Germanene nanoribbon tunneling field effect transistor (GeNR-TFET) with a 10 nm channel length: analog performance, doping and temperature effects

Abstract

In this paper, a scheme of the germanene nanoribbon tunneling field effect transistor (GeNR-TFET) is proposed. The characteristics and analog performance of the device were theoretically investigated by exploiting the electrical properties of a germanene nanoribbon and applying the doping concentration in the source and drain regions at 300 K and 4 K temperatures. The device parameters were obtained using a non-equilibrium Green's function (NEGF) method within the tight binding (TB) Hamiltonian. The TB Hamiltonian was extracted from the density functional theory (DFT) through the Wannier function. We find that by increasing the doping concentration the I on current increases which leads to an improvement of the I on /I off ratio to 10 5 . Moreover, decreasing the temperature from 300 K to 4 K causes the I off to becometen times smaller. We find that the device output characteristic displays a negative differential conductance with a good peak-to-valley ratio which is improved by increasing the doping concentration. The analog performance of the device is also investigated in the subthreshold regime of operation by varying the doping concentration. It is observed that by increasing the device doping concentration, the analog figures of merit can be improved.

First Principles Study of the Ambipolarity in a Germanene Nanoribbon Tunneling Field Effect Transistor

“…However, it can be seen that I ON is also reduced, so there is a trade-off between the ambipolar current and I ON . The sub-threshold swing (SS) is another important parameter of the field effect transistor that is calculated as SS=dV G /dlog(I) [11]. It is desired to have a low SS value, because it leads to better switching behavior of the transistor.…”

“…- [11] [43] In order to better illustrate important electronic properties of AGeNRs, we extracted the electron effective mass and the bandgap from Fig.8. Fig.…”

“…In recent years special attention has been paid to novel 2D materials and in particular to graphene, silicene and germanene because of their unique electronic, mechanical and optical properties. They offer a great potential for future nanoelectronic device applications [8][9][10][11].…”

“…They belong to group IV of the periodic table. Graphene is comprised of sp 2 hybridized carbon atoms and planar configuration whereas silicene and germanene because to the mixing of sp 2 and sp 3 hybridization have low-buckled structure [10][11][12][13][14][15][16][17][18]. Various studies show that graphene, germanene and silicene monolayers have zero bandgap.…”

“…Since in electronic devices, semiconductor materials with a tunable band gap is required it was necessary to overcome this issue. Utilizing these materials as nanoribbons with a desired width yields a nonzero bandgap which is tunable [8,11,12,[19][20][21]. Graphene, germanene and silicene nanoribbons are candidates for next generation devices due to significant electronic properties such as direct bandgap and light carrier effective mass [2,[22][23][24], high carrier mobility and high current density [23,[25][26][27].…”