Phonon limited anisotropic quantum transport in phosphorene field effect transistors

Abstract

Dissipative transport in 20 nm long phosphorene metal oxide semiconductor field effect transistor (MOSFET) is studied in armchair (AC) and zigzag (ZZ) directions. In a multiscale approach, the unit cell of phosphorene is first relaxed and bandstructure is calculated using hybrid density functional theory (DFT). The transport equations are then solved quantum mechanically under the nonequilibrium Green's function (NEGF) formalism using DFT-calibrated two band k•p hamiltonian. The treatment of electron phonon scattering is done under the self consistent Born approximation (SCBA) in conjunction with deformation potential theory. It is found that, optical phonon modes are largely responsible for degradation of ON-current apart from p channel AC MOSFET where acoustic phonon modes play a stronger role. It is further observed that electron-phonon scattering is more pronounced in ZZ direction whereas the diffusive ON-current of p-MOSFET in a given direction is higher than n-MOSFET. Further study on the complex bandstructure of phosphorene reveals band wrapping within bandgap region in AC direction and multiple crossings in ZZ direction. This signifies strong phonon assisted tunneling (PAT) in ZZ direction in comparison to AC direction. For completeness, drain current in AC tunnel field effect transistor (TFET) is calculated and electron-phonon scattering is observed only in the near vicinity of the OFF current.

Monte Carlo analysis of phosphorene nanotransistors

“…The on-current we obtain is at least one order of magnitude lower than the theoretical values previously published (Refs. [38][39][40]. As we have discussed in the Introduction section, the authors of Ref.…”

Computational perspective on recent advances in quantum electronics: from electron quantum optics to nanoelectronic devices and systems

“…Brahma et al studied electron-phonon coupling limited transport in phosphorene MOSFETs and TFETs [346]. Among others, the local density of states and spectral current densities were calculated (see figure 19) using hybrid DFT whereas transport is solved by an NEGF approach using a DFTcalibrated two-band k • p Hamiltonian.…”

“…Current spectrum (superimposed on the conduction edge profile) for the considered TFET in the dissipative regime in the OFF-state (left) and ON-state (right). Reprinted from[346], with the permission of AIP Publishing.…”

Effect of Electron – Phonon Interaction on the Magneto-optical Absorption in Monolayer Phosphorene

“…The term g qn denotes the square of the electron-phonon interacting matrix element. For the optical phonon scattering, within the deformation potential approximation, it is expressed as [19]: (9) where op…”