Negative terahertz dynamic conductivity in electrically induced lateral p–i–n junction in graphene

We analyze a graphene tunneling transit-time device based on a heterostructure with a lateral p–i–n junction electrically induced in the graphene layer and calculate its ac characteristics. Using the developed device model, it is shown that the ballistic transit of electrons and holes generated due to interband tunneling in the i-section results in the negative ac conductance in the terahertz frequency range. The device can serve as an active element of terahertz oscillators