Sharp switching behaviour in graphene nanoribbon p-n junction

The experimental study of interband quantum mechanical tunnelling in graphene nanoribbons is a major step to realizing graphene tunnelling-based field effect transistors (TFET). Here, we report the sharp switching behaviour observed in an electrostatically controlled graphene nanoribbon p-n junction in pn and np biasing. We demonstrate current modulation with a slope of 42 mV/dec over five order of magnitude in drain current at 5 K when the device is switched from nn to np configuration. This slope is unaffected by temperature up to 50 K. The suppression of carrier transmission in the OFF state is attributed to the finite bandgap of the ∼15 nm wide graphene nanoribbon channel. We show that the reported device characteristics can be explained by band-to-band tunnelling through the junction. This work is expected to offer valuable insight into BTBT in GNRs and be a valuable contribution towards competitive graphene TFETs.

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