Thermoelectric properties of armchair phosphorene nanoribbons in the presence of vacancy-induced impurity band

TL;DR

This study investigates how periodic vacancies in armchair phosphorene nanoribbons create impurity bands that enhance thermoelectric properties, suggesting their potential as efficient thermoelectric power generators.

Contribution

It introduces a theoretical model for impurity band formation in APNRs due to vacancies and explores their impact on thermoelectric performance.

Findings

Vacancy-induced impurity bands form inside the bandgap.

Nanopore size and spacing significantly affect thermoelectric efficiency.

APNRs can serve as highly effective thermoelectric power modules.

Abstract

Armchair phosphorene nanoribbons (APNRs) are known to be semiconductors with an indirect bandgap. Here, we propose to introduce new states in the gap of APNRs by creating a periodic structure of vacancies (antidots). Based on the tight-binding model, we show that a periodic array of vacancies or nanopores leads to the formation of an impurity band inside the gap region. We first present an analytical expression for the dispersion relation of an impurity band induced by hybridization of bound states associated with each single vacancy defect. Then, we increase the size of vacancy defects to include a bunch of atoms and theoretically investigate the effect of nanopores size and their spacing on electronic band structure, carrier transmission function, and thermoelectric properties. Our analysis of the power generation rate and thermoelectric efficiency of these structures reveals that an ANPR can be used as a superb thermoelectric power generation module.