expected from the device operationmodel.
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