On the feasibility of hearing electrons in a 1D device through emitted phonons

Amit Verma,Zahed Kauser,Reza Nekovei

doi:10.1038/s41598-021-85059-y

Amit Verma, Zahed Kauser + Show 1 more

Open Access

https://doi.org/10.1038/s41598-021-85059-y

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Abstract

This work investigates the vibrational power that may potentially be delivered by electron-emitted phonons at the terminals of a device with a 1D material as the active channel. Electrons in a 1D material traversing a device excite phase-limited acoustic and optical phonon modes as they undergo streaming motion. At ultra-low temperature (4 K in this study, for example), in the near absence of background phonon activity, the emitted traveling phonons may potentially be collected at the terminals before they decay. Detecting those phonons is akin to hearing electrons within the device. Results here show that traveling acoustic phonons can deliver up to a fraction of a nW of vibrational power at the terminals, which is within the sensitivity range of modern instruments. The total vibrational power from traveling optical and acoustic phonons is found to be in order of nW. In this work, Ensemble Monte Carlo (EMC) simulations are used to model the behavior of a gate-all-around (GAA) field-effect transistor (FET), with a single-wall semiconducting carbon nanotube (SWCNT) as the active channel, and a free-hanging SWCNT between two contacts. Electronic band structure of the SWCNT is calculated within the framework of a tight-binding (TB) model. The principal scattering mechanisms are due to electron–phonon interactions using 1st order perturbation theory. A continuum model is used to determine the longitudinal acoustic (LA) and optical (LO) phonons, and a single lowest radial breathing mode (RBM) phonon is considered.

Highlights

This work investigates the vibrational power that may potentially be delivered by electron-emitted phonons at the terminals of a device with a 1D material as the active channel
In order to quantify this, an Ensemble Monte Carlo (EMC) simulations-based device model is developed to model the electronic response of a (49,0) CNT as the active channel within two device configurations—a GAA field-effect transistor (FET), and as a free-hanging resistor—at an ultra-low temperature of 4 K
For the calculation of the electron scattering rates, the electron band structure is divided into 18,000 grid points covering the 1st and 2nd Brillouin Zone (BZ), while the phonon dispersion is divided into 10,000 grid points covering the 1st BZ

Summary

Introduction

This work investigates the vibrational power that may potentially be delivered by electron-emitted phonons at the terminals of a device with a 1D material as the active channel. In most practical applied voltage (or electric field) cases, electrons will be confined to relatively lower energy subbands, and relatively few phonon dispersion branches need be considered for inter and intra-subband scattering within those subbands.

Results

Conclusion