Ultrahigh on/off-current ratio γ-graphyne-1 nanotube-based sub-10-nm TFET modeling and simulation

Abstract

The use of γ-graphyne-1 nanotubes (GyNTs) in tunneling field effect transistors (TFETs) suppresses ambipolarity and enhances the subthreshold swing (\(\mathrm{SS}\)) of TFETs, due to the large energy band gap and high electron effective mass of GyNTs. In this research, the analysis of the structural, electronic and thermoelectric properties of the γ-graphyne-1 family under the deformation potential (DP) approach reveals that the electron–phonon mean free path (MFP) of an armchair GyNT (3AGyNT) and zigzag GyNT (2ZGyNT) are \(24\) and \(279\) nm, respectively. Therefore, ballistic transport of sub-10-nm 3AGyNT-TFETs and 2ZGyNT-TFETs in different channel lengths is investigated utilizing the non-equilibrium Green’s function (NEGF) formalism in the DFTB platform. An ultrahigh \(\mathrm{on}/\mathrm{off}\)-current ratio (\(\mathrm{OOCR}\)) value of 1.6 × 1010 at \(V_{DD} = 0\). \(2 \;{\text{V}}\) and very low point \({\text{SS}}\) of \(5 \;{\text{mV}}/{\text{dec}}\) were demonstrated by the 3AGyNT-TFET with a channel length of 9.6 nm. 2ZGyNT-TFETs show higher on-state current and \({\text{SS}}\) and lower \({\text{OOCR}}\) than those of 3AGyNT-TFETs. A linear relationship was found between channel length and logarithmic off-state current that is consistent with the WKB approximation. The obtained results along with the ultralow power consumption of the proposed GyNT-TFETs make them candidates to replace digital silicon MOSFETs in next-generation nanoelectronic devices.