Scalability assessment of Group-IV mono-chalcogenide based tunnel FET

Abstract

Selection of appropriate channel material is the key to design high performance tunnel field effect transistor (TFET), which promises to outperform the conventional metal oxide semiconductor field effect transistor (MOSFET) in ultra-low energy switching applications. Recently discovered atomically thin GeSe, a group IV mono-chalcogenide, can be a potential candidate owing to its direct electronic band gap and low carrier effective mass. In this work we employ ballistic quantum transport model to assess the intrinsic performance limit of monolayer GeSe-TFET. We first study the electronic band structure by regular and hybrid density functional theory and develop two band k · p hamiltonian for the material. We find that the complex band wraps itself within the conduction band and valence band edges and thus signifies efficient band to band tunneling mechanism. We then use the k · p hamiltonian to calculate self-consistent solution of the transport equations within the non-equilibrium Green’s function formalism and the Poisson’s equation based electrostatic potential. Keeping the OFF-current fixed at 10 pA/μm we investigate different static and dynamic performance metrics (ON current, energy and delay) under three different constant-field scaling rules: 40, 30 and 20 nm/V. Our study shows that monolayer GeSe-TFET is scalable till 8 nm while preserving ON/OFF current ratio higher than 104.

Vortex‐Oriented Ferroelectric Domains in SnTe/PbTe Monolayer Lateral Heterostructures

“…[ 33 ] In SnTe, the directions parallel or antiparallel to its in‐plane polarization are defined as <10> (armchair), while the in‐plane direction perpendicular to its polarization is defined as <01> (zigzag). In contrast to previous theoretical studies, which focus on the interfaces along <10> directions [ 43–49 ] the SnTe/PbTe interfaces in our experiments mainly occur along the <11> directions (Figure 1b,c), which are also the preferred directions for the exposed edges in stand‐alone SnTe and PbTe ML nanoplates. [ 33 ] Atom resolved STM topography imaging confirmed atomically sharp interfaces (Figure 1d).…”

“…Because of the similar lattice parameters and compatible crystalline structures of MX MLs, it is straightforward to conceive functional LHSs between these materials and multiple theoretical studies have proposed devices such as diodes and tunneling FETs. [ 43–49 ] Nevertheless, because of the relatively strong interlayer coupling in orthorhombic MX materials, it is difficult to obtain large‐area MX ML flakes through mechanical exfoliation, making controlled growth or etching preparation methods a necessity. [ 50,51 ] Here we applied a two‐step MBE growth procedure to prepare SnTe/PbTe ML LHS nanoplates with PbTe in the core and SnTe at the perimeter, as schematically shown in Figure a.…”

Electron Density and Its Relation with Electronic and Optical Properties in 2D Mo/W Dichalcogenides

“…Ever since the discovery of isolated graphene through mechanical exfoliation [1], other graphene-like and two-dimensional (2D) materials, especially transition metal dichalcogenides (TMDs), have attracted significant research interest, in great part due to their unique structure-property relationships. The versatile applications of TMDs have been demonstrated in different fields, such as electronics, optoelectronics, energy storage and photocatalysis [2][3][4][5], despite ongoing challenges in device design and fabrication techniques [6]. Their typical honeycomb-like lattice structures consisting of single or few atomic layers are fundamental for their physical and chemical properties [7].…”

Electrically Doped Nanoscale Devices Using First-Principle Approach: A Comprehensive Survey

“…Using DFT and NEGF formalisms-based first-principle approach, nano-FET can be designed using various structural modifications. Various properties of these nano-FETs' are also observed, for example, scalability assessment, highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gaps, maximum obtainable current, RF performance, linearity investigation [54][55][56][57][58][59][60][61]. Conjugated co-oligomers-based molecular diode can be designed using DFT-and NEGFbased formalisms.…”