Study On Graphene Antidot Nanoribbon Tunnel Field-effect Transistor

Tunneling field effect transistors（TFETs）have the advantages of low subthreshold swing and high switching current ratio,and have good application prospects in the field of low power consumption.Graphene nanoribbons（GNRs）are one of the ideal materials for TFETs due to their tunable energy gap（E_g）and planar structure.Since the on-state current(I_on)density of the TFET is limited by the tunneling length,in order to reduce the tunneling length and achieve good switching performance of the device,constructing a heterojunction（HJ）is an extremely effective means.However,traditional HJs usually suffer from interface state problems caused by lattice mismatch,and the energy band structure is difficult to adjust.Therefore,the construction of HJs（hereinafter collectively referred to as HJs）has become one of the solutions.In this paper,a method for constructing HJ TFETs using GNRs is proposed,and its transport properties and mechanisms are deeply analyzed.The main work is as follows:In this paper,a scheme of forming a HJ between GNR and GANR is proposed.The effects of interface traps and Fermi level pinning caused by lattice mismatch or dangling bonds in traditional HJs are eliminated,and the tunneling blocking effect at the interface is effectively avoided.The effects of antidots size and density on the electrical properties of GANRs were systematically investigated,laying the foundation for exploring the HJ band combinations required for the excellent performance of TFETs.In this paper,density functional theory（DFT）and tight-binding model（TBM）are combined to calculate the energy band structure of GANRs;the non-equilibrium Green’s function method is used to simulate the transport properties of HJ devices;the deformation potential（DP）theory is used to explore the carrier mobility of the channel.The changes of the E_g and carrier mobility of GANRs with the antidots morphology were summarized,and a GNR/GANR HJ TFET model was constructed.While simulating the device transport characteristics and mechanisms,the effects of process issues on the tunneling performance were also explored.The simulation results show that the TFET designed in this paper can avoid the generation of interface states,exhibit continuously adjustable on-off state performance,and have certain process stability.